Malignant behaviour of primary intracranial Rosai Dorfman disease: a rare presentation of a benign disease.

ABSTRACT Background and purpose: The Rosai Dorfman disease (RDD) is a rare and usually benign lymphoproliferative disorder of unknown aetiology, typically characterized by head and neck lymphadenopathies. However, it may occasionally present with primary extra-nodal involvement including the central nervous system. We firstly described the potential malignant behaviour and fatal evolution of primary intracranial RDD. KeyWords: Rosai Dorfman disease; non-Langerhans histiocytosis; histiocytic proliferative disease; extra-nodal; cranial; malignant Illustrative case: A 69-year-old woman sought clinical attention for recurrent episodes of headache, fever and malaise associated with bilateral proptosis and left lower limb paresis. The brain MRI revealed bilateral retro-bulbar and fronto-parieto-occipital subdural lesions. The body CT did not show extracranial lesions. A right fronto-parietal craniotomy was performed and a subtotal resection was achieved. The histopathological diagnosis was consistent with RDD. Despite the patient was commenced on high-dose corticosteroids, she developed a worsening respiratory distress syndrome and a rapid systemic disease progression with liver and kidney failure. Given the poor general status, adjuvant medical and radiation therapies were not deemed safe and feasible and the patient died of multi-organ failure a month later. Conclusions: We documented an exceptional case of malignant primary intracranial RDD with malignant behaviour characterized by rapid systemic disease progression and poor prognosis. Although RDD with intracranial location has usually a benign and self-limiting course with good response to adjuvant treatments, it hides a malignant potential that may lead patients to death.