The objective of this study was to determine the utility of fine-needle aspiration biopsy (FNAB) in the primary diagnosis of mesenchymal lesions. A total of 162 cases with a diagnosis of benign or malignant mesenchymal lesion (excluding lipoma) on FNAB were retrieved from the cytopathology archives for the years 1990-1997.
Patients selected for inclusion in this study underwent FNAB as the primary diagnostic modality without a previous tissue diagnosis and had a subsequent surgical procedure for definitive histologic correlation. Seventy-two patients were selected on the basis of the above criteria.
Cytologic diagnoses were categorized as benign, malignant, or suspicious for malignancy. Among the 72 cases selected, 42 (58%) benign, 18 (25%) malignant, and 12 (16%) suspicious diagnoses were rendered. Of the patients with benign FNAB diagnoses, 39 of 42 (93%) had a benign lesion on histologic follow-up, and 3 of 42 (7%) had a malignancy. Of the patients with malignant FNAB diagnoses, 17 of 18 (94%) had a malignant lesion and 1 of 17 (6%) proved to be benign. In the subset of suspicious lesions, subsequent histology was benign in 5 of 12 (42%) and malignant in 7 of 12 (58%).
Based on our study, FNAB has excellent accuracy (88%), sensitivity (89%), and specificity (87%) for classifying a mesenchymal tumor as benign or malignant. FNAB can be a rapid and effective tool for the primary categorization of mesenchymal lesions and provide reliable information to the clinician for triage of patients.