Case 26 Female, 32 years. Multicoloured skin papule, shoulder.Show diagnosis & comments
Lentiginous compound naevus with seborrheic keratosis
NAEVI AND MELANOMAS ASSOCIATED WITH EPITHELIAL PROLIFERATIONS
Such combinations are not rare, and a large variety is encountered. Naevi may show epidermal changes of seborrheic keratosis, within or next to the naevus, but there may also be an association with a wide variety of other lesions, including basal cell carcinoma and adnexal tumours (especially trichoepithelioma). Epithelial tumours can be 'colonized' by presumably nonneoplastic reactive dendritic melanocytes (e.g., melanoacanthoma; Bednar tumour). A few distinctive lesions which cannot be 'dissected' as a combination of melanocytic and epithelial neoplasm but have features of their own, such as squamomelanocytic tumour, will be discussed elsewhere.