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A 3-year-old neutered male Labrador Retriever was referred for investigation of a painless, palpable swelling on the right shoulder. Computed tomography identified a well-defined mass with attenuation characteristics of fat, soft tissue, and mineralization. A surgical excision followed by histopathology confirmed an ossifying chondrolipoma. Postoperative follow-up showed no complications or recurrence at the 6-month recheck. Ossifying chondrolipoma should be considered in the differential diagnosis of soft tissue neoplasms., (© 2025 American College of Veterinary Radiology.)

Rationale: Cardiac lipomas are known to cause functional disturbances and symptoms by compressing adjacent tissues or organs, leading to potential complications such as dyspnea, palpitations, and cardiac arrhythmias. We report a case of a 52-year-old female with a large, well-circumscribed lipoma in the right atrium. This rare condition required a comprehensive diagnostic approach and therapeutic strategy for effective management., Patient Concerns: A 52-year-old female patient presented to the hospital with complaints of palpitations and fatigue lasting for 1 month, accompanied by the recent discovery of a cardiac mass via echocardiography over the past 2 days. In addition, she reported occasional episodes of a dry cough., Diagnoses: Both echocardiography and cardiac computed tomography imaging revealed an isoechoic mass within the right atrium, characterized by a regular shape and close attachment to the right atrial wall, displaying noticeable mobility. Histopathological analysis following surgical intervention confirmed that the tumor was predominantly comprised of adipocytes., Interventions: The patient underwent successful resection of the right atrial lipoma, followed by reconstruction of right atrium using a bovine pericardial patch under extracorporeal circulation with a beating heart., Outcomes: Postoperative recovery was complete, with resolution of symptoms including palpitations and fatigue. A follow-up echocardiogram on the 66th day postsurgery confirmed the absence of any residual tumor., Lessons: Patients with small lipoma often remain asymptomatic. However, large or rapidly progressing tumors may elicit symptoms such as chest pain, dyspnea, and palpitations. For asymptomatic patients with small tumors, regular observation and follow-up are typically advised to monitor tumor growth and the emergence of symptoms. Conversely, patients with large tumors or overt symptoms should be recommended for prompt surgical intervention. In this case, preoperative anatomical evaluation for the lipoma involves the right atrial free wall, which is crucial to prevent excessive resection, damage to the lateral bundle branch, and subsequent postoperative cardiac dysfunction or arrhythmia, as exemplified in this patient., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2025 the Author(s). Published by Wolters Kluwer Health, Inc.)

Fibrolipoma is defined as a typical lipoma transected by variable amounts of paucicellular and collagenous fibrous components. Oral and lingual fibrolipomas are well-recognized histological entities in human medicine that are slightly more prevalent in females, occur most commonly after the fourth decade, and arise from the buccal mucosa. The documentation of this neoplasm in the oral cavity is lacking in veterinary medicine. Through a multi-institutional retrospective compilation of cases submitted to diagnostic pathology services, here we describe the clinical and pathologic features of oral fibrolipomas in dogs. A total of 112 cases of oral fibrolipomas in dogs were retrieved. The mean age was 10.1 years (range 2-16 years, ±2.63 years standard deviation), with an average tumor size of 1.7 cm (range 0.2-8 cm, ±1.1 cm standard deviation). The most common location was the tongue (57.1%, 64/112), followed by the buccal mucosa (15.2%, 16/112), sublingual area (8.0%, 9/112), gingiva and lip (4.5%, 5/112 each), and palate (1 case). The anatomical location of oral fibrolipomas only differed significantly among the dog breeds ( P < .001) but not among sex, age, anamnesis, or reason for submission. The tumor was most commonly reported in males (69.7%, 78/112), and in 62.5% (70/112) of the cases, the tumor was an incidental finding. Fibrolipoma should be considered a differential diagnosis when considering benign lingual and other oral soft tissue masses in dogs., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Cynthia Bell is the owner of Specialty Oral Pathology for Animals, Alexis Berrocal is the owner of Histopatovet, and Tatiane Terumi Negrão Watanabe is employed at Antech Diagnostics, Mars Petcare Science & Diagnostics. The remaining authors declared no potential conflicts of interest concerning the research, authorship, and/or publication of this article.

Lipomas are benign soft tissue tumors composed of mature adipocytes, commonly found in subcutaneous tissues. Despite their prevalence in various body regions, they are relatively rare in the oral and maxillofacial regions. This study retrospectively analyzed the clinical and imaging characteristics, as well as the treatment outcomes of 57 patients diagnosed with lipoma. Among these, 42 cases (73.7%) were located in the oral-maxillofacial and head-neck regions, predominantly in areas with relatively abundant adipose tissue, including the facial/cheek area, parotid region, submental/submandibular area, and neck. In addition, this study presents a rare case of tongue lipoma in a 57-year-old male, highlighting the clinical features, diagnostic challenges, and treatment approach. The patient presented with a painless mass on the left side of the tongue that had gradually increased in size over 5 months. Physical examination revealed a firm, well-defined, moderately mobile mass measuring ~3.0×1.5 m. Imaging, including enhanced magnetic resonance imaging, suggested a diagnosis of lipoma, leading to surgical excision. The excised mass was yellowish, encapsulated, and soft. Intraoperative frozen section biopsy confirmed it as a fat-derived tumor consistent with a lipoma, and postoperative pathological examination further identified it as a spindle cell/pleomorphic lipoma. The patient experienced a smooth recovery without complications, with normal tongue function restored. This case underscores the significance of including lipoma in the differential diagnosis of tongue masses and demonstrates the efficacy of surgical excision in managing such rare tumor., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

