Fine-needle Aspiration Diagnosis of Palpable Axillary Lesions: A 4-year Experience at a Busy Outpatient Fine-needle Aspiration Clinic

Introduction: FNA of palpable axillary masses is common, and most cases are presumed to be lymph nodes, with a clinical differential that includes benign lymphadenopathy, lymphoma or metastatic carcinoma. Reporting on the spectrum of palpable axillary lesions subject to FNA appears limited. Materials and Methods: To determine the types of palpable axillary lesions subject to FNA, we reviewed FNA results of all palpable axillary masses that were sampled in the FNA Clinic at the Los Angeles County+University of Southern California Medical Center from 1996 through 1999. Results: 204 cases were identified; 23 (11%) cases were non-diagnostic and excluded from the study. Of the remaining 181 cases, 131 were lymph nodes (72%) and consisted of 62 malignancies (6 Hodgkin lymphomas, 11 non-Hodgkin lymphomas and 45 metastases), 60 reactive lymph nodes and 9 cases of granulomatous lymphadenopathy. Metastatic primaries comprised 33 mammary carcinomas, 4 melanomas, 3 lung carcinomas and 5 carcinomas not otherwise specified (nos). The remaining 50 cases (28%) included 22 lipomas, 8 epidermal inclusion cysts (EICs), 7 cases of biopsy-site changes (e.g., scar, fat necrosis), 5 cases of ectopic breast tissue, 3 abscesses; and 1 each of benign cyst nos, primary apocrine carcinoma, recurrent leiomyosarcoma, schwannoma and a fibrous hamartoma of infancy where the FNA diagnosis was consistent with a "benign spindle cell lesion", with the specific diagnosis rendered histologically. FNA diagnoses were otherwise supported or confirmed by correlation with clinical and available imaging findings, flow cytometry, immunohistochemistry or histology. Conclusions: This study confirms that roughly 2/3 of palpable axillary masses subject to FNA are lymph nodes and most are benign; with most of the malignant diagnoses due to metastatic carcinoma, usually from breast. This study also demonstrates the variety and frequency of non-lymph node lesions to be considered in the differential diagnosis of the remaining 1/3 of palpable axillary masses subject to FNA.