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Low Grade Fibromyxoid Sarcoma (LGFMS), a rare entity characterized by bland histologic features, typically affects deep soft tissues of the trunk and lower extremities. Rare cases have been reported arising from the viscera and few demonstrating morphology of high-grade dedifferentiation. Here we report a 39-year-old Chinese woman presenting with primary lung LGFMS, which metastasized to the pancreas five years after diagnosis and then relapsed ten years later as a mediastinum mass. Microscopically, the lung and pancreatic lumps shared similar classical features of LGFMS, composed of bland spindle-shaped cells with low mitotic activity. However, the mediastinal mass had dedifferentiated morphology of dense sheets of round and epithelioid cells with high degree of nuclear pleomorphism and brisk mitosis. Molecular studies showed both classical and dedifferentiated areas had FUS::CREB3L2 rearrangement. However, the mediastinal dedifferentiated area presented with extra H193Y mutation of the TP53. Moreover, the mediastinal tumor displayed a strong and diffuse pattern of p53 expression immunohistochemically, but the primary lung and secondary pancreatic masses did not. Thus, we diagnosed the mediastinal mass as dedifferentiated LGFMS and proposed that TP53 mutation was probably the driver gene alteration in the process, which, to the best of our knowledge, has not been reported in the existing literature. [ABSTRACT FROM AUTHOR]

Dedifferentiated chondrosarcoma (DDCS) is a high-grade subtype of chondrosarcoma with the bimorphic histological appearance of a conventional chondrosarcoma component with abrupt transition to a high-grade, non-cartilaginous sarcoma. DDCS can be radiographically divided into central and peripheral types. Wide resection is currently the main therapeutic option for localized DDCS. Moreover, the effectiveness of adjuvant chemotherapy remains controversial. Therefore, we performed a systematic review of available evidence to evaluate the effect of adjuvant chemotherapy on localized DDCS. The purpose was to compare the 5-year survival rate among patients treated with surgery plus adjuvant chemotherapy or surgery alone for localized DDCS. The search was conducted in PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Of the 217 studies shortlisted, 11 retrospective non-randomized studies (comprising 556 patients with localized DDCS) were selected. The 5-year survival rates were similar between the two treatment groups (28.2% (51/181) vs. 24.0% (90/375), respectively). The overall pooled odds ratio was 1.25 (95% confidence interval: 0.80–1.94; p = 0.324), and heterogeneity I2 was 2%. However, when limited to peripheral DDCS, adjuvant chemotherapy was associated with prolonged survival (p = 0.03). Due to the paucity of included studies and the absence of prospective comparative studies, no conclusions can be drawn regarding the effectiveness or ineffectiveness of adjuvant chemotherapy for localized DDCS.

Dedifferentiation is a very rare phenomenon in uterine leiomyosarcoma (LMS). The aim of this study was to comprehensively analyze the clinicopathological characteristics of uterine dedifferentiated LMS (DDLMS). We reviewed electronic medical records and pathology slides from five patients with uterine DDLMS and performed immunostaining. The mean age of the patients was 56 years. Two patients presented with abdominal discomfort, while in three cases the uterine tumors were detected on routine medical examination. The mean size of the tumors was 17.0 cm. Four patients underwent hysterectomy. The initial stages were distributed as IB (2/5), IIIC (2/5), and IVC (1/5). Post-operative concurrent chemoradiation therapy, radiation therapy, and chemotherapy were administered in one, one, and two patients, respectively. Despite post-operative treatment, three patients developed metastatic recurrences in the abdominal and pelvic organs. Recurrence-free survival time ranged between 4 and 30 months. Histologically, the differentiated areas demonstrated the classic morphology of malignant smooth muscle differentiation, whereas the dedifferentiated areas resembled undifferentiated pleomorphic sarcoma and were characterized by large pleomorphic tumor cells admixed with haphazardly arranged atypical cells with marked nuclear pleomorphism. All cases also exhibited heterologous components, including chondrosarcoma (CSA; 3/5) and rhabdomyosarcoma (2/5). In two cases, the heterologous components were initially detected in primary tumors. In three cases, the primary tumors did not exhibit any dedifferentiated or heterologous components. Instead, more than half of the recurrent tumors consisted of heterologous components. Three cases showed a sharp demarcation between the LMS and CSA components, while in two cases the dedifferentiated area imperceptibly merged with the differentiated component. Immunostaining revealed that the dedifferentiated components exhibited a lack of desmin immunoreactivity in three of the four examined cases. A subset of uterine LMS represents various amounts and types of dedifferentiation and heterologous components in both primary and recurrent tumors. Routine recognition of DDLMS and distinction from its mimickers are required for accurate diagnosis and further characterization of these rare tumors. [ABSTRACT FROM AUTHOR]

Dedifferentiated chondrosarcoma (DDCS) is a high-grade subtype of chondrosarcoma with the bimorphic histological appearance of a conventional chondrosarcoma component with abrupt transition to a high-grade, non-cartilaginous sarcoma. DDCS can be radiographically divided into central and peripheral types. Wide resection is currently the main therapeutic option for localized DDCS. Moreover, the effectiveness of adjuvant chemotherapy remains controversial. Therefore, we performed a systematic review of available evidence to evaluate the effect of adjuvant chemotherapy on localized DDCS. The purpose was to compare the 5-year survival rate among patients treated with surgery plus adjuvant chemotherapy or surgery alone for localized DDCS. The search was conducted in PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Of the 217 studies shortlisted, 11 retrospective non-randomized studies (comprising 556 patients with localized DDCS) were selected. The 5-year survival rates were similar between the two treatment groups (28.2% (51/181) vs. 24.0% (90/375), respectively). The overall pooled odds ratio was 1.25 (95% confidence interval: 0.80–1.94; p = 0.324), and heterogeneity I2 was 2%. However, when limited to peripheral DDCS, adjuvant chemotherapy was associated with prolonged survival (p = 0.03). Due to the paucity of included studies and the absence of prospective comparative studies, no conclusions can be drawn regarding the effectiveness or ineffectiveness of adjuvant chemotherapy for localized DDCS. [ABSTRACT FROM AUTHOR]

Perineural invasion (PNI) has emerged as a key pathological feature and be considered as a poor prognostic factor in cervical cancer. However, the underlying molecular mechanisms are largely unknown. Here, PNI status of 269 cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) samples were quantified by using whole‐slide diagnostic images obtained from The Cancer Genome Atlas. Integrated analyses revealed that PNI was an indicative marker of poorer disease‐free survival for CESC patients. Among the differentially expressed genes, ADCYAP1 were identified. Clinical specimens supported that high expression of PACAP (encoded by ADCYAP1) contributed to PNI in CESC. Mechanistically, PACAP, secreted from cervical cancer cells, reversed myelin differentiation of Schwann cells (SCs). Then, dedifferentiated SCs promoted PNI by producing chemokine FGF17 and by degrading extracellular matrix through secretion of Cathepsin S and MMP‐12. In conclusion, this study identified PACAP was associated with PNI in cervical cancer and suggested that tumour‐derived PACAP reversed myelin differentiation of SCs to aid PNI. [ABSTRACT FROM AUTHOR]

