Primary Sclerosing Epithelioid Fibrosarcoma of the Kidney: A Case Report and Review of the Literature

Sclerosing epithelioid fibrosarcoma (SEF) is a rare variant of fibrosarcoma. We report one case of primary kidney SEF occurring in a 38-year-old man. Microscopically, epithelioid neoplastic cells are mainly arranged in cords and nests embedded in the dense sclerosing stroma. Diffuse immunohistochemical staining for MUC4 in neoplastic cells and the presence of the EWSR1 gene split by fluorescence in situ hybridization (FISH) analysis confirmed the histological diagnosis. Primary kidney SEF is extremely rare, the differential diagnosis strategy broadly includes a series of tumors with epithelioid morphology and sclerosing matrix, mainly including sclerosing variants of clear cell sarcoma of the kidney (CCSK), renal synovial sarcoma (SS), renal solitary fibrous tumor (SFT), metanephric stromal tumor (MST), sclerosing perivascular epithelioid cell tumor (PEComa), and carcinomas, and immunohistochemical expression of MUC4 and evidence of the EWSR1 gene split are helpful in making a definite diagnosis.

Sclerosing Epithelioid Fibrosarcoma; A Case report and review of literature

Introduction/Objective Sclerosing Epithelioid Fibrosarcoma (SEF) is an unusual, rare clinically aggressive form of soft tissue sarcoma. It is characterized by a slow evolution, with local recurrences and late metastases that are mainly pulmonary and pleural in about 80% of cases. SEF has distinctive morphology and occurs most commonly in deep soft tissue of adult extremities. Lesions involving the head and neck region are uncommon and rare intraosseously in oral cavity. Methods/Case Report Herein we report a case of a 52-year-old male who presented with a symptomatic radiolucent lesion at apex #18, with clinical impression of periapical granuloma. The patient did present with pain associated with lower left quadrant #18 area, for several days to pressure and hot temperature. A periapical radiograph revealed a large ill-defined radiolucent area at apex of resorbing roots #18. The patient’s medical history was significant with history of cancer diagnosis of sclerosing epithelioid fibrosarcoma of skull treated by chemotherapy and radiation. Microscopic examination of the specimen revealed a multi-fragmented specimen consisting of numerous fragments and islands of highly cellular, basophilic bone and osteoid surrounded by loose fibrous stroma which contains large lobules and islands of round to oval cells, with distinct cell borders and faintly granular eosinophilic cytoplasm. Separate islands of tumor cells surround large islands of necrosis with the background stroma appearing as hyalinized and eosinophilic with the basaloid cells demonstrating smudge and crush artifact. Peripherally, spindled cells are noted and faint areas of eosinophilic osteoid within the eosinophilic background stroma. Lesional cells are MUC4 strong, diffusely positive and strongly positive for INI-1. CD43, CD20, PAX-5, CD3, Desmin, CD34, S100, CD99, AE1/3 and SMA are interpreted to be negative. A diagnosis of metastatic sclerosing epithelioid fibrosarcoma was made, with correlation with the primary lesion was recommended. Results (if a Case Study enter NA) N/A Conclusion The clinical and histological findings of our case correlate with the diagnostic criteria of sclerosing epithelioid fibrosarcoma. Despite its microscopic features can create diagnostic difficulties, in that SEF can resemble a variety of benign and pseudosarcomatous as well as malignant lesions, our case diagnosis was confirmed by morphology and MUC4 diffuse strong reactivity and negativity for other markers.

Sclerosing Epithelioid Fibrosarcoma of the Kidney: First Reported Case in a Young Child

Sclerosing epithelioid fibrosarcoma (SEF) is a rare variant of fibrosarcoma primarily arising in the deep soft tissue of the extremities and trunk. Despite having the morphologic appearance of a low-grade sarcoma, it generally has an aggressive clinical course with frequent local recurrences and distant metastases. It typically occurs in middle aged adults and is characterized by immunoexpression of MUC4 and recurrent gene fusions, most commonly EWSR1-CREB3L1. We report a primary renal SEF in a 4-year-old male. To our knowledge, this is the youngest patient reported with SEF and the second case of SEF in a pre-adolescent child. It is the eleventh reported case of primary renal SEF in the literature. While SEF arising in visceral organs is rare, the kidney is the most common primary site of any visceral organ. This case demonstrates SEF can occur in pre-adolescents, is an important consideration when evaluating sarcomas in young children, and should be considered in the differential diagnosis for primary renal tumors.