Proximal-Type Epithelioid Sarcoma With Elevated Serum CA 125: Report of a Case With CA 125 Immunoreactivity

Archives of Pathology & Laboratory Medicine, Jun 2006 by Lee, Hyang-Im, Kang, Kil Hyun, Cho, Young Mee, Lee, Oak-Jun, Ro, Jae Yoon

Our patient had a pelvic mass with an initial serum CA 125 level elevated up to 3395 U/mL; the level decreased to 452 U/mL after surgery. Clinically, the pelvic mass was considered as an ovarian neoplasm because of the pelvic mass and elevated serum CA 125 level. However, histologie and immunohistochemical findings of the tumor were identical to those of proximal-type epithelioid sarcomas. In addition, the immunohistochemical staining for CA 125 in the tumor cells was also positive. The result of the decreased serum level after surgery and a positive immunoreactivity of CA 125 in the tumor cells indicate that elevation of the serum CA 125 level was caused by secretion from the tumor cells of proximal-type epithelioid sarcoma in our patient. Based on the reports of Kato et al,3,4 as well as our findings, if epithelioid sarcoma or proximal-type epithelioid sarcoma is suspected, measurement of the serum CA 125 level and an immunohistochemical study of CA 125 are strongly recommended in the absence of good current markers to discriminate epithelioid sarcoma from its histologie mimickers, such as extrarenal rhabdoid tumor and undifferentiated carcinoma, and for monitoring its clinical course. Although mesenchymal tumors such as alveolar rhabdomyosarcoma and desmoplastic small round cell tumor can be positive for CA 125(14,15) and can also have rhabdoid features, these tumors generally are morphologically different, and immunohistochemical studies including MyoD1, desmin, and myogenin help to differentiate these tumors from-proximal type epithelioid sarcoma.

References

1. Guillou L, Wadden C, Coindre JM, et al. "Proximal-typo" epithelioid sarcoma: a distinctive aggressive neoplasm showing rhabdoid feature's, clinicopathologic, immunohistochemical, and ultrastructural study of a series. Am J Surg Pathol. 1997;21:130-146.

2. Miettinen M, Fanburg-Smith JC, Violainen M, et al. Epithelioid sarcoma: an immunohistochemical analysis of 112 classical and variant cases and a discussion of the differential diagnosis. Hum Pathol. 1999;10:9.14-942.

3. Kato H, Halori M, Watanabe M, Kokuhun S. Epithelioid sarcoma with elevated serum CA125: report of two cases. Jpn J Clin Oricol. 2003;33:141-144.

4. Kato H, Hatori M, Kokuhun S, et al. CA125 expression in epithelioid sarcoma. Jpn J Clin Omol. 2004;14:149-154.

5. Enzinger FM. Epithelioid sarcoma: a sarcoma simulating a granuloma or a carcinoma. Oincer. 1970;26:1029-1041.

6. Mirra JM, Kessler S, Bhuta S, et al. The fibroma-like variant of epithelioid sarcoma: a fibrohistiocytic/myoid cell lesion often confused with benign and malignant spindle cell tumors. Gincer. 1992;69:1382-1395.

7. Von Hochstetter AR, Meyer VE, Grant JW, et al. Epithelioid sarcoma mimicking angiosarcoma: the value of immunohistochemistry in the differential diagnosis. Virchows Arch A Pathol Anat Histopathol. 1991;418:271-278.

8. Hasegawa T, Matsuno Y, Shimoda T, et al. Proxiinal-type epithelioid sarcoma: a clinicopathologic study of 20 cases. Mud Pathol. 2001;14:655-663.