Marina Pacheco,1,2 Rodolfo Guzmán,3 Patricia Bonilla4 1Department of Pathology, Complejo Hospitalario Metropolitano CSS, Social Security Fund, Panama, Panama; 2Sistema Nacional de Investigación; Secretaria Nacional de Ciencia, Tecnologia e Innovación, Panama, Panama; 3Department of Pathology, Hospital San Juan de Dios CCSS, San Jose, Costa Rica; 4Department of Orthopedics, Hospital del Niño Dr. José Renán Esquivel, Panama, PanamaCorrespondence: Marina Pacheco, Departamento de Patología, Complejo Hospitalario Metropolitano Dr. Arnulfo Arias Madrid CSS, Avenida José de Fábrega y Simón Bolivar, Bella Vista, Panama, Panama, Tel +507 503 6219, Email mpacheco@css.gob.paAbstract: The treatment of low-grade osteosarcomas is surgical resection with wide margins. In instances of dedifferentiation, a therapeutic paradigm similar to that of conventional high-grade osteosarcoma has not been adequately evaluated in these neoplasms. The main objective of this review was to define whether the addition of chemotherapy to surgical treatment has an impact on the survival of patients with dedifferentiated low-grade osteosarcomas. Secondary objectives were to observe the degree of histological response to neoadjuvant chemotherapy and to describe the percentage of de novo dedifferentiation. A systematic search of articles including dedifferentiated low-grade osteosarcomas, published between 1980 and 2022 was carried out in the PubMed, Cochrane and Scielo databases. A qualitative synthesis of the results was performed. Twenty-three articles comprising 117 patients were included. The survival of patients treated with surgery alone and surgery with chemotherapy was not statistically significant between the two groups. A good histological response was seen in 20% of specimens treated with neoadjuvant chemotherapy. De novo dedifferentiation was seen in approximately a fifth of low-grade osteosarcomas. The evidence available suggests that the addition of chemotherapy does not have an impact on the survival of patients with low-grade dedifferentiated osteosarcomas.Keywords: dedifferentiated, osteosarcoma, parosteal osteosarcoma, low-grade central osteosarcoma

Liposarcomas are malignant mesenchymal neoplasms that, although derived from adipocytes, may dedifferentiate to other cell types. We present an exceedingly rare case of epithelioid/neuroendocrine dedifferentiation with somatostatin expression of a pararenal retroperitoneal liposarcoma.

Liposarcoma is a malignant soft tissue tumor that rarely involves the gastrointestinal tract. The dedifferentiated type typically carries the worst prognosis. Here, we describe a rare case of dedifferentiated liposarcoma of the rectum in a young male patient who was treated with surgical excision. Treatment is often difficult and there is no clear consensus on the benefits of radiotherapy or chemotherapy.

Introduction: Lenvatinib is one of the approved treatments for radioiodine-refractory differentiated thyroid cancers. However, there is very limited data from India on real-world efficacy and adverse events of Lenvatinib and hence this analysis was performed. Methods: This was a retrospective analysis in which patients of radioiodine-refractory differentiated thyroid cancer as per the SELECT study criteria, who received lenvatinib, were selected for the study over the last 4 years. The baseline demographic characteristics, adverse events of lenvatinib, the date of progression and the date of overall survival (OS) were extracted from the electronic medical records of Tata Memorial Hospital. SPSS version 20 was used for analysis. Results: The median starting dose of lenvatinib was 20 mg. Fifteen events for progression had occurred and the median progression-free survival (PFS) was 12.2 months [95% CI: 4.4-not available (NA)]. The events for OS analysis were 12. The median OS was 35.3 months (95% CI: 11.4-NA). There was no impact on starting dose on PFS or OS. Conclusion: The real-world data of Lenvatinib suggest a lot of variability in the starting dose. In spite of this variability, the response rates and OS are similar to that noted in pivotal study. This suggests a case for need for more studies evaluating lower doses of Lenvatinib. [ABSTRACT FROM AUTHOR]

Dedifferentiated liposarcoma of the deep soft tissue of the lower extremities is an infrequent finding. Myxoid liposarcoma is considered the most common soft tissue neoplasia arising in this anatomic region. Divergent differentiation usually occurs within well-differentiated liposarcoma and is exceedingly rare in a myxoid liposarcoma. We report a 32-year-old man who developed a dedifferentiated liposarcoma of the thigh on the background of a pre-existing myxoid liposarcoma. The gross examination of the surgical specimen showed a 11/7/2 cm tumour mass with solid tan-grey areas and focal myxoid degeneration. The microscopic examination revealed a malignant lipogenic proliferation, containing round cells with hyperchromatic nuclei and atypical lipoblasts, confined to the basophilic stroma with a myxoid aspect. Abrupt transition towards a hypercellular, non-lipogenic area consisting of highly pleomorphic spindle cells with atypical mitotic figures was also noted. Immunohistochemical staining was performed. Tumour cells in the lipogenic area were intensely positive for S100 and p16, and CD34 staining highlighted an arborizing capillary network. The dedifferentiated tumour areas showed positive MDM2 and CDK4 staining within neoplastic cells, with the Ki 67 proliferation marker expressed in approximately 10% of the cells. Wild-type TP53 protein expression pattern was documented. Thus, the diagnosis of a dedifferentiated liposarcoma was established. This paper aims to provide further knowledge about liposarcomas with divergent differentiation at peculiar locations, emphasizing the importance of histopathologic examination and immunohistochemical analysis for establishing the diagnosis and assessing the therapeutic response and prognosis of this condition. [ABSTRACT FROM AUTHOR]

Dedifferentiation is a very rare phenomenon in uterine leiomyosarcoma (LMS). The aim of this study was to comprehensively analyze the clinicopathological characteristics of uterine dedifferentiated LMS (DDLMS). We reviewed electronic medical records and pathology slides from five patients with uterine DDLMS and performed immunostaining. The mean age of the patients was 56 years. Two patients presented with abdominal discomfort, while in three cases the uterine tumors were detected on routine medical examination. The mean size of the tumors was 17.0 cm. Four patients underwent hysterectomy. The initial stages were distributed as IB (2/5), IIIC (2/5), and IVC (1/5). Post-operative concurrent chemoradiation therapy, radiation therapy, and chemotherapy were administered in one, one, and two patients, respectively. Despite post-operative treatment, three patients developed metastatic recurrences in the abdominal and pelvic organs. Recurrence-free survival time ranged between 4 and 30 months. Histologically, the differentiated areas demonstrated the classic morphology of malignant smooth muscle differentiation, whereas the dedifferentiated areas resembled undifferentiated pleomorphic sarcoma and were characterized by large pleomorphic tumor cells admixed with haphazardly arranged atypical cells with marked nuclear pleomorphism. All cases also exhibited heterologous components, including chondrosarcoma (CSA; 3/5) and rhabdomyosarcoma (2/5). In two cases, the heterologous components were initially detected in primary tumors. In three cases, the primary tumors did not exhibit any dedifferentiated or heterologous components. Instead, more than half of the recurrent tumors consisted of heterologous components. Three cases showed a sharp demarcation between the LMS and CSA components, while in two cases the dedifferentiated area imperceptibly merged with the differentiated component. Immunostaining revealed that the dedifferentiated components exhibited a lack of desmin immunoreactivity in three of the four examined cases. A subset of uterine LMS represents various amounts and types of dedifferentiation and heterologous components in both primary and recurrent tumors. Routine recognition of DDLMS and distinction from its mimickers are required for accurate diagnosis and further characterization of these rare tumors.

