muramidase and Histiocytosis--Sinus

Purely cutaneous Rosai-Dorfman disease is exceptional. The disease is characterized histologically by large, proliferating histiocytes exhibiting inflammatory cells within their cytoplasm (emperipolesis). We present here a case of purely cutaneous generalized disease in which the routine histopathology was suggestive of an inflammatory pseudotumor. Positivity for S-100 protein, alpha1-antitrypsin, alpha1-antichymotrypsin, lysozyme, Mac387 and CD68 proteins, and negativity for CD1a protein confirmed the diagnosis of Rosai-Dorfman disease. The rarity of this case lies in the presence of conspicuous inflammatory pseudotumor-like histopathologic changes, masking an otherwise typical sinus histiocytosis cell infiltrate. This unusual presentation of the disease requires a high index of suspicion by clinicians and pathologists.

Topics: Adult; alpha 1-Antichymotrypsin; alpha 1-Antitrypsin; Antigens, CD; Antigens, CD1; Antigens, Differentiation, Myelomonocytic; Diagnosis, Differential; Female; Granuloma, Plasma Cell; Histiocytosis, Sinus; Humans; Immunohistochemistry; Muramidase; S100 Proteins; Skin Diseases

Whereas Rosai-Dorfman disease (RDD) or sinus histiocytosis with massive lymphadenopathy is well described in lymph nodes and other organs, it is frequently not recognized in soft tissue. We studied the clinical and histologic features of 23 previously unreported soft tissue lesions from 17 patients (13 females, 4 males) who were 24 to 66 years of age (mean, 46 years). These lesions involved the extremities (12, 52%), trunk (6, 26%), head and neck (3, 13%), and the retroperitoneum (2, 9%). Associated lymph node involvement was present in four cases; most patients were asymptomatic. RDD of soft tissue had more subtle histologic features than its lymph node counterpart. Emperipolesis was less conspicuous and proliferating histiocytes were frequently spindled, associated with collagen deposition, and arranged in a vague storiform pattern with scattered lymphoplasmacytic aggregates. These features led to a variety of diagnoses, including benign inflammatory and fibrohistiocytic lesions (13 cases) as well as lymphoma and malignant fibrous histiocytoma (three cases). RDD was correctly diagnosed in only one case. Diagnosis was confirmed in 16 of 18 lesions by detection of S-100 protein and histiocytic markers KP1 (12 of 13) and lysozyme (eight of 11) in the characteristic histiocytes. Recognition that RDD of soft tissue occurs in an older patient population than does nodal RDD and that it mimics fibrous and inflammatory lesions of soft tissue is important.

Topics: Adipose Tissue; Adult; Aged; Connective Tissue; Connective Tissue Diseases; Female; Histiocytosis; Histiocytosis, Sinus; Humans; Immunohistochemistry; Lymphatic Diseases; Male; Middle Aged; Muramidase; S100 Proteins