Case 1098 - A Male with a Large Left Groin Mass
Contributed by Simmi Patel, MD and Rana Naous, MD
CLINICAL HISTORY
A male, in his 70s, with no prior history of malignancy presented with a large left groin soft tissue mass.
GROSS EXAMINATION
Gross examination revealed a lobulated, cystic, and necrotic mass measuring 17.0 x 16.2 x 12.9 cm with attached skin and skeletal muscle.
MICROSCOPIC EXAMINATION
Tumor was composed of malignant pleomorphic cells with variably sized nuclei, prominent pale eosinophilic to vacuolated cytoplasm and occasionally prominent nucleoli. Scattered pleomorphic lipoblasts were noted focally. Mitotic figures reached up to 52 per 10 HPF, necrosis was estimated at 65%, and lymphovascular invasion was identified. Immunohistochemical stains were patchy positive for desmin, patchy focal for smooth muscle myosin heavy chain and rare weak for SMA. S100, SOX-10, Cytokeratin AE1/AE3, myogenin, CD34, STAT6, ERG, Melanin-A, HMB-45 and MyoD1 were negative. H3K27me3 showed retained expression.
Figure 1, H&E, 2X magnification
Figure 2, H&E, 2X magnification
Figure 3, H&E, 10x magnification. Circled in the image are pleomorphic lipoblasts.
MOLECULAR STUDIES
FISH for MDM2 gene amplification was negative.