Objective:

To describe a unique case of Rosai-Dorfman Disease manifesting in central nervous system

Background:

Rosai-Dorfman Disease (RDD) is a rare type of histiocytic neoplasm that is driven by MAPK pathway mutations with highly efficacious treatments. RDD mainly manifests as a lymphoproliferative disorder in lymph nodes with extranodal involvement mostly in multiple intraabdominal organs. The central nervous system (CNS) spread is rare, thus CNS lesions may be misdiagnosed or not recognized as RDD.

Design/Methods:

N/A

Results:

Here, we present a case of a 50 years-old male with a 12 years of space-occupying, progressive pachymeningeal disease. The patient has been followed initially for a retroclival meningeal mass presumed to be a meningioma with only radiographic evidence due to high-risk biopsy location. He received fractionated radiotherapy to this location. During follow-up, due to diffuse spread pattern and no major response to radiotherapy, presumed diagnosis was changed to neurosarcoidosis. Meningeal spread led to papilledema and hearing impairment, requiring ventriculoperitoneal shunt and cochlear implant. He was then admitted to hospital for acute left hemiparesis and subacute altered mental status deemed to be due to new onset right frontal onset seizures. MRI showed diffuse pachymeningeal contrast enhancement and CT revealed perinephric mass. Given unclear diagnosis, biopsies of meninges and perinephric mass were pursued revealing histiocytic infiltrates with plasma cells and reactive T-cells. Immunohistochemistry staining showed positive CD163, S100, Factor XIIIA, Cyclin D1, CD3, and CD20 with negative ALK, BRAF and CD1a.

Conclusions:

RDD produces nodal and extranodal lesions with CNS manifestations mimicking meningioma and neurosarcoidosis. Our case illustrates importance of tissue diagnosis in RDD given CNS manifestations masquerade as other meningeal based lesions. It’s also important to note that repeat testing and broadening of differential with looking for other lesions is needed to clarify the diagnosis especially when the initial lesion does not behave as expected from the presumed diagnosis.