Cytokeratin 7 and 20 expression in epithelioid sarcoma

Abstract

Background: Epithelioid sarcoma (ES) is a rare malignant soft tissue tumor of uncertain histogenesis that arises predominantly in the extremities of young adults. Immunohistochemically, the neoplastic cells are typically positive for vimentin, low molecular weight cytokeratin (CAM5.2) and epithelial membrane antigen (EMA). Method: We examined eight cases of ES from seven different patients. All cases were studied with immunohistochemistry for EMA, CAM5.2 (keratin 8 and 18), 34BE12 (keratins 1, 5, 10 and 14/15), cytokeratins 7 and 20 (CK7, CK20), and CD34. Results: The average patient age was 53 (range 43–76) and the male:female ratio was 5:2. The location was the upper extremity in five tumors, the lower extremity, the perineum, and the paraspinal soft tissue in one tumor each. All cases contained predominantly epithelioid cells, but spindle cells were also present in three cases. All cases contained areas of geographic necrosis. CAM5.2 was strongly positive in seven tumors and focally positive in one (8/8). EMA was diffusely positive in two cases and focally positive in five cases (7/8). CD34 was diffusely positive in 3/8 cases. 34BE12 was diffusely positive in one case and focally positive in two others (3/8). CK7 was diffusely positive in one case and focally positive in another (2/8). CK20 was negative in all cases (0/8). All cases tested were positive for vimentin (6/6), 2 cases were focally positive for HHF35 (2/5), and all cases tested were negative for S‐100 protein (0/7). Conclusions: In addition to the known immunoreactivity for CAM5.2 and EMA, there is positivity for CK7 and 34BE12 in a small proportion of cases. None of the cases expressed CK20. This immunophenotypic profile suggests that ES is more similar to carcinoma and synovial sarcoma than to other soft tissue tumors, and may be of diagnostic utility.

Proximal‐type epithelioid sarcoma in a 36‐year‐old man: Closer immunoelectron‐microscopic resemblance of the tumor cells to epithelial cells than to mesenchymal cells

“…Immunohistochemical analysis is necessary for the diagnosis of PES. Proximal‐type epithelioid sarcoma is antigenically identical to classical ES, 1 and both express cytokeratin, vimentin, EMA and CD34 1–3,5 . In the present case, the tumor occurred in the perineal subcutis of a man in early middle age and the tumor cells showed rhabdoid features.…”

“…Proximal-type epithelioid sarcoma is antigenically identical to classical ES, 1 and both express cytokeratin, vimentin, EMA and CD34. [1][2][3]5 In the present case, the tumor occurred in the perineal subcutis of a man in early middle age and the tumor cells showed rhabdoid features. Furthermore, the tumor cells expressed cytokeratin, vimentin, EMA and CD34.…”

Epithelioid Sarcoma

“…Only a minority of reported cases have shown positive staining for CD31, most of them in a focal pattern 11 . Recently, ES has also been found to be consistently positive for the expression of Keratin 8 11 but negative for CK20 15 …”

“…11 Recently, ES has also been found to be consistently positive for the expression of Keratin 8 11 but negative for CK20. 15 ES may simulate a palisaded granulomatous process. The latter lacks expression for epithelial markers like cytokeratins and EMA but consistently expresses CD68.…”

“…Cytokeratin subtyping has been demonstrated to be of diagnostic value in this differentiation. 11,15 The consistent expression of cytokeratin 5/6 in squamous cell carcinomas but not in ES has been suggested as a marker for their distinction. 13,16 Malignant melanomas are typically negative for cytokeratin expression.…”