We report the noninvasive imaging diagnosis of a massive right atrial lipoma in a young male patient. Echocardiography and myocardial contrast echocardiography were used to assess echo intensity, tumor size, anatomic boundary, hemodynamics, and contrast agent perfusion. Dual-source CT revealed that the CT value of the tumor was fat density. Cardiac MRI showed high signals of T1 and T2 weighted images, while the low signals of fat saturation sequences. Finally, the tumor was surgically resected and the diagnosis of right atrial lipoma was confirmed by pathological section. Our study indicates that multimodal imaging may facilitate a potential pathological diagnosis before biopsy and can help plan further treatment., Competing Interests: Declarations. Ethics approval and consent to participate: The patient provided written informed permission, and ethical approval was waived. All methods were performed in accordance with the Declaration of Helsinki. Consent for publication: Written informed consent was obtained from the patient for the publication of this case report and any accompanying images. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Lipomas are the most common soft tissue tumours in adults, but they represent less than 10% of paediatric mesenchymal tumours. In adults, they are typically slow growing and painless. We describe an adolescent with a rapidly enlarging neck mass causing dyspnoea and chest pain. Physical examination revealed a soft mobile mass extending from the angle of the mandible to the clavicle, with imaging demonstrating a 3×6×15 cm lipoma extending to the superior mediastinum with mass effect on key neck and mediastinal structures. It was surgically resected without complications and all presenting symptoms resolved. Along with the two other reported cases of giant lipomas of the neck in children, this presentation illustrates the rapid growth and symptomatic nature of giant lipomas in children. Surgical excision is the recommended treatment., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Rationale: Lipoma arborescens (LA) is a rare, benign proliferative disorder of the synovial lining that typically affects middle-aged individuals, predominantly in the knee joint. However, its occurrence in younger patients is unusual and may pose unique diagnostic and therapeutic challenges. This case report aims to highlight the clinical, imaging, and therapeutic aspects of LA in a young adult, thereby expanding the understanding of its presentation in this age group., Patient Concerns: A 22-year-old male presented with acute swelling and pain in the right knee following a minor sprain. Although the symptoms persisted and worsened over several days, the patient was particularly concerned about his prognosis and the possibility of recurrence. Given the rarity of LA, he expressed anxiety about being diagnosed with such an uncommon condition at his age and feared the potential impact on his future mobility. He was also apprehensive about the risks of surgery and questioned why he, at such a young age, was affected by this rare condition., Diagnoses: Initial clinical assessment was inconclusive, leading to further investigations. Magnetic resonance imaging findings suggested a meniscal tear and the presence of LA, characterized by fat globules and joint effusion, which was confirmed during arthroscopic surgery., Interventions: The patient underwent arthroscopic surgery involving trimming of the medial meniscus and debridement of the synovium. Surgical findings included extensive synovial proliferation and intra-articular fat globules, which were histologically confirmed as LA., Outcomes: Postoperative recovery was successful, with significant improvement in joint function and alleviation of symptoms. Follow-up magnetic resonance imaging confirmed the absence of abnormal synovial proliferation., Lessons: This case report underscores the diagnostic and therapeutic challenges associated with LA in a young patient, highlighting the importance of considering LA in differential diagnoses of acute knee swelling, especially when initial evaluations are inconclusive. Through a combination of imaging, arthroscopic intervention, and histopathological confirmation, this case illustrates an effective approach for accurately diagnosing and managing LA. By documenting this atypical presentation in a young adult, this report contributes to the limited literature on LA in younger populations, aiming to enhance clinical awareness and guide future cases involving similar joint lesions., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

The entity commonly referred to as chondrolipoma is a rare and enigmatic breast lesion with unclear histogenesis and a complete lack of molecular characterization. It is uncertain whether it represents a hamartoma, choristoma, or a distinct neoplasm, including possibly a variant of mammary-type myofibroblastoma. We report two additional chondrolipomatous lesions of the breast. The lesions had varying histologic and immunohistochemical features similar to myofibroblastoma, including the loss of retinoblastoma (Rb) protein expression in one lesion. Molecular analysis by chromosomal microarray analysis performed on a second lesion did not demonstrate a loss of 13q14 or 16q typical of myofibroblastoma. Our findings further support the concept that at least a subset of breast lesions that historically have been classified as chondrolipoma are related to myofibroblastoma. However, the lack of myofibroblastoma-specific molecular alterations in one lesion suggests chondrolipomas may also have varying origins., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Hibernoma is a relatively uncommon benign neoplasm of brown adipose tissue which usually affects head and neck region, thigh and rarely breast. There are different subtypes of hibernoma with the spindle cell-type is the least common one. Herein, we are reporting a case of this rare spindle cell hibernoma in a location which has not been previously reported: perinephric adipose tissue. This tumor was presented as a renal mass on imaging.

