Mesenchyme Meets Epithelium: Immunohistochemical Challenges in Sarcomatoid Carcinoma

Sarcomatoid carcinomas are biphasic tumors proven to be monoclonal dedifferentiated forms of conventional Squamous Cell Carcinomas which is characterized by a dysplastic epithelial component and a stromal element with invasive fusiform or spindle-shaped cells. The clinical and histopathologic characteristics make it very difficult to distinguish Sarcomatoid Carcinoma from conventional Squamous cell Carcinoma .The present case depicts a 74 year old male patient with a chief complaint of a large, irregular, multilobulated ,exophytic soft tissue growth, having brownish black appearence involving bilateral maxillary alveolar ridge and buccal sulcus region since 1month . Incisional biopsy was performed – soft tissue was processed and finally the paraffin block was sent for immunohistochemical analysis. The dilemma in diagnosis was resolved by microscopic observation of invading atypical epithelial cells into the stroma and the epithelial as well as mesenchymal lineage was confirmed through immunopositivity for Vimentin, CK7 & EMA.