[Evolution of sebaceous hamartoma: prospective pathologic study illustrated with a voluminous ear location]

After an exeresis of a sebaceous hamartoma of retroauricular area, histologic examination showed a trichoblastoma mimicking a basal cell carcinoma. So we realized a retrospective study with histologic examination of 24 cases of basal cell carcinoma after hamartoma. On 24 cases, 19 were not basal cell carcinoma, but trichoblastoma. So the study goes in the same direction of the world literature: hamartoma have a minimal risk of basal cell carcinoma transformation. Exeresis is indicated because of the risk of evolution to a hypertrophic tumour.