A healthy man in his 20s presented with a several-month history of asymptomatic, slightly erythematous cutaneous nodules, measuring 1.5 to 3.0 cm, over the calcanea (Figure , A). Physical examination revealed violaceous plaques, measuring 2 to 3 cm, on the extensor surface of the knees, bilaterally (Figure, B). Excisional biopsy specimens were obtained (Figure, C and D).Erythematous calcaneal nodules A Violaceous knee plaques B Calcaneal nodule specimen C Plaque specimen D Figure. A, Multiple asymptomatic erythematous nodules measuring 1.5 to 3.0 cm at presentation. B, Multiple violaceous plaques measuring 2 to 3 cm on the extensor surface of the knees. C, Excisional biopsy specimen of a calcaneal nodule (hematoxylin-eosin, original magnification ×20). D, Excisional biopsy specimen of a plaque (hematoxylin-eosin, original magnification ×20). WHAT IS YOUR DIAGNOSIS? A. Elastolytic granuloma B. Knee-located erythema elevatum diutinum (EED) with a calcaneal late-stage nodular component C. Epithelioid sarcoma D. Storiform collagenoma Clinical Review & Education JAMA Dermatology Clinicopathological Challenge