A case of oral multiple primary cancer including Spindle Cell Carcinoma.

Spindle Cell Carcinoma (SPCC) is a relatively rare tumour that is classified as a subtype of squamous cell carcinoma (SCC). Histologically, SPCC is composed of a SCC region and epithelium-derived spindle cells with mesenchymal differentiation. We encountered an interesting case of multiple cancer including SPCC. A histopathologically atypical papillary lesion was found 13 years before our initial examination. Multiple verrucous leukoplakia later developed in the oral mucosa, for which an oral vitamin A derivative (a retinoid) was intermittently administered. Multiple cancer including SPCC subsequently developed in the lower gingiva. We investigated the case histologically and immunohistologically based on the concept of field cancerization.