Utility of fine needle aspiration cytology (FNAC) in the diagnosis of soft tissue tumors and tumor like lesions

Introduction: Fine needle aspiration cytology (FNAC) forms one of the first diagnostic tools in evaluation of soft tissue lesions. Aim of this study was to evaluate the role of FNAC in the primary diagnosis of soft tissue tumors and tumor like lesions and to assess the effectiveness of FNAC in the histological subtyping and grading of soft tissue tumors. Materials and Methods: We reviewed FNAC smears of 170 soft tissue tumors and tumor like lesions over a 3 years period and correlated with the histopathological features which were available in 117 cases. Conventional Papanicolaou (PAP) and Giemsa staining was done in all cases. Results: 152 out of 170 cases [89.41%] were neoplastic, of which 130 tumors were labelled as benign. Lipoma constituted 83.07% of benign tumors. Based on the predominant cytomorphological features and background, the tumors were classified into myxoid (4), spindle cell (20), pleomorphic (2), small round cell(4), epithelioid /polygonal cell (7), lipomatous (108) and miscellaneous (7). The non-neoplastic lesions included tuberculosis, filariasis, actinomycosis, scar endometriosis and calcinosis cutis. Conclusion: FNAC proved to be helpful in distinguishing between neoplastic and non-neoplastic soft tissue lesions, differentiating metastatic carcinoma and melanoma in soft tissue from primary soft tissue tumors and differentiating benign and malignant soft tissue tumors. Accurate subtyping was possible in many tumors of myxoid category and round cell tumors. Spindle cell tumors of intermediate grade were difficult to grade on FNAC. Pleomorphic sarcomas were of high grade and their subtyping could not be done on FNAC.