Malignant melanoma (MM) is traditionally known as the "great mime" of human pathology, as it is potentially capable of imitating the most disparate neoplasms. It is known that in addition to the more classic histotypes of MM, there are also rare forms, including angiomatoid MM. Similarly, it has been amply demonstrated in the literature that MM is capable of dedifferentiating, losing melanocytic lineage markers, constituting a diagnostic challenge for the pathologist. Although 5 cases of primary angiomatoid MM have been described in the literature, to the best of our knowledge, no cases of dedifferentiated melanoma with pseudo-angiomatoid aspects have ever been described. In this paper, we present a very rare case of partially dedifferentiated MM in which the most dedifferentiated component lost melanocytic lineage immunohistochemical markers and assumed a pseudo-angiomatous morphology. Given the rarity of the case, we carried out a literature review of similar cases described, trying to draw new future perspectives not only about this particular variant of MM but also about the widest field of dedifferentiation/undifferentiation of MM. [ABSTRACT FROM AUTHOR]

This review provides an overview of histopathology, clinical presentation, molecular pathways, and potential new systemic treatments of high-grade chondrosarcomas (CS), including grade 2–3 conventional, dedifferentiated, and mesenchymal CS. The diagnosis of CS combines radiological and histological data in conjunction with patient clinical presentations. Conventional CS is the most frequent subtype of CS (85%) and represents about 25% of primary bone tumors in adults; they can be categorized according to their bone location into central, peripheral, and periosteal chondrosarcomas. Central and peripheral CS differ at the molecular level with either IDH1/2 mutations or EXT1/2 mutations, respectively. CDKN2A/B deletions are also frequent in conventional CS, as well as COL2A1 mutations. Dedifferentiated CS develops when low-grade conventional CS transforms into a high-grade sarcoma and most frequently exhibits features of osteosarcoma, fibrosarcoma, or undifferentiated pleomorphic sarcoma. Their molecular characteristics are similar to conventional CS. Mesenchymal CS is a totally different pathological entity exhibiting recurrent translocations. Their clinical presentation and management are different too. The standard treatment of CSs is wide en-bloc resection. CS are relatively radiotherapy resistant; therefore, doses >60 Gy are needed in an attempt to achieve local control in unresectable tumors. Chemotherapy is possibly effective in mesenchymal chondrosarcoma and is of uncertain value in dedifferentiated chondrosarcoma. Due to resistance to standard anticancer agents, the prognosis is poor in patients with metastatic or unresectable chondrosarcomas. Recently, the refined characterization of the molecular profile, as well as the development of new treatments, allow new therapeutic options for these rare tumors. The efficiency of IDH1 inhibitors in other malignancies suggests that these inhibitors will be part of IDH1/2 mutated conventional CS management soon. Other treatment approaches, such as PIK3-AKT-mTOR inhibitors, cell cycle inhibitors, and epigenetic or immune modulators based on improving our understanding of CS molecular biology, are emerging. [ABSTRACT FROM AUTHOR]

Simple Summary: When compared microscopically to normal cells, cancer cells are graded on a continuum from well differentiated to undifferentiated, meaning that well differentiated cancer cells look similar to normal cells and undifferentiated ones look very different. Patient survival outcomes typically decrease along this continuum. However, some cancer cells are so undifferentiated that it is not certain from which cell type they arose from. It is not known if these patients have worse outcomes compared to undifferentiated cancers where the cell type origin can be determined. In this study, we show that patient outcomes from undifferentiated cancers depend on the site, and generally, outcomes are worse compared to undifferentiated cancers with a discernible cell type, but there are some notable exceptions. This work illustrates that tumor site has significant impacts on patient survival even when accounting for multiple demographic, clinical, and histological factors. Undifferentiated carcinomas are rare cancers that lack differentiation, such that they cannot be classified into any conventional histological subtype. These cancers are uniquely codified and are contrasted to carcinomas with an ascertained histology that are grade classified as poorly differentiated, undifferentiated, or anaplastic. Given their rarity, there are no standardized overviews of undifferentiated carcinomas in the literature, and it is unknown if their classification indicates a unique prognosis profile. In this study, we summarize the clinicodemographic and mortality outcomes of undifferentiated carcinomas in twelve primary sites and for unknown primaries, comprising 92.8% of all undifferentiated carcinomas diagnosed from 1975–2017 in the Surveillance, Epidemiology, and End Results Program (SEER). Incidence has decreased to 4 per 1 million cancer diagnoses since 1980. Relative to the most common undifferentiated cancers with a defined histology, undifferentiated carcinomas have overall worse prognosis, except in nasopharyngeal and salivary gland cancers (hazard ratio (HR) 0.7–1.3). After correction for age, sex, race, detection stage, and treatment (surgery, chemotherapy, and radiotherapy), the mortality HR averages 1.3–1.4 for these cancers relative to histologically ascertainable undifferentiated cancers. However, there is a wide variance depending on site, signifying that survival outcomes for undifferentiated carcinomas depend on factors related to site tumor biology. [ABSTRACT FROM AUTHOR]

Paratesticular liposarcoma is a sporadic urological tumor. We report the clinical presentation, treatment course, and prognosis of 2 cases of primary paratesticular liposarcoma with different pathological types, with the aim of further understanding the diagnosis and treatment of this rare disease. Case 1 was a 53-years-old male patient who presented with left scrotal enlargement with swelling 3 years ago and was considered to have a testicular malignancy on preoperative CT scan and enhanced MRI. The patient underwent resection of the left scrotal mass and left orchiectomy under general anaesthesia. Histopathological study confirmed the diagnosis of dedifferentiated liposarcoma. At the 4-months follow-up, no local recurrence or distant metastasis was observed. Case 2 is a 42-years-old male patient with a left scrotal mass which was discovered six months ago. Preoperatively, he underwent CT plain and enhanced MRI examinations suggesting an intrascrotal occupancy. The patient underwent scrotoscopic excision of the left scrotal mass under general anesthesia. Histopathological studies confirmed the diagnosis of highly differentiated liposarcoma. At the 10-months follow-up, no local recurrence or distant metastasis was observed. Preoperative differential diagnosis of paratesticular liposarcoma should be noted with testicular tumor and extra-abdominal hernia. Extensive local excision and, if necessary, concomitant radical testicular resection is the treatment of choice. If the tumor in the scrotum spreads to the inguinal region, surgical removal with the aid of a scrotoscope may be attempted. This procedure avoids the formation of a large incision in the inguinal region compared to traditional open surgery. Patients commonly experience local recurrence and less distant metastases after surgery, so long-term follow-up is recommended. [ABSTRACT FROM AUTHOR]

Dedifferentiated chondrosarcomas (DDCS) are highly aggressive tumors with poor outcomes. Chondrosarcoma (CS) can be categorized based on localization (periosteal, central, and peripheral) or histology, with conventional CS being the most common subtype. However, rarer histological types, such as clear-cell CS, DDCS, and mesenchymal CS, also exist. We present a unique case of DDCS in a 28-year-old male who presented with swelling on the proximal phalanx of the fourth finger. Radiographs showed sclerotic margins and a central diaphyseal lytic lesion. Immunohistochemical analysis using S-100 and Ki67 markers confirmed the diagnosis of DDCS. Treatment involved a multidisciplinary approach, including surgical resection, adjuvant chemotherapy, and radiation therapy. This case underscores the importance of early identification of DDCS and the need for tailored management strategies to address its specific characteristics., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, A et al.)

