gms | German Medical Science

Objective: Scattered cerebral amyloid depositions are considered to be part of a complex group of protein folding disorders usually associated with progressive neurodegenerative entities that include, among many others, Congophilic angiopathy and Alzheimer's disease. On the other hand, localized amyloid masses in the brain usually indicate systemic amyloidosis whose prognosis is dismal. In rare instances, condensed amyloid accumulations can be confined to the brain without a systemic manifestation. This is referred to as amyloidoma, and there are less than 20 cases reported so far.

Methods: Case presentation: A 50-year-old woman presented with her first generalized seizure. Neurological and neuropsychological findings were normal. Magnetic resonance imaging (MRI) of the brain showed a right temporal mass enclosing neo- and allocortical (limbic) regions with reticulated contrast enhancement and focal calcifications, suggesting a high-grade glioma. Intraoperatively, a firm, hypovascularized and poorly demarcated tumor was removed subtotally. Its histopathologic examination showed neuroectodermal tissue with a distinct sclerosis of the vessel walls, a marked perivascular gliosis, lymphocytic infiltrations and accumulations of amorphous eosinophilic nodules staining Congo red, which indicate amyloid deposits. Immunohistochemistry showed lambda chain predominance. There was no evidence for systemic amyloidosis in the further diagnostic workup.

Conclusions: Primary brain amyloidoma (PBA) is a rare non-neoplastic cerebral mass lesion that can mimick an infiltrating tumor. Although seizures are the most common presenting symptom, progressive cognitive decline was also a frequent finding in the literature cases suggesting PBA as a particular neurodegenerative entity thus questioning the benign natural history assumed by some authors. The histopathological finding of condensed cerebral amyloid accumulations should be followed by a thorough screening of the patients for systemic amyloidosis or hematologic diseases. In cases confirmed by stereotactic biopsy, neurosurgical resection of PBA should be considered as the lesions are highly epileptogenic and might eventually expand.