Tumours of the skin.

Tumours occur more frequently in the skin than in any other part of the body. Epithelial tumours are described under the following headings: basal cell tumour, squamous cell carcinoma, papilloma, sebaceous gland tumour, tumour of hepatoid glands, sweat gland tumour, mixed tumour of apocrine sweat glands, carcinoma of apocrine sweat glands, tumour of hair follicle, and intracutaneous cornifying epithelioma. Tumours of the melanogenic system are divided into benign melanoma and malignant melanoma, the latter being subdivided into the following types: epithelioid, spindle cell, epithelioid and spindle cell, dendritic, and whorled.