BackgroundRetroperitoneal liposarcoma (RPLS) is a variety of soft tissue sarcoma that originates from mesenchymal cells. A tumor measuring greater than 30 cm is called a “giant liposarcoma.” A part of the neoplasm tends to grow in size, recur locally, or metastasize distantly. In those with such a condition, long-term survival is uncommon. Therefore, it is necessary to present a uniform and optimized program to improve the prognosis.MethodsBy successfully treating a multiple-recurrent giant retroperitoneal dedifferentiated liposarcoma (RP DDLPS) in July 2010, we hope to devise more comprehensive strategies to improve diagnosis, therapy, and outcome.ResultsIn July 2010, we thoroughly resected a giant multifocal RPLS with a concomitant part of the gastric wall. The histopathological examination revealed a high-grade (grade III) dedifferentiated liposarcoma. The patient was discharged uneventfully on the 15th postoperative day. She relapsed after 16 months and needed another complete excision. After 9 months, she died after the fourth recidive. The patient had experienced four recurrences and underwent operations with 15 years of follow-up.ConclusionsThe above demonstrates that we were able to successfully treat the multirecurrent giant RPLS, despite the patient’s poor medical condition, with meticulous management. Moreover, this indicates that long-term survival could be achieved for high-grade RP DDLPS.

Dedifferentiated Liposarcoma (DDLPS) is a rare subtype of liposarcoma with a high preponderance of local recurrence and distant metastasis. The frequent site of DDLPS is the retroperitoneum, followed by the limbs and trunk. The primary omental DDLPS is very rare and only a few cases have been reported in the literature. Here we report a rare case of primary giant DDLPS of omentum with intraperitoneal metastasis in a 61year old woman. The present case report adds to our knowledge, that a case of intraperitoneal DDLPS can mimic ovarian cancer clinically and should be considered in the differential diagnosis of a pelvic mass in postmenopausal women. [ABSTRACT FROM AUTHOR]

Study designRetrospective analysis.ObjectiveTo determine the epidemiology and prognostic indicators in patients with chondrosarcoma of the osseous spine.Summary of background dataChondrosarcoma of the spine is rare, with limited data on its epidemiology, clinicopathologic features, and treatment outcomes. Therapy centers on complete en bloc resection with radiotherapy reserved for subtotal resection or advanced disease.MethodsThe Surveillance, Epidemiology, and End Results Registry was queried for patients with chondrosarcoma of the osseous spine from 1973 to 2012. Study variables included age, sex, race, year of diagnosis, size, grade, extent of disease, and treatment modality.ResultsThe search identified 973 cases of spinal chondrosarcoma. Mean age at diagnosis was 51.6 years, and 627% of patients were males. Surgical resection and radiotherapy were performed in 75.2% and 21.3% of cases, respectively. Kaplan-Meier analysis demonstrated overall survival (OS) and disease-specific survival (DSS) of 53% and 64%, respectively, at 5 years. Multivariate Cox regression analysis showed that age (OS, P

Dedifferentiated liposarcoma of the deep soft tissue of the lower extremities is an infrequent finding. Myxoid liposarcoma is considered the most common soft tissue neoplasia arising in this anatomic region. Divergent differentiation usually occurs within well-differentiated liposarcoma and is exceedingly rare in a myxoid liposarcoma. We report a 32-year-old man who developed a dedifferentiated liposarcoma of the thigh on the background of a pre-existing myxoid liposarcoma. The gross examination of the surgical specimen showed a 11/7/2 cm tumour mass with solid tan-grey areas and focal myxoid degeneration. The microscopic examination revealed a malignant lipogenic proliferation, containing round cells with hyperchromatic nuclei and atypical lipoblasts, confined to the basophilic stroma with a myxoid aspect. Abrupt transition towards a hypercellular, non-lipogenic area consisting of highly pleomorphic spindle cells with atypical mitotic figures was also noted. Immunohistochemical staining was performed. Tumour cells in the lipogenic area were intensely positive for S100 and p16, and CD34 staining highlighted an arborizing capillary network. The dedifferentiated tumour areas showed positive MDM2 and CDK4 staining within neoplastic cells, with the Ki 67 proliferation marker expressed in approximately 10% of the cells. Wild-type TP53 protein expression pattern was documented. Thus, the diagnosis of a dedifferentiated liposarcoma was established. This paper aims to provide further knowledge about liposarcomas with divergent differentiation at peculiar locations, emphasizing the importance of histopathologic examination and immunohistochemical analysis for establishing the diagnosis and assessing the therapeutic response and prognosis of this condition.

Endometrial cancer (EC) is one of the most common gynecologic cancers worldwide. There were 417,367 newly diagnosed cases and 97,370 deaths due to this disease worldwide in 2020. The incidence rates have increased over time, especially in countries with rapid socioeconomic transitions, and EC has been the most prevalent gynecologic malignancy in Taiwan since 2012. The new EC molecular classifications of The Cancer Genome Atlas (TCGA) Research Network include clear-cell carcinoma, serous carcinoma, and carcinosarcoma, while undifferentiated/dedifferentiated EC (UDEC) is not mentioned, and most previous clinical trials for EC have not included UDEC. UDEC is rare, has an aggressive growth pattern, tends to be diagnosed at an advanced stage, and is resistant to conventional chemotherapy. In this review, case series or case reports on the clinical features and genomic/epigenetic and expression profiles on UDEC data are summarized in order to identify potential molecular targets for current and future research. [ABSTRACT FROM AUTHOR]

Surgical resection is the mainstay of treatment for retroperitoneal liposarcoma (RPLS). Herein, we describe a case of dedifferentiated RPLS successfully treated with an extended surgical approach with adjuvant chemotherapy. A 61-year-old male was referred to our hospital with a chief complaint of chest tightness. Abdominal computed tomography revealed a large retroperitoneal tumor, 11 cm in diameter, extensively invading the surrounding organs: the celiac axis, the splenic artery, the pancreatic body and tail, the lesser curvature of the stomach and the left adrenal gland. Endoscopic ultrasound-guided fine-needle aspiration biopsy confirmed dedifferentiated liposarcoma, suggesting aggressive tumor biology. We performed total gastrectomy combined with distal pancreatectomy with celiac axis and left adrenal gland resection with a curative intent. The postoperative course was almost uneventful. As the pathological findings indicated a positive margin with a well-differentiated liposarcoma component, we added adjuvant chemotherapy with four cycles of doxorubicin and ifosfamide (AI). Five years after primary surgery, regular follow-up CT demonstrated a pulmonary hilar lymph node enlargement and a tumor at paraesophageal locations. After downsizing chemotherapy with eribulin followed by pazopanib, he underwent partial esophagectomy with dissection of the paraesophageal tumor. The pathological findings indicated recurrence of dedifferentiated liposarcoma with a tumor-free surgical margin. He is currently alive without any evidence of recurrence almost 7 years after the first surgery and 15 months after the second surgery. The long-term survival gained in this patient indicates that extended resections and adjuvant chemotherapy could prolong survival in patients even with RPLS with dedifferentiated tumor histology. [ABSTRACT FROM AUTHOR]

