Septum Pellucidum Chronic Encapsulated Hematoma With Osseous Metaplasia Mimicking Recurrent Astrocytoma and Shunt-Related Foreign Body Granuloma

We present a very rare case of chronic encapsulated intracerebral hematoma involving the septum pellucidum and the foramen of Monro that by location radiological appearance, and clinical history was mimicking a recurrent astrocytoma or a shunt-related foreign body granuloma. A young adult underwent the resection of a juvenile pilocytic astrocytoma as a child, and with a mass encasing the tip of an old non-functioning ventricular catheter, the differential diagnosis of shunt-related foreign body granuloma versus recurrent low-grade glioma was raised. Although chronic encapsulated intracerebral hematomas have been reported in the literature, the anatomical location of the lesion in the presented case was unique, with radiological and history findings also posing a peculiar diagnostic challenge. Chronic encapsulated intracerebral hematomas are benign entities that may also be found to involve deep and midline supra-tentorial structures usually not prone to spontaneous intraparenchymal hemorrhages. When symptomatic, surgical resection of the hematoma can be both diagnostic and curative.