Cytopathologic diagnosis of extragonadal germ cell tumors: A 10-year institutional review.

BACKGROUND: The occurrence of extragonadal germ cell tumors (EGGCTs), either as primary tumors or metastatic disease, is rare. Forms of cytologic sampling, including fluid analysis, fine-needle aspiration, and/or small-core needle biopsy, have been shown to be reliable methods for the diagnosis of germ cell tumors. This study aims to investigate the utility of cytopathologic techniques in the diagnosis of EGGCTs at the authors' institution. METHODS: The laboratory information system was queried over a period of 10 years (2012-2022) to identify all cytology cases diagnosed on fluid cytology, FNA, and/or small-core biopsy as germ cell tumors in extragonadal locations. Patient demographics, tumor location, serum tumor marker levels, cytopathologic diagnosis, and follow-up surgical resection data were reviewed and correlated. RESULTS: A total of 35 cases from 32 patients (all males) were identified. Thirty specimens contained satisfactory material for diagnosis (86%) and five were less than optimal for evaluation (14%). Despite this, all cases had clinically useful cytopathologic diagnoses. A total of 19 cytology cases (16 patients) had follow-up resection specimens available. Of these, 11 patients underwent preoperative chemotherapy. Nine patients showed no evidence of residual tumor and two showed histologic concordance. Of the five patients who did not have preoperative chemotherapy, all showed concordant histologic diagnoses. CONCLUSIONS: Cytology can provide a reliable, accurate method for diagnosing EGGCTs. The practice of preoperative (neoadjuvant) chemotherapy places an extreme importance on the initial cytopathologic diagnosis because the majority of patients with follow-up resection in this series showed no residual tumor.