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Dermatofibrosarcoma protuberans (DFSP) is a mesenchymal neoplasm that is usually located in the dermis or subcutis and is locally aggressive. Rarely, these lesions may undergo fibrosarcomatous transformation, which is thought to increase their metastatic potential. DFSP is classically associated with a 17;22 translocation (or ring chromosome thereof) resulting in fusion of the COL1A1 and PDGFB genes. However, variant fusions involving PDGFD have been recently reported. Herein, we present two morphologically diverse cases of DFSP with PDGFD rearrangement. Case 1 is a 68-year-old female with a left dorsal foot lesion. Morphologically, the lesion is unusual as it is a well-circumscribed, hypercellular, subcutaneous nodule with uniform CD34-positive spindle cells arranged in a herringbone pattern without storiform arrangement or "honeycombing" fat entrapment. It was diagnosed as pure fibrosarcomatous DFSP. Case 2 is a 37-year-old male with a right supra-auricular lesion. Morphologically, the lesion displays classic DFSP features including bland CD34-positive spindle cells with storiform growth, fat entrapment, and infiltrative borders. Both lesions were negative for COL1A1-PDGFB fusion but positive for PDGFD rearrangement by fluorescence in situ hybridization (FISH) analysis. FISH testing for PDGFD rearrangement should be performed in cases where there is a high suspicion for DFSP but initial studies for COL1A1-PDGFB are negative.

Background Dermatofibrosarcoma protuberans (DFSP) is a superficial fibroblastic tumor characterized by high rate of local recurrence and low metastatic potential. Fibrosarcomatous transformation can rarely arise in DFSP either de novo or as recurrent, which represents a form of tumor progression and carries an increased risk of metastasis over classic DFSP. Cytogenetically, DFSP is characterized by a recurrent unbalanced chromosome translocation t (17;22)(q22;q13), leading to the formation of COL1A1-PDGFB fusion transcript that is present in more than 90% of cases. Alternative fusions involving the PDGFD with partners of COL6A3 or EMILIN2 have recently been documented in less than 2% of cases. Herein, we report a DFSP with fibrosarcomtous morphology harboring a novel TNC-PDGFD fusion. Case presentation A 54-year-old female presented with a slowly growing mass in the right thigh. Excision demonstrated a 2-cm ovoid, well-circumscribed, gray-white, mass. Microscopic examination revealed a partially encapsulated subcutaneous nodule without dermal connection. The neoplasm was composed of cellular and fairly uniform spindle cells with brisk mitoses, arranged in elongated fascicles and herringbone patterns, with focal collagenized stroma. The neoplastic cells were positive for CD34 and smooth muscle actin. Fluorescence in-situ hybridization analyses showed negative for COL1A1-PDGFB fusion as well as NTRK1/2/3 rearrangements. A subsequent RNA sequencing detected an in-frame fusion between exon 15 of TNC and exon 6 of PDGFD. This fusion was further confirmed by nested reverse transcription polymerase chain reaction amplification followed by Sanger sequencing. A diagnosis of fibrosarcomatous DFSP was rendered and the patient was in good status at a follow-up of 12 months after the operation. Conclusions We report a fibrosarcomatous DFSP with novel TNC-PDGFD fusion, which adds to the pathologic and genetic spectrum of PDGFD-rearranged DFSP.

BACKGROUND Dermatofibrosarcoma protuberans (DFSP) is a rare low-grade tumor. Little is known about best treatment of primary and relapsed disease (RD). METHODS Treatment and outcome of 40 patients with DFSP prospectively registered within the CWS-96 and -2002P trials and the registry SoTiSaR (1996-2016) were analysed. RESULTS Median age was 8 years (range, 0.64-17.77). Fluorescence in situ hybridization analysis to detect COL1A1-PDGFB fusion genes was positive in 86% (12/14) of evaluated patients. Primary resection was performed in all patients. Patients had IRS group I (n = 28), II (n = 9), and III (n = 2); not available (n = 1). To achieve complete remission (CR), a secondary resection was performed in 18 patients resulting in microscopically complete (R0, n = 34/40) and microscopically incomplete (R1, n = 5/40) resection. All patients achieved CR. The 5-year event-free survival (EFS) and overall survival was 86% (±12; CI, 95%) and 100% (±0; CI, 95%), respectively. R0 resection/IRS I was significantly favorable for the 5-year EFS. Local relapse occurred after a median time of 1.1 years (range, 0.04-5.1) in 15% (6/40) after CR. All patients with RD underwent resection and achieved CR. Three patients had fibrosarcomatous DFSP, two were alive after R0 resection. CONCLUSION Complete surgical resection is mandatory to prevent relapse of DFSP.

Introduction: Dermatofibrosarcoma protuberans (DFSP) is an intermediate and slow-growing sarcoma, arising most commonly in the trunk and extremities and rarely in the breast. It may be recurrent, but metastasis is rare. Excision with good resection margins reduces the rate of recurrence. Case Presentation: A 28-year-old lady presented with a painless lump in the left breast of 16 years duration. Examination revealed an ulcerated firm mass, well defined, with perilesional nodules on the skin of the breast. Wedge biopsy favoured Borderline Phylloides Tumour over DFSP. Patient was offered mastectomy and the histology of the specimen confirmed Fibrosarcomatous DFSP. Conclusion: This stresses the importance of histology in diagnosing a rare breast tumour. This is very important because it may show similar appearance to other benign and malignant breast lesions, which makes clear the role of pathological investigation to make a definitive diagnosis.

Objectives: To conduct a descriptive clinicopathological and demographic analysis of dermatofibrosarcoma protuberans among Saudi patients attending a tertiary care center in the eastern province of Saudi Arabia. Methods: This retrospective, single-center study reviewed the medical records and pathology reports of Saudi patients attending a tertiary center (Johns Hopkins Aramco Health Care) in Dhahran, Saudi Arabia from 1995 to 2019 to identify all cases of dermatofibrosarcoma protuberans. Demographic and phenotypic data were also analyzed. Results: Thirty-five Saudi patients were identified as having dermatofibrosarcoma protuberans. Females constituted 68.6% of patients. The trunk was the most common site of involvement (54.3%), followed by the lower extremities (34.3%), upper extremities (8.6%), and head and neck (2.9%). The mean tumor size was 2.9 cm (standard deviation: ±2.0). There was only one case of distant metastasis of fibrosarcomatous dermatofibrosarcoma protuberans. Conclusions: Dermatofibrosarcoma protuberans was not frequently encountered in Saudi patients in a tertiary center that treats approximately 187,668 patients. Dermatofibrosarcoma protuberans disease patterns and demographic data were similar to those reported worldwide. Further studies are required to characterize dermatofibrosarcoma protuberans in the Saudi population.