Background: Lipomatous tumors represent the most common type of soft tissue neoplasms. Mouse double minute 2 homolog (MDM2)/cyclin-dependent kinase 4 (CDK4) immunostaining is considered effective in differentiating between benign lipomas and intermediate malignant atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLPSs). However, these tumors have traditionally been diagnosed histopathologically using hematoxylin and eosin-stained specimens, which is referred to here as morphological diagnosis. In this study, the accuracy of morphological diagnoses that had been made before MDM2/CDK4 immunostaining became available for distinguishing between lipoma and ALT/WDLPS was examined., Methods: The study participants were 109 patients with a morphological diagnosis of lipoma (68 patients) or ALT/WDLPS (41 patients) who had undergone surgical resection of the tumor in our hospital between 2009 and 2012. Tissue samples from all patients were used for MDM2/CDK4 immunostaining and the confirmation of MDM2/CDK4 amplification by fluorescence in situ hybridization (FISH)., Results: Of the 41 patients with a morphological diagnosis of ALT/WDLPS, only 17 were positive for MDM2 FISH. In addition, one of the 68 patients with a morphological diagnosis of lipoma showed MDM2 amplification by FISH. When the definitive diagnosis of ALT/WDLPS was made by the positive results of MDM2 FISH, the sensitivity and specificity of morphological diagnosis were 41.5% and 98.5%, respectively. The sensitivity of MDM2 and CDK4 immunostaining was 55.6% and 40.0%, respectively, and their specificity was 87.0% and 84.6%, respectively. This indicates that the diagnostic accuracy of these immunostaining assays was not particularly high. The clinical features suggesting ALT/WDLPS were: patient age (older), maximum tumor diameter (large, cut-off value of 125 mm), tumor location (lower limb), and tumor depth (deep-seated)., Conclusions: Morphological diagnosis alone can accurately diagnose lipomas. However, it has a propensity to overdiagnose ALT/WDLPS. Thus, MDM2 FISH should be used more proactively, not only for lesions with obvious morphological abnormalities, but also for lipomatous tumors that are clinically suggestive of ALT/WDLPS., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Clinical Research Ethics Committee of Nagasaki University Hospital (Approval Number: 17061909–3). Written informed consent was waived by this committee for this retrospective analysis of routinely acquired imaging and clinical data. The outline of this research was published on the homepage of the Clinical Research Center of Nagasaki University Hospital. This guaranteed the patients and any other individuals the opportunity to refuse participation in the study. We did not receive any refusion of participation. Each author certifies that all investigations were conducted in conformity with the ethical principles of research. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Lipomas of the talus are rare benign bone lesions. They are usually atraumatic in aetiology with a male preponderance and generally occur between the third and sixth decades of life. We report the case of a man in his 30s who had presented with pain and swelling in the posteromedial aspect of his left ankle of 6 months' duration, associated with functional restrictions, and was diagnosed as a case of intraosseous lipoma involving the talus. The patient was managed surgically by extended curettage and iliac crest bone grafting. After a period of 1 year, he was able to perform all activities and no recurrence was observed., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Soft tissue lesions are among the most prevalent forms of tumors or tumor-like alterations within the oral cavity. They exhibit a wide spectrum of characteristics, ranging from benign, noninvasive lesions to malignant tumors, which collectively present a diagnostic challenge. A 67-year-old patient presented with an incidental finding of induration on the right cheek during dental hygiene. The intraoral examination revealed a soft, non-tender swelling measuring 20 mm in diameter. The sensitivity and percussion tests for the teeth in the fourth quadrant yielded unremarkable results. Panoramic radiography (OPG) revealed tip-ping of the premolars and an unclear apical finding in region 44. Cone-beam computed tomography (CBCT) revealed a sharply defined, lobulated hypodense lesion in the right buccal area. To clarify the diagnosis and optimize perioperative management, a 3 Tesla dental magnetic resonance imaging (MRI) scan was performed. This identified a 23×6×23 mm lipoma along the right mandibular ramus, causing detachment of the buccinator and de-pressor anguli oris muscles. A cinematic rendering reconstruction derived from the MRI data facilitated enhanced visualization for preoperative planning. The surgical excision was performed under local anesthesia, resulting in the successful removal of the neoplasm while preserving the mental nerve and submandibular gland. Histo-pathology confirmed the presence of a lobulated mature cell lipoma. The patient exhibited no complications during the removal of the sutures, with complete wound healing and no recurrence observed. This article highlights the efficacy of advanced MRI diagnostics and post-processing techniques in the management of ambiguous soft tissue neoplasms., (Copyright 2024 Adib Al-Haj Husain, Esra Salzer, Bernd Stadlinger. License: This work is licensed under a Creative Commons Attribution 4.0 International License.)

