Cytomorphologic spectrum of giant cell tumor of tendon sheath

OBJECTIVE: To correlate the cytomorphologic spectrum of giant cell tumor of tendon sheath (GCTTS) with clinical and histologic findings and determine key features helpful in preoperative diagnosis. STUDY DESIGN: Retrospective analysis was done on 48 cases diagnosed cytologically over 9 years. Cases were divided into 2 groups: in group 1 cytology and histology were available (12), and in group 2 cytology alone was available (36). Cytomorphologic features were correlated with clinical and histologic findings. RESULTS: Patients ranged in age from 11 to 60 years, with more women. Small joint involvement was seen in all cases except 1, with upper limb involvement in most cases. Recurrence occurred in 3 cases. Aspiration smears in all cases showed high cellularity, multinucleated osteoclastic type of giant cells and stromal cells. Other features seen less frequently were cytoplasmic granules and vacuoles, nuclear grooves, inclusions, budding, focal mild pleomorphism, hemosiderin-laden macrophages and foam cells. Mitosis and necrosis were absent. Cytologic features were classified as constant when present in all cases and variable when present occasionally. CONCLUSION: The constant cytologic features when combined with clinical and radiologic details are sufficiently distinctive of GCTTS. Fine needle aspiration cytology can be used in early, accurate preoperative diagnosis.