Adipocytic tumours are among the most common mesenchymal neoplasms, and constitute a clinically, biologically and pathologically diverse group. Their wide histological spectrum and frequent morphological overlap have made classification and diagnosis challenging, with accurate classification being critical because of the considerable differences in prognosis and management between morphologically overlapping neoplasms. Ongoing advances in molecular genetics have aided significantly to our understanding of these neoplasms, with continuing evolution in classification. This review summarises the new developments in benign and malignant adipocytic neoplasms, with discussion of new entities and genetic findings, updates on the clinical and morphological spectrum, and the use of diagnostic immunohistochemistry and molecular markers in the differential diagnosis. [ABSTRACT FROM AUTHOR]

Retroperitoneal liposarcoma (RPLS) is a rare mesenchymal tumor which accounts for 0.02-0.7% of all malignancy. The presentations of these tumors are non-specific and early diagnosis is often missed. We are reporting a rare case of 17-year-old girl who came to us with complaints of abdominal distension and other non-specific symptoms but after few hours of admission, she had acute abdomen with hemodynamic instability. She underwent emergency laparotomy and found to have a giant 25 × 20 × 10 cm ruptured retroperitoneum tumor causing hemoperitoneum. The tumor involved left ovary and fallopian tube as well. Complete resection of tumor with left salpingooophorectomy was done. The patient was kept in intensive care unit and discharged in good health after 15 days. This presentation of RPLS has not been reported yet and may demand early diagnosis and management of these tumors. The histopathology revealed dedifferentiated liposarcoma with rhabdomyosarcomatous differentiation. The patient is completely fine at 16 months of follow-up while writing this report. Again, heterologous dedifferentiation of liposarcoma with spindle cell component is a rare morphologic spectrum. Liposarcomas can have various histologic types. In dedifferentiated types, the line of differentiation needs to be identified to decide further line of treatment. Therefore, thorough histopathological analysis and immunostaining is needed. Treatment includes complete surgical resection. Role of radiotherapy and chemotherapy is debatable and is still under trial. Dedifferentiated RPLS with rhabdomyosarcomatous differentiation is a rare tumor and its presentation as acute abdomen and hemoperitoneum has never been reported previously. [ABSTRACT FROM AUTHOR]

Abstract Background Retroperitoneal liposarcoma (RPLS) is the most commonly observed soft tissue sarcoma in the retroperitoneal space. Although the beneficial effect of chemotherapy for RPLS is controversial, there are some reports that have shown a considerable tumor-suppressive effect of chemotherapy in RPLS. We demonstrate a case of dedifferentiated RPLS, which was initially considered inoperable but was successfully treated by neoadjuvant chemotherapy and subsequent curative resection. Case presentation A 59-year-old female was referred to our hospital with a chief complaint of right lower quadrant abdominal pain. Abdominal computed tomography revealed a large retroperitoneal tumor with a maximum diameter of 11 cm. The tumor involved retroperitoneal major vasculatures, such as the right common iliac vein and artery, as well as the right psoas muscle and femoral nerve. The right ureter was also involved and obstructed by the tumor. A biopsy was performed through the retroperitoneal route, and the tumor was diagnosed as a dedifferentiated liposarcoma with the Fédération Nationale des Centres de Lutte Contre le Cancer grade 3. Because the tumor was highly invasive and complete resection was not feasible, we decided to administer neoadjuvant chemotherapy with doxorubicin and ifosfamide (AI). After completing 6 courses of AI, the tumor size was considerably reduced, and we decided to perform surgery with curative intent. Before laparotomy, femoro-femoral arterial bypass was performed to prepare for the right common iliac artery resection. Thereafter, the patient underwent laparotomy and tumor resection combined with right nephrectomy, resection of the right common iliac artery and vein, and resection of the right psoas muscle and femoral nerve. The postoperative course was uneventful, although the patient needed a walking brace to support her gait. The pathological findings indicated a 99% disappearance of tumor cells. The patient was healthy without any complaints after 1 year of surgery, and a follow-up CT scan revealed no tumor recurrence. Conclusions To the best of our knowledge, this is the first report that showed a nearly complete pathological response to AI in dedifferentiated RPLS, which was subsequently completely resected.

Malignant melanoma (MM) is traditionally known as the “great mime” of human pathology, as it is potentially capable of imitating the most disparate neoplasms. It is known that in addition to the more classic histotypes of MM, there are also rare forms, including angiomatoid MM. Similarly, it has been amply demonstrated in the literature that MM is capable of dedifferentiating, losing melanocytic lineage markers, constituting a diagnostic challenge for the pathologist. Although 5 cases of primary angiomatoid MM have been described in the literature, to the best of our knowledge, no cases of dedifferentiated melanoma with pseudo-angiomatoid aspects have ever been described. In this paper, we present a very rare case of partially dedifferentiated MM in which the most dedifferentiated component lost melanocytic lineage immunohistochemical markers and assumed a pseudo-angiomatous morphology. Given the rarity of the case, we carried out a literature review of similar cases described, trying to draw new future perspectives not only about this particular variant of MM but also about the widest field of dedifferentiation/undifferentiation of MM.

This review provides an overview of histopathology, clinical presentation, molecular pathways, and potential new systemic treatments of high-grade chondrosarcomas (CS), including grade 2–3 conventional, dedifferentiated, and mesenchymal CS. The diagnosis of CS combines radiological and histological data in conjunction with patient clinical presentations. Conventional CS is the most frequent subtype of CS (85%) and represents about 25% of primary bone tumors in adults; they can be categorized according to their bone location into central, peripheral, and periosteal chondrosarcomas. Central and peripheral CS differ at the molecular level with either IDH1/2 mutations or EXT1/2 mutations, respectively. CDKN2A/B deletions are also frequent in conventional CS, as well as COL2A1 mutations. Dedifferentiated CS develops when low-grade conventional CS transforms into a high-grade sarcoma and most frequently exhibits features of osteosarcoma, fibrosarcoma, or undifferentiated pleomorphic sarcoma. Their molecular characteristics are similar to conventional CS. Mesenchymal CS is a totally different pathological entity exhibiting recurrent translocations. Their clinical presentation and management are different too. The standard treatment of CSs is wide en-bloc resection. CS are relatively radiotherapy resistant; therefore, doses >60 Gy are needed in an attempt to achieve local control in unresectable tumors. Chemotherapy is possibly effective in mesenchymal chondrosarcoma and is of uncertain value in dedifferentiated chondrosarcoma. Due to resistance to standard anticancer agents, the prognosis is poor in patients with metastatic or unresectable chondrosarcomas. Recently, the refined characterization of the molecular profile, as well as the development of new treatments, allow new therapeutic options for these rare tumors. The efficiency of IDH1 inhibitors in other malignancies suggests that these inhibitors will be part of IDH1/2 mutated conventional CS management soon. Other treatment approaches, such as PIK3-AKT-mTOR inhibitors, cell cycle inhibitors, and epigenetic or immune modulators based on improving our understanding of CS molecular biology, are emerging.

