Case report of intracranial Rosai-Dorfman disease.

Rosai-Dorfman disease (RDD)-sinus histiocytosis with massive lymphadenopathy-represents a peculiar proliferation of histiocyte-like cells in patients. The condition was described by Rosai and Dorfman in 1969, after examining 4 cases, as an idiopathic histiocytic disorder. In 1972, they studied an additional 30 cases of patients with RDD. A histioproliferative disorder, RDD is characterized by bilateral, painless, cervical lymphadenopathy in 81% of patients. Fever, leukocytosis, elevated sedimentation rate, and polyclonal hypergammaglobulinemia may also be found. In 30% of patients, extranodal involvement is present and may include the skin, eye orbit, upper respiratory tract, or testes. Cases involving the central nervous system are rare and account for < 5% of patients with RDD. We report on a 78-year-old woman presenting with new-onset headache, dizziness, and imbalance, which had been present for a few weeks prior to admission. Magnetic resonance imaging of the brain showed 2 enhancing lesions within the right and left cerebellar hemispheres. Biopsy of the mass demonstrated a lymphohistiocytic infiltrate involving the cerebellum with foci of emperipolesis (phagocytosed lymphocytes). The adjacent cerebellum showed myelinated nerve fibers with reactive gliosis. A thorough work-up and histopathologic exam of the biopsied mass demonstrated lymphohistiocytic infiltrate with foci of emperipolesis (phagocytosed lymphocytes) consistent with RDD. Other differential considerations, such as primary or secondary neoplasms, infections, lymphoproliferative disorders, granulomatoses, Langerhans cell histiocytosis, and lymphocyte-rich meningioma were ruled out by additional histopathologic exam.