Amyloidosis is a heterogeneous group of diseases with complex pathogenesis and may take on many forms and manifest in various organ systems. The pathophysiology invariably results in extracellular deposition of insoluble proteins with β-pleated sheet as their secondary structure. It is the β-pleated sheet of amyloidogenic proteins that allows histochemical identification under light microscopy [1, 2].
Amyloid deposition within the brain parenchyma can take on many forms, of which isolated amyloidomas are the least common [3, 4]. More common forms of cerebral amyloidosis include senile plaques seen in ageing and Alzheimer disease (AD) and sporadic cerebral amyloid angiopathy (CAA), while hereditary cerebral amyloid angiopathy and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephatlopathy (CADASIL) are rare. The histopathology and distribution of cerebral amyloid found in our case are not consistent with any of these known entities [1, 4–7].
A review of the literature reveals fewer than 30 reported cases [4, 8]. Of these, the majority of presenting cases were initially thought to be primary intracerebral neoplasms. The average age of presentation is in the fourth decade, with a slight female predominance given the very finite number of cases available for review. As may be expected, clinical presentation is protean with seizure, headache, and cognitive decline reported. Cerebral white matter is the most commonly involved area, with lesions most often being supratentorial . Typically, non-contrast CTs show hyperdensities that will enhance with contrast. MRI is more difficult to interpret due to variable results on imaging with some historically appearing hypointense, some isointense, and others hyperintense on T1 and T2 images .
The clinical course is thought to be benign, with no cases that were resected recurring. However, lesions that were biopsied without resection have shown growth . Little is known about long-term effects on such patients as there are few published reports with data going beyond five years . There are also limited data on surgical follow-up. The literature shows that most lesions were resected due to concerns of primary brain tumor. However, there have been no observed malignant transformations or other pathology related to amyloidomas that have been incompletely resected, therefore surgery is not necessary for the majority of patients with amyloidoma confirmed by biopsy . There is no reported role for diffusion tensor imaging.