Aim: Dermatofibrosarcoma protuberans (DFSP) accounts for less than 2% of all soft-tissue sarcomas. Patients & methods: We retrospectively reviewed our database for patients with locally advanced or metastatic DFSP who had presented to our clinic between January 2016 and January 2020. Results: We identified a total of 14 patients, of whom ten had sarcomatous transformation. Eleven cases had metastatic disease and three were locally advanced. The initial partial response rate to first-line imatinib was 76.9% and the overall median progression-free survival on imatinib was 15 months. Conclusion: We had a high proportion of patients with sarcomatous transformation, in contrast to their relative rarity in the West. While most patients had initial good responses to imatinib, second-line therapies were not as effective., Lay abstract Dermatofibrosarcoma protuberans is a rare sarcoma. Most patients have localized disease that can be cured by surgery alone. In those cases where either surgery is not possible or the disease is already metastatic, oral imatinib is the treatment of choice. In this article, we describe our experience with imatinib in such cases. Although most patients do well on imatinib, at least initially, many develop resistance to the drug. There are no established evidence-based therapies for patients who progress on imatinib, and as we describe in our paper, most of our patients did not do well on second-line medications.

Dermatofibrosarcoma protuberans (DFSP) is a translocation-associated, low-grade sarcoma with fibroblastic differentiation. It is the most common superficial sarcoma, almost exclusively arising within the dermis. In a minority of cases, there is a transition from the conventional morphology to a fibrosarcomatous pattern, known as a fibrosarcomatous DFSP (FS-DFSP). Although a number of different molecular alterations have been described to account for this transformation, it remains poorly understood. Herein we report the first case of a FS-DFSP with a fusion between ERG, an ETS family transcription factor, and MAP3K7CL, a kinase gene rarely observed in fusion gene events.

BackgroundFibrosarcomatous dermatofibrosarcoma protuberans (FS-DFSP) is a form of tumor progression of dermatofibrosarcoma protuberans (DFSP) with an increased risk of metastasis and recurrence. Few studies have compared the clinicopathological features of FS-DFSP and conventional DFSP (C-DFSP).ObjectivesTo better understand the epidemiological and clinicopathological characteristics of FS-DFSP.MethodsWe conducted a cohort study of 221 patients diagnosed with DFSP and built a recognition model with a back-propagation (BP) neural network for FS-DFSP.ResultsTwenty-six patients with FS-DFSP and 195 patients with C-DFSP were included. There were no differences between FS-DFSP and C-DFSP regarding age at presentation, age at diagnosis, sex, size at diagnosis, size at presentation, and tumor growth. The negative ratio of CD34 in FS-DFSP (11.5%) was significantly lower than that in C-DFSP (5.1%) (P = 0.005). The average Ki-67 index of FS-DFSP (18.1%) cases was significantly higher than that of C-DFSP (8.1%) cases (P ConclusionsThe clinical manifestations of FS-DFSP and C-DFSP are similar but have large differences in immunohistochemistry. The classification accuracy and feasibility of the BP neural network model are high in FS-DFSP.

BACKGROUND Dermatofibrosarcoma protuberans (DFSP) is a rare low-grade tumor that typically does not metastasize but often recurs. Fibrosarcomatous DFSP (FS-DFSP) is associated with a substantially higher rate of metastasis and a poorer prognosis. OBJECTIVE This study sought to investigate the epidemiological, histopathological, and clinical characteristics of DFSP, especially with a particular focus on FS-DFSP. MATERIALS AND METHODS Clinical data from 254 patients treated between January 1999 and July 2018 were retrospectively reviewed. Endpoints of the study were the incidence of significant disease-related clinical events. RESULTS Follow-up data from 211 patients were available for analysis, with a median follow-up time of 38 months (range: 1-196 months). The 5-year recurrence-free survival rate of patients underwent wide-local excision (WLE) was 97.1%. Patients underwent WLE exhibited a significantly decreased recurrence rate relative to patients treated through local excision (2.9% vs 37.7%; p < .001). Fibrosarcomatous DFSP had significantly higher rates of distant metastasis (66.7% [n = 4] vs 2.0% [n = 4]; p < .001) and long-term mortality (50.0% [n = 3] vs 1.5% [n = 3]; p < .001), compared with classical DFSP (C-DFSP). CONCLUSION Wide-local excision is an effective means of reducing DFSP recurrence. Rates of metastasis are higher for FS-DFSP than for C-DFSP, with the former having significantly poorer outcomes.

Fibrosarcomatous transformation of dermatofibrosarcoma protuberans (DFSP) is a rare variant with higher risk of recurrence and metastasis, and no known associations with breast implants. We report a rare case of fibrosarcomatous dermatofibrosarcoma protuberans arising at the site of breast implant in a 33-year-old patient followed by brief discussion on fibrosarcomatous DFSP.