Background: Cardiac lipoma, a seldom-encountered benign tumor positioned beneath the endocardium, has the potential to impair electrophysiological functions. Diagnosis is principally based on imaging modalities. The uniqueness of this case lies in the tumor's extension both internally and externally within the right atrium, rendering it of special interest. From a clinical standpoint, surgical removal is commonly advocated, wherein early intervention is pivotal in improving patients' long-term prognoses., Case Presentation: A 35-year-old male was admitted to the hospital for treatment subsequent to the identification of a cardiac mass two days prior. Initial diagnostic assessments, encompassing CT scans and echocardiography, identified a space-occupying lesion within the heart. The patient underwent surgical excision of the cardiac tumor, utilizing mild hypothermic extracorporeal circulation via femoral vessel access. Intraoperative findings revealed adipose-like tissue of a "dumbbell-shaped" configuration situated both within and external to the right atrium, measuring approximately 8 cm*9 cm internally and 7 cm*6 cm externally, with the extracardiac mass being marginally larger. Postoperative pathological analysis confirmed a cardiac lipoma diagnosis. A follow-up echocardiogram conducted three months post-surgery exhibited no notable abnormalities. The patient is under continuous observation to monitor for any recurrence or potential long-term complications., Conclusion: In this case report, we detail with precision a rare cardiac pathology manifested by an expansive infiltrative lipoma that pervades the endocardial and epicardial layers of the right atrium. After thorough preoperative diagnostic workup and evaluation, we contend that surgical intervention represents the optimal therapeutic approach for managing such conditions, with the goal of preemptively reducing the likelihood of cardiac compression or intracardiac obstruction., (© 2024. The Author(s).)

Lipomas are the most prevalent benign soft-tissue tumours, however, pedunculated fibrolipoma in the buttock is rare. Here, the case of a Chinese male patient in his early 70s with a 50-year history of a growing pedunculated fibrolipoma on his right buttock is presented. The attending physician and the registered nurse collaborated on a treatment plan, leading to a successful resection with rhomboid flap transfer. The operation went smoothly, and with continued home care and follow-ups, the patient recovered well, without complications. At 4 months post-surgery, the incision had healed perfectly, boosting the patient's psychological state and allowing him to resume his daily activities unhindered., Competing Interests: Declaration of conflicting interestThe authors declare that there is no conflict of interest.

We present our single-centre experience of two cases of lipochoristoma, a rare lesion causing unilateral hearing loss. Differential diagnoses include the more common vestibular schwannoma, haemangioma and meningioma. Diagnosis was confirmed with fat suppression sequences on MRI. Management of both patients was with serial imaging, under the guidance of neuro-otology multidisciplinary team, due to the slow and typically non-aggressive progression of this lesion., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Colonic lipomas (CLs) are benign tumors of the adipose tissue of the gastrointestinal tract that are often asymptomatic. A search of medical literature in English using PubMed and Google Scholar was conducted for articles related to CL. Occasionally, patients present with intestinal bleeding or obstructive symptoms. Although intussusception is commonly observed in children, it is rare in adults. Moreover, CL as the most common entity, is very rare, with an incidence rate of 0.035% to 4.4%. Although fatty composition can assist in diagnosis through computed tomography and magnetic resonance imaging, the latter cannot exclude local infiltration. CLs are distributed evenly between both sexes and can be located anywhere in the gastrointestinal tract; however, they are more frequently located in the colon, particularly in the right colon and cecum (39.6%), followed by the transverse colon (25%), descending colon (20.8%), and the sigmoid colon (14.6%). Symptoms included abdominal pain (79.2%), alterations in bowel habits (45.8%), rectal bleeding (22.9%), colocolic intussusception (50%), weight loss (6.2%), vomiting (14.6%), and nausea (12.5%). Surgical and endoscopic techniques are widely used to manage CLs. The challenge for physicians is differentiating this lesion from malignant colonic lesions, at the outset. The risk of misdiagnosis is possible, and the recommendation in cases of doubt is still segmental surgical resection, as it ensures correct collection of lymph nodes for appropriate staging of presumed colonic carcinoma., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

