An enigmatic combined tumour of oral malignant melanoma and oral squamous cell carcinoma - A rare case report.

Combined tumours are those composed of two benign tumours or a benign and malignant tumour or two malignant tumours occurring within the same tumour population. The incidence of combined tumours is very rare. Due to the rarity of these tumours, their biological behaviour remains unlashed. Incisional biopsy of a 48 years old female patient with single, diffuse tumour mass in the oral cavity showed combined tumour or collision tumour of malignant melanoma and squamous cell carcinoma. This was confirmed with immunohistochemistry study. The incidence of combined tumour of malignant melanoma and squamous cell carcinoma in oral cavity is extremely rare. To the best of our knowledge based on the previous literature records, this is the first case report of its kind where there is incidence in the human oral cavity.