The diagnosis of malignant peripheral nerve sheath tumors can be challenging and other spindle cell sarcomas commonly enter in the differential diagnosis. Loss of trimethylation at lysine 27 of histone-H3 (H3K27me3) by immunohistochemistry was recently described in malignant peripheral nerve sheath tumors. However, its specificity remains controversial. We therefore studied 82 synovial sarcomas, 39 malignant peripheral nerve sheath tumors, and 10 fibrosarcomatous dermatofibrosarcoma protuberans for H3K27me3 loss by immunohistochemistry. The diagnoses were based on morphology, immunophenotype, and genetics based on WHO classification. H3K27me3 immunohistochemistry was scored by two pathologists based on fraction of cells with nuclear staining (score 0 to 3+). Loss of H3K27me3 (score 0) was seen in 44% of malignant peripheral nerve sheath tumors and 9% of synovial sarcomas yielding positive and negative predictive values of 71% and 77%, respectively. Loss of H3K27me3 was seen in 10% of fibrosarcomatous dermatofibrosarcoma protuberans, yielding positive and negative predictive values of 94 and 29% in the differential diagnosis of malignant peripheral nerve sheath tumor versus fibrosarcomatous dermatofibrosarcoma protuberans. Partial loss (score 1-2) was common in all three tumor types. Among malignant peripheral nerve sheath tumors, there was no significant association between H3K27me3 loss and gender, tumor site, or size, and progression-free or overall survival. Patients with tumors with H3K27me3 loss were younger than those with tumors with retained H3K27me3 expression (P=0.011). H3K27me3 expression was lost in 50 and 31% of sporadic and Neurofibromatosis-associated malignant peripheral nerve sheath tumors, respectively (P=0.25).Complete H3K27me3 loss is a moderately sensitive and relatively specific marker for the diagnosis of malignant peripheral nerve sheath tumor when the differential diagnosis includes synovial sarcoma and fibrosarcomatous dermatofibrosarcoma protuberans. Partial loss has limited diagnostic utility. H3K27me3 status does not show significant association with clinical outcome in malignant peripheral nerve sheath tumors.

Dermatofibrosarcoma protuberans (DESP) is a relatively rare and low-grade tumor of the skin and soft tissue. We review the clinical features, pathological findings and management of recurrent DESP with the aim to improve our understanding of this rare tumor. Fifty-seven patients were diagnosed with recurrent DFSP. The mean age at the presentation of DFSP was 30.9 years. The mean age at diagnosis of DFSP was 40.2 years. Chest wall was the dominant location. The histopathological diagnosis was ordinary DFSP (O-DFSP) in 46 cases and fibrosarcomatous DFSP (FS-DFSP) in 11 cases. No differences were noted between FS-DFSP and conventional DFSP in age at presentation and diagnosis, tumor size, as well as CD34 and SMA expression (P > 0.05). However, the time course to recurrence in FS-DFSP group was less than that in O-DFSP group (P = 0.038). All of the patients were treated with Mohs micrographic surgery (MMS). On follow-up, none of the patients had tumor recurrence. Our data demonstrated that the clinical features of recurrent DFSP are non-specific and variable. Our current practice suggests that MMS is very useful treatment choice for recurrent DFSP.

Several uncommon variants of dermatofibrosarcoma protuberans (DFSP) and the limitations of small biopsies render pathological diagnosis difficult. The aim of this study was to analyze the utility of fluorescence in situ hybridization (FISH) in the detection of the collagen type I-α1/platelet derived growth factor-β (COL1A1-PDGFB) fusion gene in biopsies of DFSP. Twenty-three consecutive biopsy specimens of DFSP were reviewed for clinicopathological features and examined with the COL1A1-PDGFB fusion probe and PDGFB break-apart probe using FISH analysis. The 23 tumor samples consisted of 11 males and 12 females (mean age at diagnosis, 37 years; range, 14-75 years). Eighteen conventional DFSP, one Bednar tumor, two myxoid DFSP and two fibrosarcomatous DFSP samples were included in the group. Strong and extensive CD34 expression was observed in 19 of 23 cases (83%). Twenty-one cases (91%) were positive for both the COL1A1-PDGFB fusion signal and the PDGFB break-apart signal. This is one of the few studies to demonstrate the value of FISH analysis of the COL1A1-PDGFB gene, which could validate complicated and suspected diagnoses in the routine biopsy of DFSP.

Dermatofibrosarcoma protuberans (DFSP) is a dermal sarcoma often diagnosed by excision biopsy, and is often incompletely excised, with high recurrence rates. Traditional wide excision involves resection margins of 2–4 cm, often resulting in morbid procedures requiring surgical reconstruction. An alternative is conservative re-excision (CRE), which results in narrower margins and less-frequent reconstruction. The aim of this study is to assess the effectiveness of CRE in providing local control. A retrospective review of patients treated for DFSP at a tertiary sarcoma centre over a 10-year period. Ninety-eight patients were analysed. Median follow-up was 53 months. Fifty-four patients had microscopically incompletely excised DFSP, and of these, 41 underwent CRE of DFSP scar. Seven (17.1%) patients required more than one CRE to achieve negative margins. The mean width of CRE was 15.4 mm. Fifty-four patients had resection of intact tumours, with 19 (35.2%) requiring surgical reconstruction. One patient (1%) developed local recurrence, and one patient (1%) distant recurrence—both of these patients had high-grade fibrosarcomatous DFSP. No patient with classical DFSP who had clear margins sustained recurrence, regardless of whether their surgery was CRE of scar or wide excision of tumour. CRE is a safe and acceptable alternative to traditional wide excision, with no patients developing local recurrence (LR). CRE results in low rates of surgical reconstruction, and hence lower morbidity; this is partially offset by the higher rates of inadequate excision requiring further surgery. However, the lesser rate of inadequate excision compared with rates of reconstruction makes CRE an attractive option.

Dermatofibrosarcoma protuberans (DFSP) is soft tissue malignancy which is locally aggressive, slow-growth, rarely metastasizing but recurs frequently after surgical excision. Fibrosarcomatous dermatofibrosarcoma protuberans (FS-DFSP) is a variant of DFSP with a higher risk of recurrence and metastasis. For treatment of metastatic DFSP, antiangiogenesis therapy is an important therapeutic option, which is beneficial in increasing the efficacy of chemotherapy. Apatinib is a novel vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitor and revealed potential anti-tumor efficacy in some types of sarcomas. However, there is still no report of apatinib as an angiogenesis therapy for metastatic DFSP to date. Herein we first describe a case of FS-DFSP relapsed and metastasized post multiple surgeries and adjuvant radiotherapy responded to apatinib in combination with chemotherapy, indicating apatinib may be a potential therapeutic option for metastatic DFSP.

