Cytologic features of extragonadal germ cell tumors

Abstract

The objective of the current study was to evaluate and describe the cytologic features of extragonadal germ cell tumors (GCTs), both primary and metastasis from gonadal sites, in fine-needle aspiration cytology. Aspirates from 88 extragonadal GCTs were retrieved with their clinical features and cytologic smears. The smears were assessed for cellularity, cell patterns, and cytologic features, which were summarized. Histopathology was available in 47 cases, and cytohistologic correlation was done in all such cases. Of 88 cases, 57 with adequate cytologic material were analyzed. Each type of GCT, except for embryonal carcinoma, had characteristic morphologic features. Seminomas had dyscohesive tumor cells with well defined, vacuolated cytoplasm; prominent nucleolus; and background lymphocytes. 'Tigroid' background was noted in only a minority of cases. Yolk sac tumors revealed papillary fragments of tumor cells with metachromatic basement membrane-like material in the fragments. Mixed germ cell tumors were difficult to diagnose except for cases in which more than 1 type of GCT was observed on cytologic smears. In 37% of cases with mixed GCT, only 1 component was observed on cytology. Fine-needle aspiration cytology can reliably offer a diagnosis of GCT at extragonadal sites, even in rare locations and in patients in whom metastatic tumor may be the first clinical presentation. Immature teratoma and mixed GCTs pose a significant problem in cytology because of sampling error on needle aspiration. At extragonadal sites, the list of differential diagnoses is wider than that for gonadal GCTs.