Objective: To investigate the clinicopathological characteristics, immunophenotype, molecular genetics and differential diagnoses of fibrocartilaginous lipomas which consist of adipose tissue, fibrocartilage and fibrous elements. Methods: The clinicopathological features, immunohistochemical profiles and molecular profiles in six cases of fibrocartilaginous lipomas diagnosed at Foshan Traditional Chinese Medicine Hospital, Fudan University Shanghai Cancer Center, the Fifth Affiliated Hospital of Zhengzhou University and the Fourth Affiliated Hospital of Harbin Medical University from January 2017 to February 2022 were included. The follow-up information, diagnosis and differential diagnoses were evaluated. Results: There were three males and three females with a median age of 53 years (range 36-69 years) at presentation. Tumors were located in the extremities, the head and neck region and trunk; and presented as painless masses that were located in the subcutaneous tissue or deep soft tissue. Grossly, three cases were well defined with thin capsule, one case was well circumscribed without capsule, two cases were surrounded by some skeletal muscle. The tumors were composed of fatty tissue with intermingled gray-white area. The tumors ranged from 1.50-5.50 cm (mean 2.92 cm). Microscopically, the hallmark of these lesions was the complex admixture of mature adipocytes, fibrocartilage and fibrous element in varying proportions; the fibrocartilage arranged in a nodular, sheet pattern with some adipocytes inside. Tumor cells had a bland appearance without mitotic activity. Immunohistochemical analysis using antibodies to SMA, desmin, S-100, SOX9, HMGA2, RB1, CD34, adipopholin was performed in six cases; the fibrocartilage was positive for S-100 and SOX9, adipocytes were positive for S-100, adipopholin and HMGA2; CD34 was expressed in the fibroblastic cells, while desmin and SMA were negative. Loss of nuclear RB1 expression was not observed. Other genetic abnormalities had not been found yet in four cases. Follow-up information was available in six cases; there was no recurrence in five, and one patient only underwent biopsy of the mass. Conclusions: Fibrocartilaginous lipoma is a benign lipomatous tumor with mature adipocytes, fibrocartilage and fibrous elements. By immunohistochemistry, they show the expression of fat and cartilage markers. No specific molecular genetics changes have been identified so far. Familiarity with its clinicopathological features helps the distinction from its morphologic mimics.
Male ; Female ; Humans ; Adult ; Middle Aged ; Aged ; Desmin/analysis* ; China ; Lipoma/pathology* ; Fibroblasts/pathology* ; S100 Proteins/analysis* ; Diagnosis, Differential ; Fibrocartilage/pathology* ; Biomarkers, Tumor/analysis*

Humans ; Lipoma/pathology* ; Immunohistochemistry

OBJECTIVE: To investigate the value of using MDM2 amplification probe and DDIT3 dual-color, break-apart rearrangement probe fluorescence in situ hybridization (FISH) technique in the diagnosis of liposarcoma. METHODS: In the study, 62 cases of liposarcoma diagnosed in Peking University First Hospital from January 2015 to December 2019 were analysed for clinicopathological information. Of these 62 cases of liposarcoma, all were analysed for MDM2 amplification and 48 cases were analysed for DDIT3 rearrangement using a FISH technique. Our study aimed to evaluate the status of MDM2 and DDIT3 by FISH in liposarcoma and correlate it with diagnosis of different subtypes of liposarcoma. The subtypes of liposarcoma were classified according to the FISH results, combined with the relevant clinicopathological features. RESULTS: The patients aged 31-89 years (mean: 59 years) with a 1.75:1 male to female ratio. Histologically, there were 20 cases of atypical lipomatous tumour/well-differentiated liposarcoma (ALT/WDLPS), 26 cases of dedifferentiated liposarcoma (DDLPS), 13 myxoid liposarcoma (MLPS) and 3 pleomorphic liposarcoma (PLPS). Tumors with DDLPS (23/26) and WDLPS (8/20) were localized retroperitoneally, while both tumours of MLPS and PLPS were localized extra-retroperitoneally, and the difference of sites among the four subtypes of liposarcoma was statistically significant (P < 0.05). Histologically, varied mucoid matrix could be observed in the four subtypes of liposarcoma, and the difference was statistically significant (P < 0.05). MDM2 gene amplification was demonstrated in all cases of ALT/WDLPS and DDLPS (100%, 20/20 and 26/26 respectively); DDIT3 gene rearrangement was noted only in MLPS (100%, 13/13); most cases of DDLPS (96.2%, 25/26) and ALT/WDLPS (83.3%, 5/6, 6 cases selected for detection) demonstrated the picture of amplification of the DDIT3 telomeric tag. According to the instructions of DDIT3 break-apart rearrangement probe, the 5' telomere probe and 3' centromere probe spanned but did not cover the DDIT3 gene itself, on the contrary, the 5' telomere probe covered the CDK4 gene, while the DDIT3 and CDK4 gene were located adjacent to each other on chromosome, therefore, when the amplification signal appeared on the telomeric tag of the DDIT3 rearrangement probe, it indeed indicated the CDK4 gene amplification rather than the DDIT3 gene rearrangement. Then the 10 cases with DDIT3 telomeric tag amplification were selected for CDK4 and DDIT3 gene amplification probe FISH tests, and all the cases showed CDK4 gene amplification (100%, 10/10) and two of the 10 cases demonstrated co-amplification of CDK4 and DDIT3 (20%, 2/10); DDIT3 polysomy detected by DDIT3 gene rearrangement probe was found in 1 case of DDLPS and 2 cases of PLPS (66.7%, 2/3) with morphology of high-grade malignant tumour and poor prognosis. CONCLUSION Our results indicate that a diagnosis of different subtype liposarcoma could be confirmed based on the application of MDM2 and DDIT3 FISH, combined with clinicopathological findings. It is also noteworthy that atypical signals should be correctly interpreted to guide correct treatment of liposarcomas.
Male ; Female ; Humans ; In Situ Hybridization, Fluorescence/methods* ; Cyclin-Dependent Kinase 4/metabolism* ; Liposarcoma/pathology* ; Lipoma/pathology* ; Gene Amplification ; Transcription Factor CHOP/genetics* ; Proto-Oncogene Proteins c-mdm2/metabolism*