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue neoplasm of low metastatic potential notable for its progressive growth and high rate of local recurrence after surgical excision. Fibrosarcomatous transformation of DFSP (FS-DFSP) is a rare variant characterized by higher rates of local recurrence and metastasis. Trauma has been hypothesized as a potential risk factor for the development of DFSP, although clear evidence has been lacking. In this study, we report a case of FS-DFSP that was found arising from a previously stable scar following a traumatic injury. A 49-year-old male was diagnosed with keloid scars following a motor vehicle accident where he sustained trauma. 12 years later, a large tumor developed immediately after a second traumatic event to the primary scar. Pathology of the excisional biopsy specimen demonstrated FS-DFSP with focal areas consistent with keloid and hypertrophic scar. This observation demonstrates the development of DFSP from underlying scar following a clear history of trauma. Furthermore, it suggests trauma as a possible trigger for the fibrosarcomatous transformation of DFSP.

Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous tumor with a high incidence of misdiagnosis. DFSP has a high rate of recurrence but a low rate of metastasis. In the present study, retrospective analyses were performed on the clinical features, differential diagnosis and treatment of patients with DFSP to improve our understanding of the disease and allow more effective treatment measures to be implemented. The present study investigated the clinicopathological features of 70 pathologically confirmed cases of DFSP at the First Affiliated Hospital of Zhengzhou University (Zhengzhou, China) between March 2012 and 2017. The primary endpoint was recurrence rate. Three cases were analyzed in detail. The results revealed that 7 of the 41 primary patients (follow-up at 2.7 years) had recurrence (17.1%), compared with 11 (37.9%) of the 29 recurrent patients (follow-up at 2.0 years, P=0.049). Of the 59 patients with DFSP (follow-up at 2.6 years), 12 had recurrence (20.3%) compared with 6 (54.6%) of the 11 patients with fibrosarcomatous DFSP (FS-DFSP; follow-up at 2.1 years, P=0.045). DFSP requires diagnosis by pathological examination, and surgical resection is the main treatment. DFSP demonstrated a high recurrence rate, with the degree of malignancy increasing following multiple recurrences. FS-DFSP had a higher risk of local recurrence and distant metastasis, and a higher degree of malignancy than classic DFSP. These data may be useful to guide clinicians to improve decisions in the treatment of patients with DFSP.

Dermatofibrosarcoma protuberans (DFSP) is an aggressive PDGFB-dependent cutaneous sarcoma characterized by infiltrative growth and frequent local recurrences. Some DFSP progress to a higher-grade fibrosarcomatous form, with rapid growth and increased risk of metastasis. Imatinib provides clinical benefit in approximately 50% of patients with unresectable or metastatic DFSP. However, efficacious medical therapies have not been developed for imatinib-resistant DFSP. We established a model of imatinib-resistant DFSP and evaluated CDK4/6 inhibition as a genomically credentialed targeted therapy. DFSP105, an imatinib-resistant human cell line, was established from a fibrosarcomatous DFSP (FS-DFSP), and was studied by SNP arrays and sequencing to identify targetable genomic alterations. Findings were validated in vitro and in vivo, and confirmed in a series including 12 DFSP and 6 FS-DFSP. SNP analysis of DFSP105 revealed a homozygous deletion encompassing CDKN2A and CDKN2B. The resultant p16 loss implicated CDK4/6 as a potential therapeutic target in DFSP. We further demonstrated CDKN2A homozygous deletion in 1 of 12 conventional DFSP and 2 of 6 FS-DFSP, whereas p16 expression was lost in 4 of 18 DFSP. In vitro treatment of DFSP105 with two structurally distinct selective CDK4/6 inhibitors, PD-0332991 and LEE011, led to inhibition of RB1 phosphorylation and inhibition of proliferation (GI50 160 nmol/L and 276 nmol/L, respectively). In vivo treatment of DFSP105 with PD-0332991 (150 mg/kg) inhibited xenograft growth in mice, in comparison with imatinib-treated or -untreated tumors. In conclusion, CDKN2A deletion can contribute to DFSP progression. CDK4/6 inhibition is a preclinically effective treatment against p16-negative, imatinib-resistant FS-DFSP, and should be evaluated as a therapeutic strategy in patients with unresectable or metastatic imatinib-resistant DFSP. Mol Cancer Ther; 14(6); 1346–53. ©2015 AACR.

Dermatofibrosarcoma protuberans (DFSP) is a cutaneous tumor of intermediate-grade malignant potential, and it rarely shows dedifferentiation to high-grade fibrosarcoma, which is called "fibrosarcomatous DFSP." We present the enhanced MRI and PET/MRI findings and our comparison with pathological findings in a case of fibrosarcomatous DFSP with various histological features.

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas that can show overlapping features with benign neurofibromas as well as high-grade sarcomas. Additional diagnostic markers are needed to aid in this often challenging differential diagnosis. Recently mutations in two critical components of the polycomb repressor 2 (PRC2) complex, SUZ12 and EED, were reported to occur specifically in MPNSTs while such mutations are absent in neurofibromas, both in the setting of neurofibromatosis (NF) and sporadic cases. Furthermore, both SUZ12 and EED mutations in MPNSTs were associated with loss of H3K27 tri-methylation, a downstream target of PRC2. Therefore, we tested whether H3K27me3 immunohistochemistry is useful as a diagnostic and prognostic marker for MPNSTs. We performed H3K27me3 immunohistochemistry in 162 primary MPNSTs, 97 neurofibromas and 341 other tumors using tissue microarray. We observed loss of H3K27me3 in 34% (55/162) of all MPNSTs while expression was retained in all neurofibromas including atypical (n=8) and plexiform subtypes (n=24). Within other tumors we detected loss of H3K27me3 in only 7% (24/341). Surprisingly, 60% (9/15) of synovial sarcomas and 38% (3/8) of fibrosarcomatous dermatofibrosarcoma protuberans (DFSP) showed loss of H3K27 trimethylation. Only 1 out of 44 schwannomas showed loss of H3K27me3 and all 4 perineuriomas showed intact H3K27me3. Furthermore, MPNSTs with loss of H3K27 tri-methylation showed inferior survival compared with MPNSTs with intact H3K27 tri-methylation, which was validated in two independent cohorts. Our results indicate that H3K27me3 immunohistochemistry is useful as a diagnostic marker, in which loss of H3K27me3 favors MPNST above neurofibroma. However, H3K27me3 immunohistochemistry is not suitable to distinguish MPNST from its morphological mimicker synovial sarcoma or fibrosarcomatous DFSP. Since loss of H3K27 tri-methylation was related to poorer survival in MPNST, chromatin modification mediated by this specific histone seems to orchestrate more aggressive tumour biology.

