A 51-year-old man presented with a single, coin sized, nontender, erythematous nodule on the left thigh of a 2-week duration. There was a history of recurrence and spontaneous healing of similar asymptomatic eruptions five to six times over 20 years. A biopsy specimen showed a dense, wedge-shaped dermal infiltrate that was patchy and perivascular. The cellular infiltrate was polymorphous and consisted of large atypical cells, small lymphocytes, eosinophils and neutrophils. The large atypical cells were strongly CD30(Ki-1) positive.

We report a case of lymphomatoid papulosis unusually presenting as a single nodular eruption, in which the differential diagnosis between lymphomatoid papulosis and CD30(Ki-1)positive large cell lymphoma is exceedingly difficult.