A rare instance of extravascular lipomas located over the subclavian vein in a woman in her early 60s presented unique diagnostic and therapeutic challenges due to their close proximity to critical structures. Lipomas, which are the most commonly occurring benign soft tissue tumours, are typically composed of mature adipocytes. Although lipomas can develop in any region of the body, they are most commonly found in the subcutaneous tissues of the trunk and proximal limbs. Extravascular lipomas, especially those near major blood vessels like the subclavian vein, are extremely uncommon.In this particular case, the tumour was extensively in contact with the right subclavian vein, though there was no intravascular involvement. The lipomatous tumour was successfully excised during surgery, with the subclavian vein and surrounding structures being preserved. Histopathological analysis confirmed the diagnosis of a benign lipoma. This case highlights the significance of early diagnosis, meticulous surgical planning and multidisciplinary collaboration to achieve the best possible outcomes., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Lipomas of the palatine tonsil are rare benign neoplasms in clinical practice. We present a case of palatine tonsillar fibroangiolipoma in a 50-year-old Chinese male with a history of multiple lipomas on the back and extremities. It was diagnosed based on histological examination and integrated analysis. Good wound healing and no evidence of recurrence were noted within 6 months follow-up after tonsillectomy. This article also puts a spotlight on the differential diagnosis of benign tonsillar tumors and reviewed recent relevant literature., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Abstract: Lipomatous hypertrophy of the interatrial septum (LHIS) is a rare but benign cardiac tumor that can be found on cardiac imaging such as echocardiogram, or during surgery or an autopsy. Cardiac MRI is the best imaging modality to determine the borders of the tumor and its extension into the intraventricular septum and ventricular free wall. Patients require close monitoring because LHIS may cause right or left outflow tract obstruction or superior vena cava obstruction, requiring cardiac surgical intervention. This article describes a patient with LHIS who underwent cardiac surgery because of her increasing symptomatology., (Copyright © 2024 American Academy of Physician Associates.)

Spindle cell lipoma is a very rare occurrence in the larynx and can be cured by complete excision. In this case report we present the case of a 71-year-old female who presented to the otorhinolaryngology outpatient department of Northwest General Hospital and Research Centre, Peshawar, with complaints of occasional irritation and a foreign body sensation in the throat while swallowing, for the last three years. She had undergone a surgical procedure 30 years back for the same complaint and remained asymptomatic till three years back. On examination, through fibre-optic laryngoscope, the attending surgeon saw an abnormal mass arising from the aryepiglottic folds of the larynx. An excisional biopsy was performed through micro-laryngoscopy. The patient's symptoms subsequently improved and she is currently doing well. Histopathological reports confirmed it as spindle cell lipoma.

Intussusception is rare in adults, making it a challenging and often delayed diagnosis. Patients may re-present with non-specific and subacute abdominal symptoms. Abdominal CT is the most sensitive imaging modality and is often required to make the diagnosis of intussusception. In contrast to the paediatric population, intussusception in adults is most often associated with a pathological lesion acting as a lead point. In adults, the lead point is often secondary to malignancy, though benign lesions can also be implicated. As such, surgical management with selective resection is the mainstay of treatment in adults. We describe a rare case of ileocaecal intussusception in an adult secondary to a large ileocaecal lipoma, successfully treated with laparotomy and resection in a remote Western Australian hospital. The increasing availability of CT imaging and skilled general surgeons in rural and remote Australia allows for the diagnosis and surgical management of such cases without inter-hospital transfer., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Pseudoangiomatous spindle cell lipoma is a rare pattern within the spindle cell lipoma spectrum that exhibits a remarkable histological pattern characterized by its resemblance to vascular lesions, creating a pseudoangiomatous appearance. Approximately 20 to 30 reports have been described in the literature. In this context, we present an intriguing report of pseudoangiomatous spindle cell lipoma showcasing a unique low-fat pseudo angiomatous pattern in a 61-year-old male patient presented with a 6-cm subcutaneous mass on his right arm, which was thoroughly investigated and subsequently excised. Microscopic examination revealed bland spindle cells infiltrates within a fibromyxoid stroma. Notably, the tumor exhibited distinctive branching and dilated vascular-like spaces that formed pseudopapillary (villiform) projections. Interestingly, the tumor displayed certain regions featuring mature adipose tissue components, alongside hyalinized blood vessels. No necrosis, atypical spindle cells, increased mitotic activity, or pleomorphic lipoblasts were observed. The immunohistochemical evaluation demonstrated diffuse positive staining for CD34 and negative staining for STAT6. This report of a low-fat pattern of pseudoangiomatous spindle cell lipoma underscores the importance of recognizing and characterizing rare entity subtype for accurate diagnosis and appropriate management. This report contributes to the expanding understanding of the diverse presentations of pseudo angiomatous spindle cell lipomas and underscores the significance of comprehensive histopathological assessment., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Documentation of lingual tumors is scarce in nonhuman primates., Methods: Through a multi-institutional retrospective study we compile cases of primary and metastatic neoplasia in non-human primates., Results: We describe five cases of lingual neoplasia. Three cases are primary lingual tumors: chondro-osteoblastic lipoma in a howler monkey, squamous cell carcinoma, and fibroma in two baboons. We describe two cases of metastatic lymphoma in the tongue in rhesus macaques. A literature review of published lingual neoplasia in nonhuman primates is included in this manuscript., Conclusion: Lingual neoplasia is seldom reported in non-human primates., (© 2024 The Author(s). Journal of Medical Primatology published by John Wiley & Sons Ltd.)

