Histologic features of cutaneous sinus histiocytosis (Rosai‐Dorfman disease): study of cases both with and without systemic involvement

Abstract

Sinus histiocytosis with massive lymphadenopathy (Rosai‐Dorfnian disease) is a systemic proliferation of cells that resemble‐ the sinus histiocytes of lymph nodes. Whereas initial reports high‐lighted the often striking cervical adenopathy, more than 40% of patients have extranodal involvement. Cutaneous lesions are (Inmost common form of extranodal disease, but cases that present as cutaneous disease without lymph node involvement are rare. We examined biopsies from three patients with cutaneous lesions of sinus histocytosis, none of whom had detectable systemic involvement, and compared them to those of two patients whose lymph nodes were involved by the disease. The histology of skin lesions in all live cases showed dense nodular or diffuse infiltrates of “hisliocytes,” emperipolesis of lymphocytes, neutro‐phils, and plasma cells. “Histiocytes” were present in lumens of dilated lymphatics. At the peripheries of the lesions were lymphoid aggregates and thick‐walled vessels surrounded by plasma cells. Staining with anti‐S‐100 protein antibody showed marked cytoplasmic positively in the “hisliocytes” in each case. The only features that differed among the two groups were the presence ol pseudoepitheliomalous hyperplasia and infiltrates of eosinophils in one case in which the disease was limited to the skin. We believe that cutaneous sinus histiocytosis can be specifically diagnosed by skin biopsy. Because cutaneous sinus histiocytosis may be unfamiliar to general palhologists, dermatopathologists, and dermatologists, cases limited to the skin may be under‐recognized.