Sinonasal teratocarcinosarcoma is a rare and highly malignant tumor characterized by complex admixture of teratomatous andcarcinosarcomatous component. Here, we report a case of 72-year-old male presented with complaints of epistaxis, recurrent sinusitis,nasal stuffiness, and nasal blockade for past 5-6 months and his computed tomography report revealed as an inflammatory sinonasaldisease with polyposis. Histopathology examination showed fragments of upper respiratory mucosa admixed with fragments oftumor composed of benign and malignant counterparts of both epithelial and mesenchymal components in a variety of histologicpatterns. Also noted were the characteristic squamous epithelium with “fetal-type” clear cells, areas of necrosis, mitotic figure andsheets of undifferentiated blastemal like cells. Immunohistochemistry demonstrated positive staining for cytokeratin, epithelialmembrane antigen, vimentin, synaptophysin, S-100, chromogranin, and CD99. This polyimmunophenotypic characteristic anddiverse histological differentiation provided the basis for the diagnosis. Knowing its highly aggressive behavior, the patient shouldbe treated aggressively and followed up closely
