This otherwise healthy young woman presented with papules and nodules on her forearms, wrists, and hands. Erythema elevatum diutinum is extremely rare and its etiology unknown, although there have been reports following viral illness, injections, and systemic disease. There are two stages of an individual lesion. Early findings are that of leukocytoclastic vasculitis. Later, as the lesion organizes, it becomes large and fibrotic, almost keloidal. Histologically, these can be mistaken for tumors, including sclerotic fibromas. However, there is an inflammatory component and sometimes vasculitis in the lesion, both unusual for tumors. It probably is more akin to a nodular fasciitis.
This biopsy of acral skin shows a tumorous mass, confined to the dermis. The mass consists of tightly bundled spindle cells. It is well-demarcated but unencapsulated.