A 59-year-old man presented with a lesion of 2 years’ duration on his left temporal region. Although he had similar lesions, this one concerned him because it had 2 colors. The lesion was dome-shaped and had a diameter of 1cm; one half was yellowish-orange and the other one was violaceous. Dermoscopic examination showed 2 distinct components: an anterior half with converging yellowish lobules and a posterior half with vascular lacunes without interior structures separated by whitish tracts. A collision tumor composed of sebaceous hyperplasia and an acquired capillary angioma was suspected and the lesion was excised. The diagnosis was confirmed by histology (Fig. 1).

Figure 1

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The term collision tumor refers to the coexistence of 2 or more lesions in close proximity that appear to be a single lesion but have different histolopathological features and are separate entities. Collision tumors composed of melanocytic lesions (nevi, lentigines, and melanomas) and vascular lesions, seborreic keratoses, basal cell carcinomas, sebaceous carcinomas, and syringomas have been reported. Despite the high prevalence of sebaceous hyperplasia and acquired angiomas in the general population, it is surprising that we found no reports of a collision tumor comprising these 2 entities in the literature.