Biomarkers, Tumor ; Diagnosis, Differential ; Humans ; In Situ Hybridization, Fluorescence ; Lipoma/genetics* ; Liposarcoma ; Neoplasms, Muscle Tissue/surgery*

Bone Neoplasms/surgery* ; Cartilage Diseases ; Cartilage, Articular ; Humans ; Lipoma/surgery* ; Tibia/surgery*

Introduction: A size of more than 10 cm suggests that a soft tissue tumor might be malignant. Pertinent ancillary diagnostic testing, such as immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), may be done to confirm the diagnosis. Several studies have shown that size may be a useful criterion in determining which tumors are candidates for further molecular testing. MDM2 and p16 are IHC markers for atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS). Objectives: The primary objective of this study is to determine the proportion of tumors signed out as “lipomas” from 2017 to 2019, and measuring at least 10 cm, that express MDM2 and p16 on IHC and warrant revision as ALT/WDLPS. Methodology: This is a descriptive, retrospective cohort study in which all lipomas from 2017 to 2019 that measured at least 10 cm were included. The size, age of the patient, and location of each tumor were documented. The slides of all eligible cases were reviewed and immunohistochemically stained for MDM2 and p16. For each case, the intensity and immunoreactivity of each stain were assessed using a modified, four-tier scoring system. Fisher’s exact test was used to determine if a significant number of tumors expressed MDM2 or p16. Results: Thirty (30) cases satisfied the inclusion and exclusion criteria. The average size of these tumors is 15.10 cm. There is no sex predilection. The most common location of these tumors is the extremities. None of the tumors expressed MDM2, and only one case was p16-positive. The case positive for p16 also showed cytologic atypia and variability in cell size, resulting in the revision of its diagnosis from lipoma to atypical lipomatous tumor. The rate of diagnosis revision after slide review and IHC studies is 3.33%. Conclusion None of the adipocytic tumors that measured at least 10 cm in diameter and were signed out as lipomas was MDM2 positive, and only one case was p16-positive. Thus, morphology remains the cornerstone in the diagnosis of adipocytic tumors. Careful microscopic evaluation is necessary to establish the diagnosis of malignancy in these tumors. Ancillary tests should only be considered in cases where the pathologic features are equivocal.
Neoplasms ; Adipose Tissue ; Lipoma ; Extremities

Lipoma is one of the most common benign tumors in the human body. However, they are uncommon in the oral cavity. Oral lipomas can occur on the cheeks, tongue, lips, gums and rarely on the floor of the mouth. Clinical symptoms are usually asymptomatic yellow masses. Sometimes the tumor grows and can have difficulty speaking and mastication. The treatment of lipoma is surgical excision, and recurrence is rare. We present a case of oral lipoma in an unusal location on the floor of mouth which is rare in the literature.
Cheek ; Gingiva ; Human Body ; Lip ; Lipoma ; Mastication ; Mouth Floor ; Mouth ; Recurrence ; Tongue

Lipoblastoma is a rare benign tumor with 80–90% occurring in children less than 3 years of age and 40% occurring in children less than 1 year of age. The most common site of incidence is limb, and then trunk. Neck is the rare site of incidence. The main symptom that the patient complains about is a rapidly growing neck mass without pain. When the size of mass increases, it can cause dyspnea, Horner's syndrome. Lipoblastoma is usually diagnosed as a lipoma in the fine needle aspiration. Since it is not differentiated from lipoma, liposarcoma, and hibernating adenoma in CT and MRI, the definitive diagnosis is histologic diagnosis through surgical resection. The treatment is complete surgical resection. And recurrence rate is 9–25% due to incomplete resection. Authors report this case with a review of literatures since we experienced a case of lipoblastoma diagnosed histopathologically after surgical treatment of neck mass.
Adenoma ; Biopsy, Fine-Needle ; Child ; Diagnosis ; Dyspnea ; Extremities ; Horner Syndrome ; Humans ; Incidence ; Lipoblastoma ; Lipoma ; Liposarcoma ; Magnetic Resonance Imaging ; Neck ; Pediatrics ; Recurrence

Thoracic outlet syndrome is a relatively well known disease. Other than trauma, this disease is mostly caused by anatomical structures that cause vascular or neural compression. The cause of thoracic outlet syndrome is diverse; however, there are only few reports of thoracic outlet syndrome caused by lipoma in the pectoralis minor space. We report a case of compression of the lower trunk of brachial plexus in which a large lipoma that developed in the pectoral minor space grew into the subclavicular space, along with a review of literature.
Brachial Plexus ; Lipoma ; Nerve Compression Syndromes ; Thoracic Outlet Syndrome

Lipoma is a common benign tumor found at various sites in the body, but it is rarely encountered in the middle ear. We report a case of a 5-month-old girl who presented a middle ear lipoma, which was successfully removed by canal wall up mastoidectomy. To the best our knowledge, this is the youngest case of rare middle ear lipoma, which has ever been reported in the literature.
Ear, Middle ; Female ; Humans ; Infant ; Lipoma ; Otitis Media