The myxoid variant of dermatofibrosarcoma protuberans (DFSPs) is uncommon. It often presents a diagnostic challenge and is important to recognize to prevent both undertreatment and overtreatment. To better characterize this unusual variant of DFSP, 23 myxoid DFSPs (DFSP with greater than 50% myxoid stroma) were retrieved from the authors' consult files. 13 patients were male and 10 were female (median age 40 years; range 9 months to 72 years of age). Tumor size ranged from 1.5 to 11 cm (median 2.8 cm). The most frequent sites were the extremities (9) and head and neck (7), followed by the trunk (4) and anogenital region (3). Grossly, the tumors were white/tan/gray to yellow, firm to gelatinous soft tissue masses. Histologically, tumor stroma ranged from 50 to 100% myxoid (median 80%). The majority of cases displayed an infiltrative sheet-like proliferation of bland spindle cells with palely eosinophilic cytoplasm and stellate nuclei without pleomorphism. The stroma was myxoid with prominent thin-walled vessels. All cases displayed honeycomb infiltration of fat and 16 cases showed cellular areas of more typical DFSP. Four tumors contained pigmented dendritic cells (Bednar variant), 1 showed areas of giant cell fibroblastoma and 1 showed progression to fibrosarcomatous DFSP. Mitoses ranged from 0 to 5 per 10 high power fields. 95% of cases (21 out of 22) were positive for CD34 and all cases were negative for S100 and muscle markers. Clinical follow-up in 8 cases, ranging from 3-21 years, (median follow-up 6 years), revealed local recurrence in 2 cases and no evidence of metastasis. All patients were free of disease following wide excision or excision followed by radiotherapy. In summary, these low-grade lesions are clinically similar to typical DFSP, but their unusual morphology is easily confused with a variety of other tumor types.

Dermatofibrosarcoma protuberans (DFSP) is a rare, plaque-like tumor of the cutaneous tissue occurring more on the trunk than the extremities and neck. More than 95% of DFSP present anomalies on the 17q22 and 22q13 chromosomal regions leading to the fusion of COL1A1 and PDGFB genes. Surgery is the optimal treatment for DFSP, but less effective in locally advanced or metastatic patients, as is the case with chemotherapy and radiotherapy. The aim of this study was to assess retrospectively the therapeutic activity and safety of imatinib on 22 Chinese patients with locally inoperative or metastatic DFSP at a single institution. In the collected data of 367 Chinese patients with DFSP, we analyzed retrospectively 22 patients with locally advanced or metastatic DFSP, all of whom received imatinib therapy at 1 center from January 2009 to October 2014. Patients were administered with imatinib at an initial dose of 400 mg and escalated to 800 mg daily after they developed imatinib resistance. The median follow-up time was 36 months, and the median treatment time was 15 months. The results showed that 10 locally advanced DFSP patients and 12 metastatic DFSP patients received imatinib therapy. Apart from 1 patient who developed primary imatinib resistance, 15 patients achieved partial remission (PR), and 6 patients achieved stable disease (SD). Both fibrosarcomatous DFSP and classic DFSP patients demonstrated similar response to imatinib. Median PFS was estimated to be 19 months. Median overall survival (OS) has not been reached, and estimated 1- and 3-year OS rates were 95.5% (21/22) and 77.3% (17/22), respectively. Four out of 10 patients with primarily unresectable DFSP received complete surgical resection after neoadjuvant treatment of imatinib. Imatinib therapy is well tolerated with a safety profile and is the therapy of choice in locally inoperative or metastatic DFSP. Neoadjuvant treatment of locally advanced or metastatic DFSP with imatinib improves surgical outcomes and may facilitate resection of difficult tumors.

Dermatofibrosarcoma protuberans (DFSP) is a skin fibroblastic tumour that is locally aggressive, with a tendency for local recurrence, but rarely metastasizes. A unique collaboration of multi-disciplinary experts from the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO) and the European Organization of Research and Treatment of Cancer (EORTC) was formed to make recommendations on DFSP diagnosis and treatment, based on systematic literature reviews and the experts' experience. Diagnosis is suspected clinically and confirmed by pathology. Analysis by fluorescence in situ hybridisation (FISH) or multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) to detect specific chromosomal translocations and fusion gene transcripts is useful to confirm a difficult DFSP diagnosis. Treatment is mainly surgical, with the aim to achieve complete resection of the tumour. In order to reduce the recurrence rate, the treatment of choice of DFSP seems to be Mohs' micrographic surgery (MMS) and related variants. In hospitals where only standard histopathological procedures are available, standard excision with lateral safety margin of 3cm is advisable. Imatinib (Glivec®) is approved in Europe for the treatment of inoperable primary tumours, locally inoperable recurrent disease, and metastatic DFSP. Imatinib has also been given to patients with extensive, difficult-to-operate tumours for preoperative reduction of tumour size, but the usefulness of this attitude should be confirmed by clinical trials. Therapeutic decisions for patients with fibrosarcomatous DFSP should be primarily made by an interdisciplinary oncology team ('tumour board').

Dermatofibrosarcoma protuberans (DFSP) typically affects the dermis and subcutaneous tissue. The subcutaneous variant is rare.We sought to characterize the subcutaneous DFSP (SC-DFSP) variant and compare it with cutaneous DFSP (C-DFSP).This work was a retrospective study of DFSP treated in our institution.Of 124 cases of DFSP, 18 were SC-DFSP (14.5%). Except for the deep location, the pathologic and genetic features were indistinguishable from the C-DFSP variant. Histologically, of 18 SC-DFSP cases, 13 were classic DFSP, 3 fibrosarcomatous DFSP (FS-DFSP), 1 Bednar tumor, and 1 giant-cell fibroblastoma. All tumors expressed CD34 and the COL1A1-PDGFB fusion transcripts. In our series, higher proportions of SC-DFSP tumors (61%) than C-DFSP tumors (8.5%) were located on the head (P .001). Of the 20 DFSP tumors on the head (16.1%), 11 were SC-DFSP and 9 were C-DFSP. In addition, half the SC-DFSP tumors affected muscle or periosteum, compared with a quarter of the C-DFSP tumors (P = .009). SC-DFSP needed a higher number of Mohs stages than did C-DFSP (P = .009). Median follow-up time was 63 months, and 2 FS-DFSP tumors recurred (1 SC-DFSP, 1 C-DFSP).Limitations include the retrospective aspect of the study.Most DFSP tumors involving the head were subcutaneous and required more complex surgery. Dermatologists should be aware of this atypical presentation, especially in lesions involving the head.

