A 47-year-old Hispanic man first noticed an asymptomatic growth on the extensor surface of his left forearm 5 years before presentation. He subsequently had similar growths on his hands and forearms. His medical history was notable for keratinizing squamous cell carcinoma of the bladder 4 years earlier. The tumor was completely resected, and there was no pathologic evidence of metastasis. Generally, the patient was in good health, and a review of systems revealed no abnormalities. His occupational history included chicken processing and work with cement, paint, and tobacco. He had no known exposure to cutting oils or tar.
Todd MM, Ammirati CT, Billingsley EM, Miller JJ, Helm KF. Multiple Hyperkeratotic Nodules on the Arms—Quiz Case. Arch Dermatol. 2003;139(10):1363-1368. doi:10.1001/archderm.139.10.1363-a