The clinicopathological spectrum of sclerosing epithelioid fibrosarcoma: report of an additional series with review of the literature

We present a case series of sclerosing epithelioid fibro-sarcoma (SEF) to further characterise its clinical and pathological features. Twenty-one patients with SEF were included in this study. There were 12 males and nine females (range 25-63 years; median 38 years). Tumours were located in the kidney (n=5), thigh (n=3), chest wall (n=3), head and neck (n=2), bone (n=2), abdominal wall (n=1), psoas major (n=1), retroperitoneum (n=1), omentum (n=1), popliteal space (n=1) and lung (n=1). Tumour sizes ranged from 2.5 to 16 cm (median 7 cm). Microscopically, epithelioid tumour cells were arranged in nests and cords and embedded in a dense sclerotic stroma. Some tumours showed myxoid areas, fibroma-like areas, acinar growth patterns and haemangiopericytoma-like appearance. A few tumour cells presented a rhabdomyoid shape. Calci-fication, ossification, cystic and necrosis were observed in some cases. The diagnosis was confirmed by immunore-activity for MUC4, and by further fluorescence in situ hybridisation (FISH) or next generation sequencing (NGS) analysis. Clinical follow-up was available for 16 cases (median, 24 months; range 6-62 months). Seven patients developed metastases to lung (n=3), bone (n=3), brain (n=2) and back (n=1). Four patients developed a local recurrence. Three patients died of disease. Overall sur-vival (OS) of SEF was related to patient age (p=0.001) and progression-free survival (PFS) was related to tumour size (p=0.046).In addition to soft tissue, SEF is more likely to involve the viscera and the abdominal cavity and has morphological variants. Familiarity with its distinctive clinical and patho-logical features helps avoid misdiagnosis.