Proximal epithelioid sarcoma: a clinicopathological analysis of 6 cases / 临床与实验病理学杂志

ABSTRACT

Purpose To study the clinicopathological features, immunophenotype and differential diagnosis of proximal epithelioid sarcoma (PES).Methods The clinical, radiological and pathological features were reviewed in 6 cases of PES.Results The patients consisted of five males and one female with ages ranging from 32 to 74 years (mean 56 years). Clinically, the tumor mass were progressively-growing solitary nodules with the fuctional disorder and pain. The sites of the tumor involvement were buttock (1 case), thigh (2 cases), iliac spine (1 case), lumbar spine (1 case) and anterior sacrum (1 case). Histologically, the tumors were mainly consisted of epithelioid cells with round or oval nuclei, prominent nucleoli and eosinophilic cytoplasm, some tumor cells appeared rhabdoid features. Immunohistochemically, the tumor cells were positive for vimentin (6/6), CK (5/6), EMA (6/6),β-catenin (6/6), CD99 (5/6), and CD34 (4/6), but negative for S-100 protein, HMB 45, CD 117 and CD 31.Conclusion PES is a distinctive moderate grade malignant tumor with prominent epithelioid and rhabdoid cells appearance.The differential diagnoses include the tumors that have similar cellular appearance with PES, and immunohistochemical staining is useful for diagnosis and differential diagnosis.