SMALL ROUND-CELL TUMORS OF THE ABDOMEN AND THORAX - ROLE OF FINE-NEEDLE ASPIRATION CYTOLOGIC FEATURES IN THE DIAGNOSIS AND DIFFERENTIAL-DIAGNOSIS

OBJECTIVE: To evaluate the role of cytomorphologic features in the dia gnosis and differential diagnosis of small round cell tumor (SRCT) of the abdomen and thorax. STUDY DESIGN: During a period of six years (19 85-1940), ultrasound/computed tomography-guided fine needle aspiration cytology was performed on thoracic and abdominal/pelvic masses in 899 cases. Slides were not available for review in 28 cases. Review of sm ears by one of the investigators (D.K.D.) in the remaining cases, whic h included 239 with intrathoracic and 632 with intraabdominal/pelvic m asses, yielded 380 (43.6%) cases of malignancy. Of these, 72 (18.7%) c ases were small round cell tumors. In 59 cases of SRCT the smears were found suitable for detailed assessment of cytomorphologic features. R ESULTS: The 59 cases of small round cell tumors included 5 cases of ne uroblastoma, 7 of hepatoblastoma, 4 of nephroblastoma, 1 of pulmonary blastoma, 2 of Ewing's sarcoma, 23 of non-Hodgkin's lymphoma (NHL), 15 of small cell anaplastic carcinoma (SCAC), 1 NHL/SCAC and 1 small rou nd cell tumor (not otherwise specified). The frequencies of rosettes ( 60%) and filamentous/fibrillar matrix (100%) in neuroblastoma; acinar formation in hepatoblastoma (100%) and SCAC (93.3%); tubule formation in nephroblastoma (100%); lipid vacuoles (69.6%), exclusive noncohesiv e cells (95.7%) and lymphoglandular bodies (87%) in NHL; and nuclear m olding (100%) and paranuclear blue inclusions (60%) in SCAC were signi ficantly higher as compared to the rest of the SRCTs (P < .01 to < .00 01).