Objective: To perform a comparative analysis of fine needle aspiration cytology (FNAC) features of chondroid tumors and their significance in diagnosis.
Study design: A retrospective evaluation of 17 chondroid tumors diagnosed by FNAC was done. Cytologic features were detailed and compared among different chondroid tumor types and with available histology.
Results: The 17 cases comprised enchondroma (5), osteochondroma (1), chondroblastoma (2), chondromyxoid fibroma (2) and chondrosarcoma (7). Chondroblastoma and chondromyxoid fibroma were specifically diagnosed in all 4 cases by FNAC due to characteristic cytology. However, the cytologic appearance of enchondromas overlapped significantly with that of well-differentiated chondrosarcoma, but the correct diagnosis was made by interpreting cytology with clinicoradiologic correlation. The cytologic features of high chondroid fragment cellularity, irregular cell arrangement in fragments, prominent nucleoli, and moderate to severe nuclear hyperchromasia and mitotic activity were limited to chondrosarcoma. The single error consisted of a case of osteogenic sarcoma, chondroblastic type, that was interpreted as chondrosarcoma.
Conclusion: FNAC smears interpreted in the light of clinical and radiologic findings demonstrated high diagnostic accuracy. It is important to be aware of the cytology of uncommon chondroid tumors such as chondroblastoma and chondromyxoid fibroma as well as of the overlap of cytologic features between enchondroma and chondrosarcoma to avoid diagnostic pitfalls.