Brain Pathology Case of the Month - July 2004

Contributed by Lane H MB, PhD., Browne L MRCPI; Delanty N MD MRCP; O Neill S FRCP., Thornton J FRCR; Brett FM, MD FRCPath
Institute of Neurological Sciences, Royal College of Surgeons, Beaumont Hospital, Dublin 9, Ireland


A 40 year old man presented with severe frontal headaches, dry cough, impaired balance and dizziness for six weeks. On examination he had low-grade pyrexia and investigations revealed mild lymphopenia. Brain CT was normal and chest x-ray showed right hilar adenopathy with bilateral parenchymal infiltrates. A diagnosis of atypical pneumonia was made.

Four weeks later he represented with persistent headache, oscillopsia and unsteadiness of gait. On examination he was alert and orientated with minimal blurring of the disc margins, decreased heel shin testing and an inability to tandem. His CXR was unchanged; a high resolution CT thorax confirmed right hilar abnormalities (Fig 1). Infectious screen was negative. Brain MR post contrast revealed cerebellar enhancement and swelling with moderate tonsillar herniation (Fig 2); findings which precluded the performance of a lumbar puncture. He was commenced on high dose intravenous steroid therapy. Hilar node microscopy showed hyalinisation with occasional well formed epithelioid granulomata. No organisms were identified. A presumptive diagnosis of sarcoidosis was reached.

Despite an initial symptomatic improvement following commencement of steroid therapy, his headache persisted with variable intensity; neurological examination remained stable. Repeat MRI, eleven days later, showed reduced cerebellar enhancement and swelling with no change in the degree of tonsillar herniation. Over the next 24-36 hours he deteriorated with evidence of clinical herniation. Despite intravenous antibiotics and mannitol he suffered a respiratory arrest and was intubated. Repeat CT brain demonstrated severe cerebral oedema with evidence of coning. The following day he had fixed and dilated pupils and was declared brain dead after brain stem testing.


Autopsy examination of the brain revealed cerebral oedema with tonsillar herniation. The leptomeninges appeared dull and opaque with a gelatinous exudate over the surface of the brain, especially at the base. Microscopy revealed numerous organisms (Fig 3) that were highlighted by Grocott and PAS (Fig 4). No acid or alcohol fast bacilli could be demonstrated by Ziehl-Neelsen stain. There was minimal associated inflammatory reaction and no evidence of granuloma formation.

Examination of the thoracic cavity confirmed hilar adenopathy and sectioning the lungs revealed a fibrotic nodular appearance with one single necrotic lesion identified in the midzone of the right upper lobe. Microscopic examination of the hilar nodes revealed hyalinized non-caseating granulomata with no organisms or foreign material identified. Lung parenchyma was fibrotic with occasional non-caseating granulomata and Langerhan's giant cells . Organisms were identified only in the necrotic focus. Extra-pulmonary sarcoidosis was not identified.


International Society of Neuropathology