A Wrong Turn at the Angle (slideshow)

The surgical specimen revealed numerous giant cells scattered within abundant chronic inflammation and fibrosis (Slides 5-11). Stains for organisms were negative. The original brain MRI was reinterpreted as showing that the medullary mass arose from the pia. Subtle FLAIR signal abnormalities were identified in the adjacent medulla and pons (Slide 12). These abnormalities were, in retrospect, considered more consistent with inflammation than meningioma. Total spine imaging revealed cervical, thoracic, and lumbosacral intradural/extramedullary lesions (Slide 13). Imaging of the chest/abdomen/pelvis showed mediastinal and hilar lymphadenopathy (Slides 14, 15). Bronchoscopic biopsies of mediastinal lymph nodes showed pathologic abnormalities similar to those of the brain lesion, consistent with sarcoidosis (Slides 16, 17). Treatment with corticosteroids, mycophenolate, and infliximab resolved the spine abnormalities but did not improve the patient's neurologic status, which has remained stable for 2 years (Slide 18). She cannot walk unassisted. The imaging diagnosis of meningioma was reasonable for the CPA mass, and metastasis could also be considered (1,2,3). The T2 hypointensity of the mass made meningioma less likely in hindsight. When the pial and parenchymal signal abnormalities are considered along with the CPA mass, though, the diagnosis is much more likely to be inflammation, such as sarcoidosis. That diagnosis would trigger an imaging evaluation of the chest/abdomen/pelvis and spine, which in our case disclosed the lesions of sarcoidosis. In retrospect, the imaging characteristics of the large CPA mass (T1 isointensity, T2 hypointensity, and intense enhancement) were entirely consistent with sarcoidosis (1,2). Symptomatic intracranial involvement in sarcoidosis occurs in about 5 percent of cases, but imaging and post-mortem involvement is higher (1,2,4). Leptomeningeal disease is more common than dural or parenchymal disease (1,4,5).