Bone Marrow Infiltration By Nonhematopoetic Small Round Cell Tumors: A Clinicopathological Study From A Tertiary Care Centre In South India

Objectives: The objective of this study to comprehensively analyze bone marrow (BM) infiltration by nonhematological round cell tumors. Materials and Methods: A total of 206 diagnosed cases of small round blue cell tumors (excluding lymphomas) during a period of 21/2 years, referred for BM examination were included in the study. Clinical details were obtained from medical records. BM aspiration (BMA) and BM biopsies (BMBx) were performed under local anesthesia for staging workup. BMBx were studied for cellularity, presence of infiltration by round cells (nonhematopoietic), histologic patterns (island/nests and diffuse sheets), fibrosis, necrosis and other secondary changes. Inununohistochemistry panel was used depending on the morphology. Results: The cases included age range from 45 days to 25 years with a median age of 12 years. There was a male predominance with male:female 1.5:1. Among these, 37/206 cases (17.9%) were positive for BM involvement (BMI) on BMBx. Of these, 24 cases were neuroblastoma (64.8%), 9 cases Ewing's sarcoma/primitive neuroectodermal tumor (24.3%), and 4 Rhabdomyosarcoma (10.8). BMBx was done in all the 206 cases. Among these, 37/206 cases were positive for BMI on BMBx while 35/206 cases were positive on BM imprints and 33/206 cases were positive on BMA. Conclusion: Detection of metastasis in the BM has both therapeutic and prognostic significance. BMBx are complementary in the diagnosis of small round cell tumor.