Benign scalp lump as an unusual presentation of extranodal Rosai-Dorfman Disease

RDD is a rare condition and isolated CNS RDD is even less common. Benign scalp lumps have a myriad of differential diagnoses, but RDD should be a consideration in the presence of preexisting RDD lesions at other sites given its potential to progress and result in morbidity. It is imperative to be aware that symptoms may be especially deceiving as the absence of lymphadenopathy may point away from RDD as the diagnosis.