[Amyloidoma of the central nervous system: CT and MR aspects]

To report a case of tumor like amyloïd formation (amyloidoma) of the brain with etiologic discussion.

and Methods. A 46-year-old female had a 7 year history of epilepsy. CT scan and MRI revealed two enhancing lesions in the white matter of the right temporal and frontal lobes.

Stereotactic biopsy examination showed large amyloid deposits surrounded by sparsely scattered lymphocytes, few matures plasma cells, macrophages and rare foreign body type giant cells. The congophilic amyloid was found in the interstitium as well as within the walls of blood vessels with close connection to the choroid plexus. No significant abnormalities were noted on routine laboratory studies.

Unlike all other types of amyloid, AL amyloid can produce both systemic amyloidosis and solitary amyloidoma. Amyloidomas are rare and usually found in the lung, skin, lower urinary tract. The location in the brain is extremely rare, with only 16 cases reported in the literature. All this cases as well as our example in the current study to some extent involved deep white matter. The association with choroid plexus is possible. The relatively indolent course of this amyloidomas is noted. Our study showed a presence of monotypic lambda producing plasma cells. Thus this lesion could be the result of monoclonal B cell neoplasm capable of terminal differentiation and the existence of AL amyloid producing low grade B lymphomas of the brain could be discussed.