Background Despite optimal surgical therapy for patients with dermatofibrosarcoma protuberans (DFSP), some patients still continue to develop local recurrence. The authors' objective was to identify and analyze clinicopathologic factors for disease free survival in a large group of patients who were followed prospectively at a single institution. Methods Prospectively collected data and pathology slides were available for review from 159 patients with primary or recurrent DFSP who underwent treatment between July 1950 and July 1998. The study group was comprised of patients with either the "classic" form of DFSP or the fibrosarcomatous "high grade" variant of DFSP (FS-DFSP). Patient, tumor, pathologic, and treatment factors were analyzed using the log rank test for univariate influence and Cox regression analysis for multivariate influence. Local recurrence free survival was determined by the Kaplan-Meier actuarial method. Results Of the 159 patients who comprised the current study group, 134 (84%) had the classic form of DFSP. The FS-DFSP variant was found in the remaining 25 patients (16%). The overall 5-year local recurrence free survival rate was 75%, with a median follow-up of 4. 75 years. The 5-year recurrence free survival rate for each group was 81% and 28%, respectively. On univariate analysis, age > 50 years, very close ( Conclusions The prognosis after surgical resection with negative and sometimes positive microscopic margins for patients with DFSP is very good. However, increased age, high mitotic index, and increased cellularity are predictors of poor clinical outcome. The FS-DFSP variant represents a much more aggressive tumor with metastatic potential. Patients who are treated with curative intent for FS-DFSP should undergo aggressive attempts at complete surgical resection. Patients with recurrent classic DFSP without evidence of adverse prognostic features may benefit from conservative management, especially in the setting of potentially unresectable disease.

We discuss a metastatic dermatofibrosarcoma protuberans on the occiput of a 53-year-old man whose initial tumor appeared on his forehead 23 years previously. The pathology of the tumor that recurred at the initial site was fibrosarcomatous dermatofibrosarcoma protuberans, whereas the metastatic tumor was a pigmented dermatofibrosarcoma protuberans, the so-called Bednar tumor. Because both tumors possessed the identical chimeric COL1A1-PDGFB fusion gene, the metastatic nature of the occipital tumor was confirmed.

Dermatofibrosarcoma protuberans (DFSP) is a relatively rare low-grade sarcoma that occasionally exhibits melanin-containing spindle cells within the tumor. Fibrosarcomatous DFSP (FS-DFSP) is a variant that is characterized by areas which are histopathologically indistinguishable from fibrosarcoma. In the present study, we describe a case of fibrosarcomatous pigmented DFSP and review the clinicopathological features of this extremely rare lesion. A 51-year-old male presented with a slow-growing nodular cutaneous mass in his left upper arm. Histopathologically, the resected tumor was comprised of pigmented DFSP in approximately 20% of the tumor, with the remaining area further covered by a fibrosarcomatous component. A review of the clinicopathological features of the five previously reported cases as well as the present case indicated that this lesion mainly affects middle-aged males and occurs mostly in the extremities. Melanin-containing spindle cells are present only in the conventional DFSP component. The prognosis appears to be poor; in the six cases reviewed, four demonstrated multiple metastases and three succumbed to the disease. Our analyses revealed that the presence of a fibrosarcomatous component in pigmented DFSP is associated with aggressive behavior; therefore, careful assessment for the presence of a fibrosarcomatous component is necessary in the diagnosis of this disease.

Dermatofibrosarcoma protuberans (DFSP) is characterized by the presence of the t(17;22)(q22;q13) that leads to the fusion of the COL1A1 and PDGFB genes. This translocation can be detected by multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) or fluorescence in situ hybridization (FISH) techniques. We have evaluated the usefulness of a dual color dual fusion FISH probe strategy for COL1A1/PDGFB detection in a series of 103 archival DFSPs and compared the obtained results with RT-PCR analyses. FISH and RT-PCR were carried out on paraffin embedded tissue samples. Regarding the RT-PCR approach, all COL1A1 exons and exon 2 of PDGFB were evaluated. Sensitivity, specificity, positive and negative predictive values were assessed considering the histological diagnosis as the gold standard. We also analyzed the relationship between the genetic findings and the clinicopathological variables of the tumors. The COL1A1/PDGFB translocation was detected in 93% of DFSP. Both techniques showed a similar specificity (100%), but FISH was more sensitive than RT-PCR (90% vs. 72%). Regarding, clinicopathological features, a higher percentage of positive cells detected by FISH was significantly associated with the fibrosarcomatous DFSP variant (P < 0.001). Interestingly, all CD34 negative DFSP (n = 5) were positive for COL1A1/PDGFB translocation by both techniques. In conclusion, the majority of DFSP harbor the COL1A1/PDGFB translocation and FISH technique should be recommended as a routine diagnostic tool, especially in cases showing unusual histopathological subtypes and/or immunohistochemical features., Supported by: RTICCs; Beca Jose Ma Buesa from Grupo GEIS de Ayuda a la Investigación en Sarcomas sponsored by Novartis, and Grants RETICs RD07/0020/2004 and RD02/0020/0059 from Instituto de Salud Carlos III (ISCIII), Spanish Ministry of Science and Innovation, European Regional Development Fund (ERDF) ‘‘Una manera de hacer Europa’’.

