Proximal-Type Epithelioid Sarcoma: A Clinicopathologic Study of 20 Cases

Abstract

We studied the clinicopathologic and immunohistochemical features of 20 cases of proximal-type epithelioid sarcoma to identify prognostic factors. The 20 patients ranged in age from 13 to 80 years (mean, 40 y); 12 patients were male and 8 were female. The tumors presented as deep soft-tissue or subcutaneous masses on the inguinal region in five, the thigh in four, the vulva in three, the axilla in three, and one each in the flank, chest wall, back, hip and perineum. The tumors ranged from 2 to 16 cm at their greatest diameter (mean: 7.8 cm). Histologically, 12 tumors (60%) were classified as the large-cell subtype, characterized by sheets of large cells with prominent nucleoli resembling poorly differentiated carcinoma, and a frequent rhabdoid phenotype, six (30%) were classified as the conventional subtype, and two ( Epithelioid sarcoma, first described by Enzinger in 1970 (1), is a rare soft-tissue sarcoma typically presenting as a subcutaneous or deep dermal mass in distal portions of the extremities of adolescents and young adults. Microscopically, most tumors are characterized by a granuloma-like pattern: nodules of spindled and epithelioid cells circumscribe areas of central hyalinization and necrosis. Fibrous histiocytoma-like and angiomatoid subtypes have also been reported as less common histologic variants (2, 3). Patients often develop multiple local recurrences of long duration, with subsequent metastases in 30 to 50% of cases (4). A more aggressive "proximal" or largecell type has been described in rare cases to occur as a deep-seated soft-tissue mass at proximal body sites and to show sheets of large cells with prominent nucleoli resembling a poorly differentiated carcinoma and a frequent rhabdoid phenotype (5). Thus, this tumor must be distinguished from other epithelioid lesions, such as extrarenal rhabdoid tumor, synovial sarcoma, angiosarcoma and melanoma, and its prognostic factors have not yet been fully investigated. We therefore studied 20 cases of proximal or axial epithelioid sarcoma by immunohistochemical analysis to examine the clinicopathologic features that correlate with a poor outcome in patients with these tumors.

Prognostic significance of dysadherin expression in epithelioid sarcoma and its diagnostic utility in distinguishing epithelioid sarcoma from malignant rhabdoid tumor

“…In contrast, proximal-type epithelioid sarcoma typically reveals a diffuse proliferation of large epithelioid carcinoma-like cells with marked cytologic atypia and frequent occurrence of rhabdoid features (large cell type) (Figure 1c and d). As described by Hasegawa,8 proximal-type epithelioid sarcoma are classified into three histologic subtypes (large cell type, conventional type and angiomatoid type). In the current study, both distaltype epithelioid sarcoma and proximal-type epithelioid sarcoma were classified into three histologic subtypes.…”

“…2,3,6 Some authors 7 have described proximal-type epithelioid sarcoma as being a variant of extra-renal malignant rhabdoid tumor, while other authors 2,8,9 have demonstrated that both tumors are distinctly different entities. Some data exist regarding the histological and immunohistochemical differences between the proximal-type of epithelioid sarcoma and malignant rhabdoid tumor, but such findings have not yet been found to be conclusive.…”

Epithelioid leiomyosarcoma of uterine cervix: A case report with immunohistochemical study

“…This variant is located centrally, and has much more atypia and poor biological behaviors. [17][18][19] Although the diagnosis is not complete, the author thinks that the present tumor is not this variant of epithelioid sarcoma because there have been no reports that showed smooth muscle antigens in this variant, and angiomatoid form and classical form of epithelioid sarcomas.…”

Epithelioid sarcoma: A case series of three different presentations

“…S-100 and CD31 are Negative, while Desmin, CA125 and CD34 are positive in some cases. [11] Here, the epithelial marker Vimentin was positive in all of them while AE 1 and EMA were positive in two. The battery of markers to be tested was chosen based on clinical picture and microscopic appearance to rule out other differential diagnosis (see Table 1).…”

“…[10] It typically shows large cells with prominent nucleoli, marked cytological atypia and intracytoplasmic hyaline inclusions. [11] These together impart a "RHABDOID" appearance to this variant. Though tumour necrosis occurs, it seldom results in granuloma like appearance unlike a "classical" variant.…”