Histochemical study of generalized eruptive histiocytoma (GEH) showed large amounts of hydrolytic enzymes, including nonspecific esterase, aminopeptidase, nucleoside triphosphatase, and acid phosphatase, as well as the oxidative enzymes, succinic dehydrogenase and dephosphopyridine nucleotide diaphorase, in moderate amounts. Succinic dehydrogenase was evenly distributed throughout the tumor cells with diphosphopyridine nucleotide diaphorase only in localized foci. The enzymatic signature of GEH is similar to that in histiocytes of normal skin as well as that in other histiocytic disorders. The enzymes seem characteristic of the histiocytic cells themselves and may not be dependent on cellular change occurring in inflammation and active phagocytosis. Ultrastructural observations supported the light microscopic impression of a cellular proliferative lesion in which significant phagocytosis was not evident.
Muller SA, Wolff K, Winkelmann RK. Generalized Eruptive HistiocytomaEnzyme Histochemistry and Electron Microscopy. Arch Dermatol. 1967;96(1):11-17. doi:10.1001/archderm.1967.01610010017002