Rosai-Dorfman disease with extranodal manifestation in the head.

The term sinus histiocytosis with massive lymphadenopathy (SHML) was introduced by Rosai and Dorfman in 1969. Although SHML was initially described as low-pain cervical lymphadenopathy accompanied by fever, leukocytosis, an increased erythrocyte sedimentation rate, and hypergammaglobulinemia, extranodal involvement is observed in 25 to 40% of cases. This pathology is very rare and involvement of the nasal fossae and paranasal sinuses is exceptional. We present two atypical cases of extranodal involvement exclusively confined to the head and review the literature. The first case showed a dramatic involvement of facial skin and muscles, orbit, and paranasal sinuses. In the second case, the disease was limited to the nasal fossae. Both cases showed exclusive extranodal involvement limited to the head region. In the absence of lymphadenopathy, diagnosing Rosai-Dorfman disease is difficult because of the lack of the most typical manifestation of the disease.