Background: Fibrolipoma of the lower lip is an uncommon condition with limited documentation in the literature. This paper provides updated insights into oral and maxillofacial lipomas through a detailed case report and comprehensive literature review, discussing clinical features, pathogenesis, diagnostic approaches, histopathology, and therapeutic strategies., Case Presentation: A 54-year-old female presented with a painless, enlarging mass on the inner aspect of her right lower lip, first noticed 2 years prior. The mass, now the size of a peanut, interfered with her eating and speech. Physical examination revealed a 2.0 × 2.5 × 1.0 cm mass beneath the mucous membrane of the right lower lip. It was firm, well-demarcated, and mobile. Surgical excision was performed, and histopathological analysis confirmed the diagnosis of a lower lip fibrolipoma. The lesion was successfully removed without recurrence., Conclusion: Lipomas in the oral and maxillofacial regions are rare, slow-growing benign tumors, particularly within the lips. Although their diagnosis is straightforward based on clinical presentation, histopathological confirmation is essential. Surgical resection remains the treatment of choice, with excellent prognostic outcomes., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Intraneural lipomas and lipofibromas (also called lipofibromatous hamartomas) are rare, benign tumours occurring in peripheral nerves in the forearm and wrist. They usually present as asymptomatic masses, but if they are large enough, they may cause symptoms of compression neuropathy. Intraneural lipomas and lipofibromas differ with regard to anatomy and clinical behaviour: the former tumour has a well-defined capsule and most commonly occurs within the median nerve in the forearm and wrist. It is diagnosed in the fourth and fifth decades of life and seen more frequently in women. The latter (lipofibroma) has no capsule, is infiltrative in nature, is composed of fatty and fibrous tissue and also most commonly seen in the median nerve. It occurs in a younger age group with no sexual predominance. Due to these differences, these lesions are managed differently 1 2., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Parosteal lipomas and osteochondromas of the head and neck are uncommon benign tumors, constituting a small fraction of lipoma and bone tumor cases. We present a unique case of a 66-year-old male with a parosteal lipoma overlying an osteochondroma in the anterior midline neck, causing dysphagia. Surgical excision confirmed the diagnosis, and a literature review revealed similar cases predominantly adjacent to the mandible or calvaria. This case emphasizes the need to have parosteal lipoma and osteochondroma on the differential diagnosis for patients presenting with a firm mass of the central neck, especially with a history of trauma. Laryngoscope, 134:2844-2847, 2024., (© 2023 The American Laryngological, Rhinological and Otological Society, Inc.)

We describe the presentation and treatment of the first reported case of a nasopharyngeal pleomorphic lipoma. The mass was successfully treated with a combined endoscopic trans-oral surgical excision approach by using low temperature-controlled plasma technology, resulting in optimal patient outcomes. Laryngoscope, 134:2710-2712, 2024., (© 2023 The American Laryngological, Rhinological and Otological Society, Inc.)

Tumours of adipose tissue origin are relatively rare in the head and neck. Here, we report a case of an unfamiliar lipomatous lesion that involved the neck and mediastinum. A nil-comorbid man in his 40s presented with a slowly progressive anterior neck swelling of 3 years, which was diagnosed as lipoma by histopathological sampling. Computed tomography demonstrated the lesion to be involving parapharyngeal and retropharyngeal spaces with mediastinal extension. The lesion was removed by the transcervical approach. The final histology of the excised specimen, with immunohistochemistry for mouse double minute 2 (MDM2) and p16, suggested an atypical lipomatous tumour (ALT). This report accentuates the occurrence of this rare neoplasm in the neck, which often mimics lipoma clinically. Although radiology can demonstrate suggestive features, histology with MDM2 and/or p16 positivity can confirm the diagnosis of ALT as against the lipoma. A successful transcervical excision, despite the deeper extension of the lesion between the critical structures of the neck and mediastinum, demonstrates the non-infiltrating nature of the tumour., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

This retrospective study aims to examine the characteristics and treatment approaches of colon lipomas, which are benign tumors found in the colon. We analyzed a cohort of 25 patients, focusing on demographic characteristics, clinical presentation, location and size of the lipoma, concomitant pathologies, and treatment methods. The average age of the patients was 67.3 years, with 36% being male and 64% female. The majority of lipomas were located in the ascending colon (52%), and their median size was 2 cm. The predominant presenting symptom was constipation, affecting 83.3% of the symptomatic patients. Surgical resection was undertaken in only 1 patient due to obstruction. Statistically significant differences were observed between symptomatic and asymptomatic patients regarding various parameters, including the size of the lipoma (P = .033). Colon lipomas are generally benign and frequently asymptomatic but may necessitate different treatment approaches depending on their size, location, and the presence of symptoms. Further studies are imperative to refine treatment strategies and enhance patient care outcomes., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

We herein report a 27-year-old woman who presented with recurrent knee pain. Laboratory findings revealed minimal inflammation. Arthrography revealed structures resembling adipose tissues. Magnetic resonance imaging showed a high signal intensity of these structures, leading to the diagnosis of lipoma arborescens (LA). Synovectomy was performed. Pathology revealed adipocyte proliferation and B-cell clusters but no T-cell infiltration. A serum cytokine analysis revealed low levels of interleukin-6 and tumor necrosis factor-α compared with patients with rheumatoid arthritis. The pathogenesis of LA remains unclear, but immunostaining and serum cytokine levels may provide valuable data for future investigations.