DEDIFFERENTIATED ENDOMETRIAL CARCINOMA IS A RARE OCCURRENCE IN UTERINE MALIGNANCIES. THIS HISTOPATHOLOGICAL SUBTYPE IS RELATIVELY NEW IN TUMOUR CLASSIFICATIONS AND MOLECULAR ALTERATIONS ARE IN CONTINUOUS DEVELOPMENT. WE DESCRIBE A 61-YEAR-OLD WOMAN WITH THIS DIAGNOSIS ASSOCIATING TWO ENDOMETRIAL POLYPS WITH STROMAL ATYPIA. THIS TYPE OF ASSOCIATION HAS NOT BEEN PREVIOUSLY REPORTED AND DIFFERENTIAL DIAGNOSIS IS OF THE UTMOST IMPORTANCE. WE EXCLUDED OTHER POTENTIAL DIAGNOSES SUCH AS MIXED CARCINOMA OR CARCINOSARCOMA. OUR AIM WAS TO BRING RECOGNITION TO THIS RELATIVELY NEW LESION AND REVIEW THE LITERATURE. [ABSTRACT FROM AUTHOR]

Dedifferentiated central chondrosarcoma (DCCS) is a rare cartilage tumor with invasive biological behavior and a poor prognosis. To better understand the morphological characteristics of this type of tumor and its internal mechanism of dedifferentiation, we retrospectively analyzed 57 cases of DCCS. A total of 29 female and 28 male patients were included, ranging in age from 20 to 76 years, with a median age of 54 years. Fifty-seven cases of DCCS occurred in the pelvis (n = 29), femur (n = 17), scapula (n = 4), tibia (n = 2), humerus (n = 2), metatarsals (n = 1), fibula (n = 1), and radius (n = 1). Radiologically, DCCS had two different appearances on imaging, with an area showing calcifications of the cartilage forming the tumor juxtaposed to a lytic area with a highly aggressive, non-cartilaginous component. Histopathologically, the distinctive morphological features consisted of two kinds of defined components: a well-differentiated cartilaginous tumor and non-cartilaginous sarcoma. The cartilaginous components included grade 1 (n = 38; 66.7%) and grade 2 (n = 19; 33.3%) cartilage. The sarcoma components included those of osteosarcoma (n = 29; 50.9%), undifferentiated pleomorphic sarcoma (n = 20; 35.1%), rhabdomyosarcoma (n = 3; 5.2%), fibrosarcoma (n = 2; 3.5%), spindle cell sarcoma (n = 2; 3.5%) and angiosarcoma (n = 1; 1.8%). Immunohistochemistry showed that the expression of p53 and RB in the sarcoma components was significantly higher than that in the cartilaginous components, suggesting that these factors play roles in the dedifferentiation process of chondrosarcoma. DCCS is a highly malignant tumor with a poor prognosis. Except for the patients who were lost to follow-up, most of our patients died.

De‐differentiated chondrosarcoma (DDCS) is an extremely aggressive tumor of the bone characterized by a high‐grade, non‐chondroid sarcoma adjacent to a low‐ or intermediate‐grade chondrosarcoma. Adequate tumor sampling demonstrating the biphasic features is necessary to make an accurate diagnosis. The diagnosis may be challenging as histopathology may mimic other neoplasms. We present a case of a 76‐year‐old woman with a history of breast cancer who presented with a pathologic non‐displaced fracture. A bone biopsy demonstrated a high‐grade neoplasm composed of pleomorphic spindled and epithelioid cells with focal expression of AE1/3 and GATA3, most likely consistent with metastatic breast carcinoma. After a difficult clinical course, the tumor was resected demonstrating a similar morphology to her prior biopsy, as well as an area of a low‐grade cartilaginous neoplasm consistent with chondrosarcoma. The biphasic tumor alongside a low‐grade chondrosarcoma allowed for a diagnosis of DDCS. Several days after her procedure, the patient developed violaceous nodules overlying and surrounding the surgical site. Skin biopsy demonstrated a malignant epithelioid neoplasm with identical histomorphologic features identical to her prior bone resection. Given the location of the skin lesions directly within the surgical site right after resection, the clinical‐pathological picture was that of sarcomatosis cutis by iatrogenic cutaneous implantation. [ABSTRACT FROM AUTHOR]

Endometrial cancer (EC) is one of the most common gynecologic cancers worldwide. There were 417,367 newly diagnosed cases and 97,370 deaths due to this disease worldwide in 2020. The incidence rates have increased over time, especially in countries with rapid socioeconomic transitions, and EC has been the most prevalent gynecologic malignancy in Taiwan since 2012. The new EC molecular classifications of The Cancer Genome Atlas (TCGA) Research Network include clear-cell carcinoma, serous carcinoma, and carcinosarcoma, while undifferentiated/dedifferentiated EC (UDEC) is not mentioned, and most previous clinical trials for EC have not included UDEC. UDEC is rare, has an aggressive growth pattern, tends to be diagnosed at an advanced stage, and is resistant to conventional chemotherapy. In this review, case series or case reports on the clinical features and genomic/epigenetic and expression profiles on UDEC data are summarized in order to identify potential molecular targets for current and future research.

Liposarcoma is a malignant soft tissue tumor that rarely involves the gastrointestinal tract. The dedifferentiated type typically carries the worst prognosis. Here, we describe a rare case of dedifferentiated liposarcoma of the rectum in a young male patient who was treated with surgical excision. Treatment is often difficult and there is no clear consensus on the benefits of radiotherapy or chemotherapy., (© 2024 The Authors.)

Abstract Background Parosteal osteosarcomas are usually low-grade tumors, however, sometimes they transform to high-grade tumors, which is named dedifferentiation. This phenomenon has been reported in long bones. Recently, we encountered a patient with dedifferentiated parosteal osteosarcoma occurring in the maxilla. Here, we report a first case of dedifferentiated parosteal osteosarcoma of the head and neck region. Case presentation A 45-year-old Japanese woman with a refractory bone lesion in the maxilla presented to our hospital. A biopsy showed atypical spindle cell proliferation involving dedifferentiated high-grade component, which was diagnosed as dedifferentiated parosteal osteosarcoma. Three cycles of neoadjuvant chemotherapy using ifosfamide and pirarubicin were performed followed by sub-total maxillectomy. Histopathological results showed that neoadjuvant chemotherapy was effective for high-grade component. The decision to perform adjuvant chemotherapy (cisplatin and pirarubicin) was made because distant metastasis has been reported, even in cases with dedifferentiated parosteal osteosarcoma in which complete necrosis of high-grade component was achieved due to neoadjuvant chemotherapy. There was no recurrence 15 months after surgery. Conclusions Dedifferentiated parosteal osteosarcoma can occur in the head and neck region. Chemotherapy including anthracycline anticancer agent could be effective for high-grade component of dedifferentiated parosteal osteosarcoma.

