Generalized eruptive histiocytosis.

Abstract

The histiocytic disorders can be broadly categorized into histiocytosis X (Langerhans cell-derived) and non-X types. There are several variants of non-X histiocytoses that tend to occur in a generalized distribution on the body; these include xanthoma disseminatum, generalized eruptive histiocytosis (GEH), progressive nodular histiocytosis, and multicentric reticulohistiocytosis. Clinical and pathologic correlation are required for differentiating among these 4 disorders. We report a case of a middle-aged man in whom small, scattered, symmetrical lesions on the trunk and proximal extremities developed that, after correlating with biopsy specimen and laboratory results, were best classified as a non-X histiocytosis with features of GEH. GEH is a rare generalized non-X histiocytosis that occurs mainly in adults. It is characterized by multiple, scattered, symmetric lesions on the trunk and proximal extremities that are benign in nature and tend to resolve spontaneously. Recent literature has suggested that GEH may be a part of a continuous spectrum of non-X histiocytic disorders.