Introduction: Gastrointestinal (GI) lipomas are rare; however, they are frequent enough to be considered in the differential diagnosis of gut tumours. Here, we present our experience with GI lipomas managed at our institute over the last three years., Methods: This is a retrospective cohort study of patients with GI lipomas managed between January, 2020 and April, 2023 at a tertiary care centre. Clinical presentation, location, and details of surgical procedure were analysed., Results: Ten patients were included, six of whom had lipoma in the colon, one in the stomach, and one each in the duodenum, jejunum, and ileum. The mean age at the time of presentation was 48.8 years (range, 19-77 years), and strong male preponderance (4:1) was noted. Preoperative diagnosis of lipoma on cross-sectional imaging was possible in all patients. All patients were symptomatic and were managed surgically., Conclusions: While GI lipomas are generally considered to be indolent and benign tumours, they can potentially lead to severe complications. The utilisation of computed tomography and magnetic resonance imaging has brought about a significant transformation in diagnosing this condition, enabling preoperative identification in most cases. The surgery offers a definitive treatment with minimal risk of postoperative complications.

The classification and work-up of adipocytic neoplasms remains challenging and sometimes controversial. Since its initial description by Dr. Enterline, the variety of subtypes and morphological appearances considered to represent the spectrum of atypical lipomatous tumor/well differentiated liposarcoma (ALT/WDL) has expanded, resulting in significant morphologic overlap with other entities, including the recently described atypical spindle cell/pleomorphic lipomatous tumor (ASPLT), conventional spindle cell/pleomorphic lipoma (SPL), and so-called "low-grade" forms of dedifferentiated liposarcoma (DL). Nevertheless, the distinction of most examples of ALT/WDL from lipomas/lipoma-like lesions is easily performed on routine histologic examination but can be problematic if the characteristic atypical cells are poorly represented, particularly in small biopsy specimens, obscured by other cellular elements (inflammation), or simply not recognized. The discovery that lipomatous tumors harbor specific and unique karyotypes and molecular events has resulted in ancillary tests that can help provide more accurate diagnoses, especially in less-than-optimal scenarios. Confirmation of MDM2 immunohistochemical over-expression and detection of the MDM2 gene rearrangement via fluorescent in situ hybridization (FISH) have proven particularly reliable and useful. While FISH analysis for MDM2 gene amplification may be helpful for confirming (or excluding) ALT/WDL, it also can lead to overutilization and overdependence. Furthermore, a small subset of otherwise typical ALT/WDL lack MDM2 gene amplification, employing alternative molecular pathways. The recent recognition of ASPLT has introduced a tumor easily mistaken morphologically for ALT/WDL, often exhibiting bizarre and pleomorphic lipoblasts, but lacking the underlying molecular abnormalities and subsequent risk of dedifferentiation. ASPLT also have overlapping features with the better-established SPL but with a greater tendency to locally recur and more frequent involvement of the distal extremities. The precise criteria separating cellular forms of ALT from what some consider "low grade" forms of DL remains controversial and inconsistently applied, even among individual pathologists within institutions. Given their underlying shared cytogenetic abnormality, molecular testing has no utility in this distinction. Herein is a comprehensive historical overview of ALT/WDL, with updates on its distinction from other similar lipomatous tumors and DL, including practical evidence-based criteria for the appropriate cost-effective use of MDM2 testing., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Abstract: Intraosseous lipoma of calcaneum is a rare cause of heel pain. Calcaneum is a typical site of involvement of IOL. There are only a few published articles regarding calcaneal intraosseous lipoma and one has been reported from Nepal. We report a case of 35 years female who presented with left heel pain for 1 year. The pain was gradually increasing in intensity and was severe enough to refrain her from activities of daily living. She was surgically operated with curettage and filling the defect with bone cement. There is no residual pain at 2.5 years follow up. We briefly review the postulated pathogenesis, clinical manifestations, diagnosis and various modalities of treatment of intraosseous lipoma. An orthopedic surgeon should have high degree of suspicion regarding the uncommon cause of heel pain and its possible management. When conservative methods do not relieve symptoms, surgical excision and filling the defect with bone cement provides long term relief.