Purpose Dermatofibrosarcoma protuberans (DFSP) is a dermal sarcoma typically carrying a translocation between chromosomes 17 and 22 that generates functional platelet-derived growth factor B (PDGFB). Patients and Methods Two distinct phase II trials of imatinib (400 to 800 mg daily) in patients with locally advanced or metastatic DFSP were conducted and closed prematurely, one in Europe (European Organisation for Research and Treatment of Cancer [EORTC]) with 14-week progression-free rate as the primary end point and the other in North America (Southwest Oncology Group [SWOG]) with confirmed objective response rate as the primary end point. In the EORTC trial, confirmation of PDGFB rearrangement was required, and surgery was undertaken after 14 weeks if feasible. The SWOG study confirmed t(17;22) after enrollment. Results Sixteen and eight patients were enrolled onto the EORTC and SWOG trials, respectively. Tumor size ranged from 1.2 to 49 cm. DFSP was located on head/neck, trunk, and limb in seven, 11, and six patients, respectively, and was classic, pigmented, and fibrosarcomatous DFSP in 13, one, and nine patients, respectively. Metastases were present in seven patients (lung involvement was present six patients). Eleven patients (4%) had partial response as best response, and four patients had progressive disease as best response. Median time to progression (TTP) was 1.7 years. Imatinib was stopped in 11 patients because of progression, one patient because of toxicity, and two patients after complete resection of disease. Median overall survival (OS) time has not been reached; 1-year OS rate was 87.5%. Conclusion Imatinib is active in DFSP harboring t(17;22) including fibrosarcomatous DFSP, with objective response rate approaching 50%. Response rates and TTP did not differ between patients taking 400 mg daily versus 400 mg twice a day.

Soft-tissue sarcomas can be divided into translocation-associated (TA) and non-TA sarcomas, the latter of which is often characterized by pleomorphic cytomorphology and aneuploidy. The aberrant expression of MAD2, an essential component of the mitotic spindle checkpoint, has been recently shown to promote aneuploidy. The aim of the present paper was to assess MAD2 status on immunohistochemistry in 50 TA sarcomas with known fusion genes and 50 non-TA pleomorphic sarcomas. MAD2 was overexpressed in 26 TA (52%) and 33 non-TA sarcomas (66%). Notably, the MAD2 overexpression was frequently detected in TA sarcomas with atypical or high-grade morphology, such as round cell liposarcoma and fibrosarcomatous dermatofibrosarcoma protuberans. The MAD2 overexpression was significantly frequent in non-TA sarcomas compared with TA tumors without such atypical or high grade morphology (P = 0.012). In addition, sarcomas with MAD2 overexpression were significantly rich in abnormal mitotic figures, including multipolar mitoses and anaphase bridges, compared to MAD2-negative tumors (P = 0.003), although the overall mitotic activity was equivalent between the sarcomas with or without the MAD2 overexpression. These data suggest that the aberrant MAD2 expression is potentially associated with pleomorphic morphology and abnormal mitosis in soft-tissue sarcomas, as well as with high-grade tumor progression in its TA subset.

Dermatofibrosarcoma protuberans (DFSP) is an aggressive PDGFB-dependent cutaneous sarcoma characterized by an infiltrative growth and high rate of local recurrence. Some DFSP progress to a higher-grade fibrosarcomatous form, with rapid growth and increased risk of metastasis. Imatinib provides clinical benefit in ∼50% of patients with unresectable or metastatic DFSP. Efficacious medical therapies have not been developed for imatinib-resistant DFSP. To this end, we established the first patient-derived models of imatinib-resistant DFSP. Cell lines and mouse xenografts were established from DFSP105, an imatinib-resistant fibrosarcomatous DFSP, and were characterized by SNP arrays and sequencing to identify targetable genomic alterations. Findings were validated in vitro and in vivo, and confirmed in a case series including 12 DFSP and 6 fibrosarcomatous DFSP. SNP analysis of DFSP105 revealed a homozygous deletion encompassing CDKN2A. The resultant p16 loss implicated CDK4/6 as a potential therapeutic target in DFSP. In further studies, we demonstrated CDKN2A homozygous deletion in 1 of 12 conventional DFSP vs. 2 of 6 fibrosarcomatous DFSP. In vitro treatment of DFSP105 with two structurally distinct selective CDK4/6 inhibitors, PD-0332991 and LEE011, led to inhibition of RB1 phosphorylation and proliferation (GI50 160 nM and 276 nM, respectively). In vivo treatment of DFSP105 with PD-0332991 (150 mg/kg) inhibited xenograft growth in mice, in comparison with imatinib-treated or untreated tumors. In conclusion, CDKN2A deletion is a novel mechanism of DFSP genetic progression. CDK4/6 inhibition is a preclinically effective treatment against p16-negative, imatinib-resistant fibrosarcomatous DFSP, and should be evaluated as a therapeutic strategy in patients with imatinib-resistant DFSP. Citation Format: Adrian Marino-Enriquez, Grant Eilers, Jeffrey Czaplinski, Mark Mayeda, Derrick Tao, Meijun Zhu, Jason L. Hornick, Ewa Sicinska, Andrew J. Wagner, Jonathan A. Fletcher. Genomic analyses and novel models validate CDK4 as a therapeutic target in imatinib-resistant dermatofibrosarcoma protuberans. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 607. doi:10.1158/1538-7445.AM2015-607

10553 Background: We report on IM activity in patients (pts) with metastatic DFSP/FS-DFSP and on the gene expression profile (GEP) analysis of pure DFSP versus FS-DFSP, aimed at identifying prognos...

Background Dermatofibrosarcoma protuberans (DFSP) is a rare malignant tumour of the skin, with an estimated incidence of 0.8 to five cases per 1 million people per year. Objective To study epidemiological, immunohistochemical and clinical features, delay in diagnosis, type of treatment and outcome of DFSP from 1982 to 2002. Methods Using data from the population-based cancer registry, 66 patients with pathologically proved DFSP were included (fibrosarcomatous DFSP were excluded). Each patient lived in one of the four departments of Franche-Comte (overall population of 1 million people) at the time of diagnosis. The main data sources came from public and private pathology laboratories and medical records. The rules of the International Agency for Research on Cancer were applied. Results The estimated incidence of DFSP in Franche-Comte was about three new cases per 1 million people per year. Male patients were affected 1.2 times as often as female patients were. The trunk (45%) followed by the proximal extremities (38%) were the most frequent locations. DFSP occurred mainly in young adults between 20 and 39 years of age. Mean age at diagnosis was 43 years, and the mean delay in diagnosis was 10.08 years. Our 66 patients initially underwent a radical local excision. Among them, 27% experienced one or more local recurrences during 9.6 years of follow-up. There was one regional lymph node recurrence without visceral metastases. These recurrences were significantly related to the initial peripheral resection margins. We observed a local recurrence rate of 47% for margins less than 3 cm, vs. only 7% for margins ranging from 3 to 5 cm [P = 0.004; OR = 0.229 (95%, CI = 0.103–0.510)]. The mean time to a first local recurrence was 2.65 years. Nevertheless, there was no death due to the DFSP course at the end of the follow-up, and the final outcome was favourable. Conclusion Our study emphasizes the importance of wide local excision with margins of at least 3 cm in order to prevent local recurrence. However, the recent development of inhibitors of signal transduction by the PDGFB pathway should soon modify the surgical strategy, which is often too mutilating.

