Objective: To present a case of anterior abdominal wall mass in a young adult male with histopathologic diagnosis of carcinosarcoma. Design: Case Report Setting: Tertiary Hospital in Davao City, Philippines This is a case of a 22-year-old male who presented with progressive knee pain and an incidental fi nding of anterior abdominal wall mass with spinal cord compression symptoms. He underwent posterior decompression and screw fi xation of vertebra, and excision of anterior abdominal wall mass. Microscopic fi ndings of tissue specimens revealed malignant small round cell tumor. Immunohistochemical stain done on abdominal wall mass was strongly positive for cytokeratin and vimentin, negative for leukocyte common antigen (LCA), non-specifi c esterase (NSE), desmin, and chromogranin A. The stained cells were distinctive and separated but admixed which was more compatible with carcinosarcoma. The patient however succumbed to sepsis prior to further management. This paper serves to report a highly aggressive tumor in a previously- well young man whose histopathologic diagnosis with basic microscopy yielded diverse differentials. Further workup with immunohistochemistry came up with a fi nal diagnosis of carcinosarcoma in the anterior abdominal wall metastatic to bone, spine, and soft tissue in the head.