Background: Paraneoplastic syndrome is a clinical syndrome with systemic effects, triggered by altered immune response to a neoplasm. Paraneoplastic syndrome was described mostly in association with epithelial malignancies, while in a soft tissue sarcoma it is unusual and hyperleucocytosis as a paraneoplastic phenomenon is very rare. Case presentation: We report a middle aged male patient with bilateral retroperitoneal masses with histomorphology of myxoid liposarcoma with dedifferentiation. Hyper-leucocytosis in the peripheral blood and pronounced myeloid hyperplasia in marrow was found with no obvious focus of infection. There was gradual reduction in white cell count in the postoperative period and reached normal values on Day 8. Hence a diagnosis of dedifferentiated liposarcoma of the retroperitoneum with hyperleucocytosis as a paraneoplastic manifestation was made. Conclusion: Paraneoplastic manifestation could probably be due to production of G-CSF by tumor cells as the leucocytosis disappeared after tumor resection. Further, leucocytosis is not reported in association with well differentiated liposarcoma, and if happens to be so, it might be a clue to search for the dedifferentiated component.

Liposarcomas are malignant mesenchymal neoplasms that, although derived from adipocytes, may dedifferentiate to other cell types. We present an exceedingly rare case of epithelioid/neuroendocrine dedifferentiation with somatostatin expression of a pararenal retroperitoneal liposarcoma. Based on the immunomorphological features, the diagnosis was possible with the support of the molecular FISH investigation: it showed amplification of the MDM2 gene, which is present in most liposarcomas, even in dedifferentiated ones. [ABSTRACT FROM AUTHOR]

Primary dedifferentiated liposarcoma of the orbit is a rare condition. A 41-year-old man presented with a history of right ophthalmalgia with eye movement and exophthalmos that had developed 2 months earlier. Neuroimages revealed a right orbital mass located above the superior rectus muscle. Tumor resection through the right frontal craniotomy was performed. Histopathologic findings showed the dedifferentiated liposarcoma. Primary orbital dedifferentiated liposarcomas remain challenging for their diagnosis and standard treatment. Clinicians should keep in mind the possibility of liposarcoma with orbital tumors. [ABSTRACT FROM AUTHOR]

Liposarcomas are categorized into four distinct histopathological subtypes: atypical lipomatous tumors (ALT)/well‐differentiated liposarcoma (WDL), dedifferentiated, myxoid, and pleomorphic. Dedifferentiated liposarcomas account for approximately 18% of all liposarcomas, characteristically arising in the deep soft tissue. They are reported to have lower rates of metastasis compared to other pleomorphic sarcomas.1–3 The classic histopathologic appearance is ALT/WDL admixed or juxtaposed with a predominantly nonlipogenic sarcoma. Epithelioid features are rare, appearing in as few as 3% of tumors, and have not previously been reported in a superficial location. Herein, we present a 57‐year‐old male with intradermal and subcutaneous metastasis of his known deep dedifferentiated liposarcoma with epithelioid features. By H&E the tumor featured cords and sheets of crowded, plump, epithelioid cells with thick nuclear membranes and prominent nucleoli, which raised a broad differential including carcinoma and melanoma. By immunohistochemistry the tumor was diffusely positive for MDM2 and CDK4, on the other hand stains for Sox10, Melan A, MITF, CKAE1/3, desmin, and S100 protein were negative. This case serves as an opportunity to raise awareness of this rare morphological subtype, which can involve the skin and mimic epithelial and melanocytic malignancies. It can be a potential diagnostic pitfall, especially if metastases are the first presentation. [ABSTRACT FROM AUTHOR]

Background: Retroperitoneal liposarcoma (RPLS) is the most commonly observed soft tissue sarcoma in the retroperitoneal space. Although the beneficial effect of chemotherapy for RPLS is controversial, there are some reports that have shown a considerable tumor-suppressive effect of chemotherapy in RPLS. We demonstrate a case of dedifferentiated RPLS, which was initially considered inoperable but was successfully treated by neoadjuvant chemotherapy and subsequent curative resection. Case presentation: A 59-year-old female was referred to our hospital with a chief complaint of right lower quadrant abdominal pain. Abdominal computed tomography revealed a large retroperitoneal tumor with a maximum diameter of 11 cm. The tumor involved retroperitoneal major vasculatures, such as the right common iliac vein and artery, as well as the right psoas muscle and femoral nerve. The right ureter was also involved and obstructed by the tumor. A biopsy was performed through the retroperitoneal route, and the tumor was diagnosed as a dedifferentiated liposarcoma with the Fédération Nationale des Centres de Lutte Contre le Cancer grade 3. Because the tumor was highly invasive and complete resection was not feasible, we decided to administer neoadjuvant chemotherapy with doxorubicin and ifosfamide (AI). After completing 6 courses of AI, the tumor size was considerably reduced, and we decided to perform surgery with curative intent. Before laparotomy, femoro-femoral arterial bypass was performed to prepare for the right common iliac artery resection. Thereafter, the patient underwent laparotomy and tumor resection combined with right nephrectomy, resection of the right common iliac artery and vein, and resection of the right psoas muscle and femoral nerve. The postoperative course was uneventful, although the patient needed a walking brace to support her gait. The pathological findings indicated a 99% disappearance of tumor cells. The patient was healthy without any complaints after 1 year of surgery, and a follow-up CT scan revealed no tumor recurrence. Conclusions: To the best of our knowledge, this is the first report that showed a nearly complete pathological response to AI in dedifferentiated RPLS, which was subsequently completely resected. [ABSTRACT FROM AUTHOR]

Background: Soft tissue dedifferentiated leiomyosarcoma with heterologous osteosarcomatous component is an extremely rare entity described in only few cases in the literature. Case presentation: We report the case of a 65-year-old male patient who, after initial inadequate surgery of a tumor of the left forearm, developed local recurrence that was treated with neoadjuvant chemotherapy, surgery and postoperative radiation therapy. Histologically the tumor showed an abrupt separation of two different patterns. One component consisted of interlacing fascicles of spindle cells with cigar-shaped nuclei strongly positive for smooth muscle actin, desmin and H-caldesmon. The other component consisted of a high-grade pleomorphic sarcoma with osteoid and chondroid matrix production, which positive for SATB2. Thus, a final diagnosis of dedifferentiated leiomyosarcoma was rendered. Fifteen months after treatment, the patient presented further local and distant relapse with pulmonary metastases and died 23 months after the first presentation. Discussion and conclusions: Dedifferentiated leiomyosarcoma is a highly malignant neoplasm with a poor outcome. Extensive sampling of soft tissue leiomyosarcomas is recommended to detect possible dedifferentiated areas as they represent a crucial prognostic parameter. [ABSTRACT FROM AUTHOR]

