Extrauterine epithelioid trophoblastic tumors presenting as primary lung carcinomas: morphologic and immunohistochemical features to resolve a diagnostic dilemma.

Our objective was to describe the clinicopathologic features of epithelioid trophoblastic tumors (ETTs) in a series of patients who presented with elevated beta-human chorionic gonadotrophin (hCG) levels and extrauterine lesions resembling primary lung carcinomas. Clinical and pathologic materials were reviewed and Shih and Kurman's diagnostic criteria were applied. Three parous women (38, 49, and 34 y of age) with elevated beta-hCG levels had nondiagnostic gynecologic evaluations, including negative dilation and curettage specimens. Imaging revealed isolated pulmonary lesions, 2 to 8.5 cm in size, resembling primary lung carcinomas. Two patients received multiagent chemotherapy consisting of etoposide, methotrexate, dactinomycin, alternating with cisplatin and etoposide, and all underwent pulmonary resection. Histologically, the cytologic features, epithelioid growth pattern, and hyaline-like material simulated the appearance of nonsmall cell lung carcinoma, but overall, the histologic features along with the immunophenotype supported classification as ETT. Follow-up hysterectomy specimens were histologically normal. All 3 patients are alive and well. The rarity of ETT and its resemblance to squamous and pleomorphic carcinomas of lung have led to diagnostic difficulties. When reproductive-age women present with elevated beta-hCG levels, a pulmonary lesion, and no apparent intrauterine disease, primary pulmonary ETT should be considered. Correlating clinical indices with specific morphologic and immunohistochemical features can ensure diagnostic accuracy and appropriate treatment for favorable outcomes.