The role of fine-needle aspiration cytology in the evaluation of metastatic clear cell tumors

BACKGROUND, Clear cell tumors (CCTs] occur as primary neoplasms in a number of anatomic sites. Due to their overlapping morphologic features, these tu mors can be challenging for the cytologist, particularly when they present as metastatic lesions. METHODS. Forty-nine fine-needle aspirations (FNA) of metastatic CCTs from 4 6 patients (age range, 29-87 years; mean, 64 years) were reviewed retrospec tively. In addition to the routine smears and cell block preparations, anci llary studies were performed in selected cases. Clinical and/or histologic follow-up was obtained for all patients. RESULTS. The sites of the 49 FNAs were the lung (12 cases), lymph nodes (9 cases), liver (7 cases), bone (7 cases), soft tissue (4 cases), pelvis (2 c ases), adrenal gland (2 cases), pancreas (1 case), thyroid (2 cases), perit oneum (2 cases), and vagina (1 case). Twenty-seven patients had a previous history of a CCT and the FNA material in these cases was consistent with a metastasis. The primary anatomic sites in these cases were the kidney (20 c ases), ovary [2 cases), salivary gland (I case), and cervix (1 case). On li ght microscopy, these tumors had a similar appearance and often were indist inguishable. Nineteen patients did not have a prior history of malignancy; 12 of these patients had a concurrent renal mass and the diagnosis of metas tatic renal cell carcinoma was made. The anatomic site of origin of seven o f the ten remaining tumors (kidney [2 cases], lung [2 cases], ovary [1 case ], germ cell [1 case], and endometrium [1 case]) was established through im munocytochemical studies of cytologic material and clinical follow-up. CONCLUSIONS. FNA plays an important role in the diagnosis of metastatic CCT . Cytologic examination, ancillary studies, and clinical information can es tablish the anatomic site of origin in the majority (95%) of cases, preclud ing the necessity of obtaining additional tissue. Cancer (Cancer Cytopathol ) 1999;87:380-9. (C) 1999 American Cancer Society.