The fine needle aspiration of translocation sarcomas

INTRODUCTION: Soft tissue sarcomas comprise a heterogeneous group of clinically aggressive cancers that are often hard to classify on limited cytological samples. "Translocation sarcomas" (TS) are a diverse subset of such cancers, different from pleomorphic sarcomas, and characterised by unique single chromosomal translocations in each sarcoma subtype. Interestingly, despite their high-grade biological behaviour, TS have deceptively monotonous and bland cytomorphology, therefore creating diagnostic issues on limited samples. MATERIALS AND METHODS: A retrospective search was conducted of the cytopathology archives of The Johns Hopkins Hospital revealing 147 translocation sarcoma cases over a 25-year period. RESULTS: The common morphological denominators for most translocation sarcomas were: hypercellularity, cellular monotony, mostly discohesive and single cells, round-to-oval or short spindled cells and a lack of necrosis. The exceptions were an inflammatory myofibroblastic tumour, in which cellular monotony was not present owing to the prominence of lymphocytes and plasma cells, and low-grade fibromyxoid sarcoma, in which the specimens were generally hypocellular. Ancillary testing, especially immunoperoxidase staining, was often required for primary lesions. CONCLUSION: Distinct morphological clues and subsequent ancillary testing (particularly immunoperoxidase staining) provide an accurate diagnosis on cytological interpretation of both, primary and recurrent/metastatic lesions.