CYTOLOGIC FEATURES OF SARCOMAS IN FLUIDS

BACKGROUND. Sarcomas account for < 6% of malignant effusions and their diagnosis usually is made in the setting of a known primary tumor. Ho wever, these tumors often exhibit a variety of features that can diffe r from those of the original neoplasm and may preclude the correct dia gnosis. This article evaluates the cytomorphology of sarcomas in fluid s and determines characteristic features for identification and classi fication. METHODS. The study included 24 Papanicolaou-stained fluid sa mples (15 pleural, 8 peritoneal, and 1 pericardial) from patients with a diagnosis of sarcoma. The following features were evaluated: cellul ar arrangement, cellularity, nuclear/cytoplasmic ratio, background, qu ality and quantity of cytoplasm, cell borders, and nuclear details. RE SULTS. All cytology specimens were diagnosed accurately as malignant. The histopathologic diagnoses were eight malignant fibrous histiocytom as, five leiomyosarcomas, three rhabdomyosarcomas, three liposarcomas, two high grade sarcomas, one osteogenic sarcoma, one synovial sarcoma , and one chondrosarcoma. Cytomorphologic features shared by sarcomas in metastatic sites included single cell arrangement (23 of 24; 95.8%) , indistinct cell borders (18 of 24; 75.0%), nuclear pleomorphism (18 of 24; 75.0%) multinucleation (13 of 24; 54.2%), and proteinaceous bac kground with lysed blood (17 of 24; 70.8%). CONCLUSIONS. Sarcomas in e ffusions share morphologic features that allow their correct diagnosis . Further subclassification can be attempted in the proper clinical (C ) 1998 American Cancer Society.