Eosinophilic histiocytosis. A subset of lymphomatoid papulosis.

A 43-year-old male with a 23-year history of small-plaque-type parapsoriasis developed a chronic recurrent self-healing papulonodular and tumoral cutaneous eruption. The microscopic findings were consistent with eosinophilic histiocytosis. Immunohistochemical and ultrastructural studies revealed a population of T lymphocytes, eosinophils and monocyte-macrophage cells in the dermal infiltrate. These findings confirm the similarities between eosinophilic histiocytosis and lymphomatoid papulosis suggesting that the former may be a clinicopathologic variant of the latter.