IgG4-Related Hypertrophic Pachymeningitis at the Falx Cerebrii with Brain Parenchymal Invasion: A Case Report.

Abstract

Hypertrophic pachymeningitis has been described as a manifestation of a number of conditions, like infection and neoplasms such as dural carcinomatosis or lymphomas. IgG4-related hypertrophic pachymeningitis is a new entity identified during the past decade and most reports described pachymeningeal involvement only. We present a 58-year-old woman with isolated IgG4 hypertrophic pachymeningitis at the falx cerebrii that exhibited cerebral parenchymal invasion. She initially presented with left lower limb weakness. Magnetic resonance imaging of brain showed a contrast enhancing lesion located at the falx and that eroded into the right frontal lobe. Subsequent excisional biopsy confirmed the lesion with brain parenchyma invasion. The pathologic diagnosis was IgG4-related disease. She had no evidence of extracranial involvement. Overall, this is an uncommon condition that may exhibit parenchymal invasion. Surgical biopsy would serve to establish a definitive diagnosis, and prompt comprehensive management of what is essentially a systemic and treatable condition.