Derm Dx: Cystic nodule on a man's forearm

A 58-year-old man requests removal of a lesion on his left forearm. The growth was noted more than 2 years ago and has enlarged gradually to its present size. He denies similar lesions elsewhere. Examination reveals a 1.2-cm whitish firm cystic nodule with no evidence of a dilated pore. No tenderness is elicited on palpation.