Rhabdomyosarcoma - An epidemiological and histopathologic study of 277 cases from a major tertiary care center in Karachi, Pakistan

Aim: To present the epidemiologic data (age, gender, size etc) and histopathologic and immunohistochemical features of cases of rhabdomyosarcoma (RMS) reported in our department. Settings: Section of Histopathology, Department of Pathology and Microbiology, Aga Khan University Hospital, Karachi, Pakistan. Duration: All cases of RMS diagnosed between January 1, 2003 and December 31, 2012 were included in the study. Results: A total of 277 cases were included. Embryonal rhabdomyosarcoma (ERMS) was by far the dominant histologic type (87.4%) followed by alveolar type (ARMS)(9.4%). ERMS was much more common in males (64.0%)and over 65% of cases occurred in the first decade of life (over 90% in the first two decades). Head and neck region was commonest site for ERMS (46.7%), followed by the genitourinary system (16.1%). Over 65% cases of ARMS occurred in the extremities. Over 80% cases of ARMS occurred in the first 3 decades of life. Immunohistochemical staining for Desmin and MyoD1 was positive in 96.7% and 85.4% respectively. Conclusions: The epidemiologic data and microscopic findings in our patients are similar to international published data on rhabdomyosarcoma.