Introduction: Dedifferentiated liposarcoma (DDLPS) is defined as a progression of well-differentiated liposarcoma (WDLPS) to another nonlipogenic sarcoma. Since a variety of heterologous sarcomas can be encountered in dedifferentiation, clinical dilemmas arise. The present study analyzed the role of clinicopathologic and immunohistochemical (IHC) features in the diagnosis of DDLPS and its differentiation from mimics. Materials and Methods: A retrospective and prospective study was conducted wherein all cases of liposarcoma from 2012 to 2017 were reviewed. DDLPS cases were identified among pleomorphic lesions. Clinical and histopathological details for these cases were retrieved from medical records section and department archives. Histomorphology and immunohistochemistry (MDM2, S100, and Ki-67) were analyzed for these cases. Results: Among 37 cases of liposarcomas reviewed, DDLPS was diagnosed in 12 cases (32.4%). Mean age of the patients was 54.3 years with equal gender distribution (M:F =1:1.2). Two patients had recurrent tumors. Most were retroperitoneal (58.3%) with mean duration of symptoms being 8.7 months. Mean tumor dimension was 17.5 cm. High-grade dedifferentiated component was most common (83.3%) with only one case each (8.3%) of low-grade and homologous dedifferentiation. Undifferentiated pleomorphic sarcoma was the frequent nonlipogenic sarcoma. MDM2 overexpression was detected in 100%, focal S100 positivity seen in 66.6%, and mean Ki-67 labeling index was 24. Conclusion: DDLPS exhibits aggressive clinical behavior. Adequate sampling, correlation to clinical details, demonstration of transition from WDLPS to DDLPS aid in narrowing the differentials. Immunostaining with MDM2 helps in definite categorization and S100 highlights lipoblasts, when they are not easily identifiable. MDM2, CDK4, and p16 IHC panel is recommended in all cases and fluorescence in situ hybridization analysis where IHC is noncontributory. [ABSTRACT FROM AUTHOR]

We describe the case of a male subject affected by retroperitoneal advanced, anthracycline-pretreated liposarcoma, who experienced a long, beneficial clinical effect from eribulin treatment. In March 2013, a left, paraortic, retroperitoneal mass was surgically removed and diagnosed as Mdm2-positive dedifferentiated liposarcoma. In June 2015, a CT scan revealed disease progression and first-line epirubicin/ifosfamide treatment was started, followed by epirubicin in monotherapy. In January 2017, following a new disease progression, the patient started a second-line eribulin treatment that went on for about 1 year with no major adverse events. The CT scans performed every 3-4 months showed stable disease. After 13 months of treatment, a CT scan revealed disease progression and 10 days later, the patient died of bowel perforation and peritonitis. [ABSTRACT FROM AUTHOR]

Chordomas are rare and low-grade malignant solid tumours, despite their histologically benign appearance, that arise in the bone from embryonic notochordal vestiges of the axial skeleton, a mesoderm-derived structure that is involved in the process of neurulation and embryonic development. Chordomas occurring in the skull base tend to arise in the basiocciput along the clivus. Three major morphological variants have been described (classical, chondroid, and atypical/dedifferentiated). The pathogenesis and molecular mechanisms involved in chordoma development remain uncertain. From a pathological standpoint, the microenvironment of a chordoma is heterogeneous, showing a dual epithelial-mesenchymal differentiation. These tumours are characterised by slow modality of biologic growth, local recurrence, low incidence of metastasis rates, and cancer stem cell (CSC) phenotype. The main molecular findings are connected with brachyury immunoexpression and activation of the downstream Akt and mTOR signalling pathways. The differentiation between typical and atypical chordomas is relevant because the tumoural microenvironment and prognosis are partially different. This review provides an insight into the recent and relevant concepts and histochemical markers expressed in chordomas, with special emphasis on dedifferentiated chordomas and their prognostic implications.

Purpose: We report a case of primitive colonic dedifferentiated liposarcoma along with lymph node metastases. Methods: The patient's clinical, radiologic, surgical, and histologic data were reviewed, as well as the literature on colonic dedifferentiated liposarcoma with a focus on the incidence of lymph node metastasis in gastrointestinal sarcomas and on the differential diagnosis with other spindle cell tumors in the gastrointestinal tract. Results: A 53-year-old man was referred to our hospital with a 3 year-history of pain on the right back that was refractory to drugs. He performed an abdominal computed tomography scan which revealed a colonic wall thickening in the hepatic flexure and a few serosal nodularities. With these findings, the patient underwent an extended right hemicolectomy. On histopathologic examination, it turned out to be a colonic dedifferentiated liposarcoma with lymph node metastases. Conclusions: The present case was a challenging diagnosis both at presurgical and histopathological level because it strongly mimicked a colonic adenocarcinoma. This was due to non-specific clinical and radiological presentation, to the non-characteristic histologic morphology and to the misleading presence of lymph node metastases. Malignant stromal tumors of the gastrointestinal tract beyond gist are fairly rare entities. Colonic dedifferentiated liposarcoma must be kept in mind and must be considered in the differential diagnosis of gastrointestinal tumors. [ABSTRACT FROM AUTHOR]

Solitary fibrous tumor (SFT) is a soft-tissue neoplasm of intermediate malignant potential, presenting a wide histopathological spectrum. Poorer prognosis of hemangiopericytoma of the central nervous system (CNS), hypoglycemic SFT, and dedifferentiation are well-known characters of SFT, but their clinical significance were not demonstrated enough by large-sized study. Here, the clinicopathological features of SFTs are reviewed and the relationship between genetics and clinicopathological features is examined using 145 SFT cases. All cases were STAT6 IHC-positive and/or NAB2-STAT6 fusion gene-positive. Tumor location was classified into three categories: 30 pleuropulmonary, 96 non-pleuropulmonary/non-central nervous system (CNS), and 18 CNS tumors. The tumor developed recurrence in 21 of 93 available cases (22.5%), metastasis in 11 of 93 (11.8%), and tumor death in 9 of 93 (9.6%). Hypoglycemia occurred in 2 primary tumors and 1 metastatic tumor among 63 reviewable cases, and dedifferentiation occurred in 10 cases (6.8%) including 6 primary tumors, 2 recurrent tumors, and 2 metastatic tumors. Recurrence was positively associated with CNS location (p = 0.0109) and hypoglycemia (p = 0.001); metastasis was positively associated with CNS location (p = 0.0231), hypoglycemia (p < 0.0001), and dedifferentiation (p < 0.0001), while metastasis was negatively correlated with pleural location (p = 0.0471). Tumor death was positively associated with male sex (p = 0.0154), larger size (p = 0.0455), hypoglycemia (p < 0.0001), and dedifferentiation (p < 0.0001). Multivariate analysis revealed independent statistical significance of dedifferentiation for overall survival (p = 0.0467). Exon variant of the fusion gene had no statistical correlation with clinical outcome. In conclusion, dedifferentiation is a major prognostic factor of SFT, and specific location such as cerebromeningeal and intra-abdominal site and hypoglycemia also had a high risk for unfavorable prognosis. [ABSTRACT FROM AUTHOR]