muramidase and Histiocytosis--Non-Langerhans-Cell

The clinicopathological and immunohistochemical features of four patients with systemic multicentric reticulohistiocytosis (MR) were compared with five cases of solitary and one case of multiple reticulohistiocytoma (RH), which were confined to the skin only. The MR cases mostly affected the limbs of older women, while RH affected young male adults without preference to site. Characteristically, both entities consisted of oncocytic mononuclear histiocytes (with granular eosinophilic cytoplasm similar to oncocytic thyroid cells) and multinucleated histiocytes with a ground-glass appearance, which appeared to be much larger (> 200 microns) and bizarre in cases of RH compared with cases of MR (50-100 microns). In RH a variable number of vacuolated, spindle-shaped, and xanthomatized mononuclear histiocytes were also present. Immunohistochemical profiles showed positivity of mononuclear histiocytes with HHF35, factor XIIIa, and LN3 (HLA-DR), with a variable number of multinucleated histiocytes in RH showing binding with peanut agglutinin. In mono- and multinucleated histiocytes in both entities macrophage markers KP1 (CD68), KiM1P, HAM56, lysozyme, and alpha 1-antitrypsin were positive. However, macrophage markers MAC387 (L1 antigen) and Leu-M1 (CD15) were negative. Vimentin was universally positive in both conditions, with all other markers (S100, desmin, smooth muscle-specific actin, and QBEnd 10 [CD34]) negative. This study shows that histology supplemented by immunocytochemistry delineates MR from RH and immunohistochemical profiles indicate a cell lineage relationship between RH and adult xanthogranuloma.

Topics: Adolescent; Adult; alpha 1-Antitrypsin; Cell Nucleus; Child; Child, Preschool; Cytoplasm; Female; Granuloma; Histiocytes; Histiocytosis, Langerhans-Cell; Histiocytosis, Non-Langerhans-Cell; HLA-DR Antigens; Humans; Immunophenotyping; Macrophages; Male; Middle Aged; Muramidase; Skin Diseases; Transglutaminases; Vimentin; Xanthomatosis

Reticulohistiocytoma is a rare, benign histiocytic lesion usually occurring as an isolated skin nodule or as part of a systemic disorder known as "multicentric reticulohistiocytosis." The clinical and histopathologic findings of two women who presented with a single, painless mass localized to the cornea and limbus without skin lesions or systemic disease are reported. Histopathologically, the lesions were composed predominantly of large mononuclear and a few multinucleated cells with finely granular, "ground-glass" cytoplasm and large nuclei with prominent nucleoli. Immunohistochemical and electron microscopic studies conformed the histiocytic nature of these cells. Reticulohistiocytoma should be included in the differential diagnosis of epibulbar benign histiocytic lesions.

Topics: Adult; Chymotrypsin; Corneal Diseases; Female; Histiocytosis, Non-Langerhans-Cell; Humans; Immunoenzyme Techniques; Muramidase; Phosphopyruvate Hydratase; S100 Proteins; Scleral Diseases; Visual Acuity