Dermoscopy is useful for the recognition of benign-malignant compound tumours

The association of two different neoplasms in the same lesion is uncommon and has been reported as collision or compound tumours in the medical literature. In cases where a malignant neoplasm exists in association with a benign lesion it is important to make an accurate diagnosis in order to treat the lesions correctly. Dermoscopy is an in vivo, noninvasive technique that improves the clinical accuracy in diagnosing melanoma and other pigmented skin lesions. We describe the dermoscopic characteristics of various collision or compound tumours that were composed of benign and malignant neoplasms: two cases of seborrhoeic keratosis associated with basal cell carcinoma, two cases of melanocytic naevus and basal cell carcinoma and one case of dermatofibroma associated with basal cell carcinoma. We conclude that dermoscopy is a useful tool for improving the recognition of these kinds of tumours.