Acquired generalized hypertrichosis due to diazoxide.

neous biopsies, yielding 69 collision tumors. Cascajo and colleagues found 54 collision tumors of malignant cutaneous neoplasms associated with seborrheic keratoses in 85,000 biopsies. The most common combinations found by Boyd and Rapini included basal cell carcinoma and nevus (14), basal cell carcinoma and seborrheic keratosis (8), nevus and seborrheic keratosis (14), actinic keratosis and nevus (7), and basal cell carcinoma and neurofibroma (4). Another commonly described association is that of melanocytic nevus with desmoplastic trichoepithelioma. Our patient had a compound tumor of congenital nevus and dermatofibroma. As far as we know, this is the first reported case of such a combination. Furthermore this tumor clinically and dermoscopically mimicked malignant melanoma. Although in some cases dermoscopy can help with collision tumor diagnosis, this was not the case. In fact, according to Giorgi and colleagues cutaneous collision tumors are extremely difficult to diagnose preoperatively, even with the help of dermoscopy, in particular when one of the lesions is melanocytic. The presence of a pigment network, the pathognomonic sign of the melanocytic lesion, allows dermatologists to use dermoscopic algorithms, which in this case ended up in the wrong preoperative diagnosis of a malignant lesion. References