Solitary orange papule on the back of a middle-aged man

A 51-year-old man with a history of recurrent primary cutaneous marginal zone lymphoma involving his back returned for a follow-up visit at our cutaneous lymphoma clinic. He complained of a several-month history of a new asymptomatic papule on the mid-thoracic back. He denied fevers, chills, night sweats or fatigue. Clinical examination identified a 3 to 4 mm red to orange-colored papule on the middle back (Figure 1A). Dermoscopic examination of the lesion revealed an erythematous border encircling an orange-yellow area with white linear streaks and few dotted vessels (Figure 1B). A biopsy and histopathological examination performed to exclude recurrence of skin lymphoma demonstrated a nodular dermal infiltrate of histiocytes with vacuolated foamy xanthomatous cytoplasm and Touton-type multinucleated giant cells (Figure 2). The histiocytes stained positively for CD68 and were negative for Sox10.