Browsing by Subject "Liposarcoma"

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    Atypical spindle cell/pleomorphic lipomatous tumor
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Lecoutere, Evelyne; Creytens, David
    Atypical spindle cell/pleomorphic lipomatous tumor (ASPLT) is a recently described morphologically low-grade and clinically indolent adipocytic tumor, which will be incorporated as a new tumor entity in the upcoming 5th edition of the WHO Classification of Soft tissue and Bone tumors. Histologically, ASPLTs are characterized by ill-defined tumor margins and the presence of variable proportions of mild-to-moderately atypical spindle cells, adipocytes, lipoblasts, pleomorphic multinucleated cells and a myxoid or collagenous extracellular matrix. ASPLTs can show a wide variety of microscopic appearances and there is histologic overlap with diverse mimics. The diagnosis of ASPLT can therefore be challenging. Molecular studies have shown a consistent absence of MDM2 or CDK4 amplification. On the other hand, deletions or losses of 13q14, including RB1, have been identified in a significant subset of cases. This review provides an overview of the currently known clinical and pathological features of ASPLTs, detailing its most relevant differential diagnoses.
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    CD34-positive myxoid sarcoma of the retroperitoneum; a dilemma in differential diagnosis of multiple biopsy specimens
    (Murcia : F. Hernández, 2010) Terada, Tadashi
    The author reports a case of CD34-positive malignant myxoid sarcoma in the retroperitoneum with a dilemma of differential diagnosis in multiple biopsy specimens of different locations. A 79-year-old man was diagnosed with right renal pelvic carcinoma and nephrectomy was performed. The carcinoma was urothelial carcinoma (2cm in diameter) without invasion. The patient was followed up, and a large retroperitoneal tumor was found two years after the operation. Multiple needle biopsies were performed. The patient then showed a hepatic metastasis, and died of cachexia one year after the detection of the retroperitoneal tumor. The needle biopsy specimens showed spindle cell sarcoma in the myxomatous stroma (80%) and in the nonmyxomatous stroma (20%). Immunohistochemically, the tumor cells were positive for vimentin, CD34, CD99, bcl-2 and p53 protein. They were negative for cytokeratins, desmin, α-smooth muscle actin, S100 protein, melanosome, CEA, neuron specific enolase, CD68, factor VIII-related antigen, CD31, KIT, and PDGFRA. Ki67 labeling was 30%. A genetic analysis for KIT gene (exons 9, 11, 13 and 17) and PDGFRA gene (exons 12 and 18) showed no mutations. Although the differential diagnosis is problematic and difficult, the present case is probably dedifferentiated liposarcoma. The needle biopsy diagnosis of sarcomas is difficult and limited because sarcomas show heterogenous histologies with regard to locations in the same tumor.