Extraocular sebaceous carcinoma mimicking benign sebaceous cyst.

Extraocular sebaceous carcinoma (SC) is an exceptionally rare neoplasm and has been confused in the past with basal cell carcinoma showing sebaceous differentiation. However, in contrast to the latter tumour, SC can be an aggressive cancer. We describe the case of a 55-year-old man with a 3-year history of a 5 × 2 cm lesion on the posterior thoracic wall. It had increased in size during this period but was otherwise asymptomatic. There was no significant past medical history or lymphadenopathy. Nor was there a family history of malignancy. The lesion was totally excised. The histopathological report revealed SC. As this neoplasm may be associated with Muir-Torre syndrome, the patient was screened for underlying internal neoplasia. All haematological, biochemical and tumour markers, imaging and endoscopic examinations were normal. Since SC may appear before the development of internal malignancy, our patient was scheduled for follow-up visits every 3 months.