Rosai-Dorfman's illness, also denominated sinus histiocytosis with massive lymphadenopathy is considered benign entity of unknown etiology; although it is believed it may be due to alterations of immune system. It was described in 1969 by Rosai and Dorfman and there are nearly 500 cases worldwide reported. The most frequent clinical manifestation is massive lymph node enlargement, mainly cervical, but almost in the fifth percent of cases any lymph node may be affected. Diagnosis is pathological, without treatment of choice, evolution is often spontaneous resolution. In extraganglionar compromise, illness may be progressive and fatal. A45 year-old woman with cervical and nasal lymphadenopathy and fever is presented. Biopsy report: histiocytosis with emperipolesis phenomenon and immunohistochemical markers S-100, CD48, and CD45, positives. Encountering total T lymphopenia, mainly CD4+ diminished relationship CD4/CD8 and polyclonal gammopathy. Relevant in this case, clinical presentation multiple lymph nodes, distinct of other reported in our country whose presentation was mainly cutaneous plus association among Rosai-Dorfman with immunological changes and good clinical response to immunomodulator treatment, not previously seen, as in this patient.