Sebaceus naevi: a clinicopathologic study.

OBJECTIVE: To analyse sebaceus naevus (SN) incidence, associated malignancies, and developmental defects in a retrospective study.

METHODS: We retrospectively analysed all cases of SN excised in our Department over a 20-year period. All cases of epidermal naevus syndrome (Schimmelpenning syndrome) associated with SN were recorded, as well as all patients with histological changes suggesting degeneration of the initial SN.

RESULT: A total 226 patients with SN were included in the study. Stage II was the most common (65%), and the parietal area was the most common location of SN (42%), with only 7% located in non-scalp areas. Syringocystadenoma papilliferum and trichoblastoma were the most common tumours arising on SN. We only found five patients with basal cell carcinoma arising on previous SN. Epidermal naevus syndrome associated with SN was diagnosed in 16 patients, and this was the most common neurocutaneous association.

CONCLUSION: The incidence of malignancy arising on SN was very low, indicating that prophylactic surgery of NS in children is not recommendable. Developmental defects should be investigated in order to evidence possible epidermal naevus syndrome associated with SN.