A 14-year-old intact male Chihuahua dog was presented with masses located between the biceps femoris and adductor muscles in both hind limbs. Based on histopathological, immunohistochemical, and ultrastructural findings, we diagnosed these masses as bilateral hibernomas in the femoral regions. The dog had no evidence of recurrence or metastasis of the hibernomas through a 4-month postoperative follow-up. This is apparently the first report of bilateral hibernomas in the femoral regions of a dog. Key clinical message: Bilateral hibernomas should be considered as a differential diagnosis for masses occurring in the femoral regions of dogs., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Spindle cell lipoma (SCL) is a rare form of lipoma, typically occurring as a mass in the back, shoulder or posterior neck of adult males. Most cases present little diagnostic difficulty on fine needle aspiration (FNA), but can be problematic when the SCL is in an unusual location. The authors report a case in the parotid gland in a 75-year-old man. FNA was paucicellular and showed loose collections of spindle cells with mild to moderate atypia, admixed with ropy collagen fibers on a myxoid background. The nuclei showed occasional angulation, interpreted on FNA as suspicious for myoepithelial tumor or low-grade sarcoma. The subsequent excisional specimen was diagnosed as SCL. On retrospective review of the FNA, an additional finding was recognized: 'naked' nuclei with intranuclear lipid vacuoles and positive immunostaining for S100 protein, consistent with Lochkern cells of mature adipocytes. This case highlights the challenges of diagnosing SCL on cytology when no fat-containing cells are apparent on the smear, and stresses the significance of Lochkern cells as a clue for diagnosis., (© 2024 Wiley Periodicals LLC.)

Spindle cell lipomas are a rare type of lipoma usually presenting in middle-aged to older men, often located on the posterior neck or shoulder; presentation on the foot is exceptionally uncommon. We report a 24-year-old man with spindle cell lipomas on the hallux of his left foot. He experienced an uneventful recovery after excision of the mass. We discuss clinical, radiologic, and histopathologic features of spindle cell lipomas and we review the differential diagnosis at this anatomic site.

Atypical spindle cell/pleomorphic lipomatous tumor (ASCPLT) is a rare soft tissue neoplasm, commonly arising in the subcutis (more common than deep soft tissue) of limbs and limb girdles during mid-adulthood. ASCPLT is histologically a lipogenic neoplasm with ill-defined margins composed of a variable amount of spindle to pleomorphic/multinucleated cells within a fibromyxoid stroma. ASCPLTs lack MDM2 amplification, but a large subset show RB1 deletion and variable expression of CD34. Though initially thought to be the malignant form of spindle cell lipoma, ASCPLTs are benign with local recurrences (∼10-15%) and no well-documented dedifferentiation or metastasis., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Several high-grade pleomorphic sarcoma cases that cannot be classified into any existing established categories have been reported. These cases were provisionally classified into undifferentiated pleomorphic sarcoma (UPS). Some dedifferentiated liposarcoma (DDLS) cases may also have been classified into the UPS category due to the absence of MDM2 amplification or an atypical lipomatous tumor/well-differentiated liposarcoma component. We retrieved and reviewed 77 high-grade pleomorphic sarcoma cases, initially diagnosed as UPS in 66 cases and DDLS in 11 cases. Fluorescence in situ hybridization (FISH) analyses of DDIT3 and MDM2 were performed for available cases. Of the cases successfully subjected to DDIT3 FISH (n = 56), nine (7 UPS and 2 DDLS) showed DDIT3 amplification but no MDM2 amplification. Two UPS cases showed both telomeric (5') and centromeric (3') amplification of DDIT3 or low polysomy of chromosome 12, whereas 5 UPS and 2 DDLS cases showed 5'-predominant DDIT3 amplification. Histopathologically, all cases showed UPS-like proliferation of atypical pleomorphic tumor cells. Immunohistochemically, only one case showed focal nuclear positivity for DDIT3, supporting the previous finding that DDIT3 expression was not correlated with DDIT3 amplification. All three cases with focal MDM2 expression involved 5'-predominant amplification, two of which showed DDLS-like histological features. The majority of cases (7/9) showed decreased expression in p53 staining, suggesting that DDIT3 amplification regulates the expression of TP53 like MDM2. From a clinicopathological perspective, we hypothesize that DDIT3-amplified sarcoma, especially with 5'-predominant amplification, can be reclassified out of the UPS category., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Fat-forming solitary fibrous tumor is a rare and specific subtype of solitary fibrous tumor. In this case, a mass of 8.3 cm in diameter was found in a 59-year-old male patient's right retroperitoneum, as revealed by abdominal contrast-enhanced computed tomography (CT) images. The tumor exhibited a well-circumscribed nature and histological features characterized by a combination of hemangiopericytomatous vasculature and mature adipose tissue, comprising around 70% of the total tumor composition. Immunohistochemistry staining revealed diffuse positive expression of STAT6 and CD34 in the tumor cells. Based on these findings, the final diagnosis was determined to be a fat-forming solitary fibrous tumor located in the retroperitoneum. It is important to consider other potential differential diagnoses, including angiomyolipoma, dedifferentiated liposarcoma, spindle cell lipoma, and atypical lipomatous tumor/well-differentiated liposarcoma., (© 2024. The Author(s).)