Characterizing leptomeningeal enhancement patterns may help guiding further investigations to reach accurate diagnoses. 

Leptomeningeal enhancement (LME) on contrasted MRI is an indicator of blood brain barrier compromise and can be caused a variety of neurological and systemic disorders including neoplastic and inflammatory conditions as well as infections.

This case series presents six patients chosen using convenience sampling that had a variety of diagnoses including spindle cell neoplasm, diffuse large B-cell lymphoma (DLBCL), metastatic gastric adenocarcinoma, tuberculosis, HIV meningitis, and possible neurosarcoidosis. Clinical presentations, laboratory investigations, imaging characteristics, and outcomes were analyzed and presented.

LME patterns varied by etiology. Glioblastoma demonstrated diffuse nodular thickening of the cauda equina with cranial nerve involvement. DLBCL showed extensive thick LME involving the distal conus and lumbosacral nerve roots. Gastric adenocarcinoma metastatic lesions produced diffuse, thick LME of the posterior fossa, cerebellar folia, brainstem, and basal cisterns with hydrocephalus. Tuberculosis exhibited localized LME in the left insular fissure with parenchymal enhancing foci. HIV meningitis revealed confluent diffuse LME, more extensive than typical viral meningitis. Possible neurosarcoidosis showed diffuse smooth-to-nodular LME of the lower thoracic cord, conus medullaris, and suprasellar cistern.

LME patterns on MRI may demonstrate etiology-specific characteristics that may guide diagnostic evaluation. Some cases don’t follow common patterns and can be challenging to diagnose.