Dermatofibrosarcoma protuberans is a superficial low-grade sarcoma that rarely evolves into a high-grade fibrosarcoma. Dermatofibrosarcoma protuberans is genetically characterized by the unbalanced chromosomal t(17;22)(q21;q13), usually in the form of a supernumerary ring chromosome. The product of this chromosomal translocation is the chimeric gene COL1A1-PDGFB (collagen type I alpha I-platelet-derived growth factor beta), which is amplified at low levels in the ring chromosome. The aims of this study were to evaluate (1) whether genomic gains of this fusion gene occur during the clonal evolution of dermatofibrosarcoma protuberans into fibrosarcomatous dermatofibrosarcoma protuberans and (2) whether there is a difference between the number of genomic copies of COL1A1-PDGFB between classic dermatofibrosarcoma protuberans and dermatofibrosarcoma protuberans areas associated with fibrosarcomatous dermatofibrosarcoma protuberans. Eleven cases of fibrosarcomatous dermatofibrosarcoma protuberans with both dermatofibrosarcoma protuberans and fibrosarcomatous areas and 10 cases of classic dermatofibrosarcoma protuberans were studied. Genomic copies of COL1A1-PDGFB were evaluated by fluorescence in situ hybridization using a custom designed probe for the PDGFB locus on 4 mum thick paraffin-embedded tissue sections. Genomic gains of the COL1A1-PDGFB gene were observed in six (of 10) fibrosarcomatous dermatofibrosarcoma protuberans in the fibrosarcomatous areas when compared to the dermatofibrosarcoma protuberans areas of the same tumor (2-7 gene copies (median PDGFB copy gain, 2.8) versus 1-3 gene copies (median PDGFB copy gain, 1.7), respectively, P=0.004). Four fibrosarcomatous dermatofibrosarcoma protuberans did not show genomic gains of COL1A1-PDGFB fusion gene between the two areas. Essentially no difference in the copy number of COL1A1-PDGFB fusion gene was observed between dermatofibrosarcoma protuberans areas of classic dermatofibrosarcoma protuberans and dermatofibrosarcoma protuberans areas of fibrosarcomatous dermatofibrosarcoma protuberans (median PDGFB copy gain of 1.8 versus 1.7, respectively, P=0.36). Genomic gains of COL1A1-PDGFB fusion gene is possibly an oncogenic mechanism that is identified in the clonal evolution of a subset of dermatofibrosarcoma protuberans that evolves into fibrosarcomatous dermatofibrosarcoma protuberans. Since this finding was not observed in all cases of fibrosarcomatous dermatofibrosarcoma protuberans, other oncogenic mechanisms may be operating in this form of tumor progression. Copy number of COL1A1-PDGFB fusion gene in the classic dermatofibrosarcoma protuberans areas does not seem to be a major predisposing mechanism for fibrosarcomatous transformation.

Dermatofibrosarcoma protuberans (DFSP) is a superficial tumor characterized by high rates of local recurrence and a small risk of metastasis. Fibrosarcomatous (FS) areas rarely arise in DFSP, and considerable controversy exists as to whether these tumors have a higher risk of metastasis than the typical DFSP. The aim of this study was to reappraise the prognostic significance of FS changes in DFSP by analyzing 41 patients from the consultation files of our institution. The study included 23 females and 18 males, with a median age of 48 years (range, 16-100 years). Eighteen lesions were located on the trunk, 16 on the extremities, and 7 on the head/neck region. All tumors were treated with local excision, and the surgical margins were considered positive for tumor in 22 of 39 cases (56%). Fibrosarcomas arose de novo in 38 cases and as a recurrence in 3 cases. All tumors involved the dermis and subcutis, and the FS component comprised 5% to 95% of the tumor area (median, 60%). Mitotic rates of the FS component (median, 20 mitoses/10 high-power fields [HPFs]; range, 5-48/10 HPFs) were considerably higher than those of the neighboring DFSP component (0-2 mitoses/10 HPFs). Immunohistochemical analyses showed that CD34 expression was stronger and more extensive in the DFSP component (97% positive; median intensity, 3+) than in the FS component (81% positive; median intensity, 2+). The MIB-1 labeling index was higher in the FS areas (median, 20%; range, 5%-45%) than in the DFSP areas (3%). Expression of p53 was present in 92% of the FS areas and in only 3% of adjacent DFSP areas. Follow-up data revealed that 8 patients had local recurrences, 4 patients (10%) had metastases, and 2 patients died of disease. None of the variables evaluated, including margin status, FS proportion, and mitotic count, correlated with disease progression. We demonstrate that FS change in DFSP is a form of tumor progression that carries an increased risk of metastasis over classic DFSP and is associated with gains of p53 mutations and increased proliferative activity.

A rare case of dermatofibrosarcoma protuberans, which contained low-grade fibrosarcoma with giant rosettes in its recurrence areas is described. The giant rosettes lying in the fibrosarcomatous area produced a pattern similar to that of so-called hyalinizing spindle cell tumor with giant rosettes. The transitions between the tumor components were gradual, and both primary and recurrent lesions showed diffuse immunoreactivity for CD34. The presence of giant rosettes in fibrosarcomatous areas of dermatofibrosarcoma protuberans suggests a possible histogenetic relationship between fibrosarcomatous areas of DFSP and hyalinizing spindle cell tumor with giant rosettes.