Multiple intracranial cavernomas with focal amyloid deposition - diagnostic pitfalls

Abstract

We report a case of a patient with multiple, intracranial superficial calcified tumorous lesions with focal amyloid deposition. On the basis of the first neuronavigated needle biopsy, the tumors were originally assessed as amyloidomas. Additional data was obtained from a second biopsy and supplementary neuroimaging information and the tumors were diagnosed as of vascular origin, probably cavernomas. The report exemplifies how only one diagnostic tool may sometimes be misleading in establishing a final diagnosis. The additional imaging may thoroughly enhance, supplement and improve the diagnostic process.

Figure 1.. Neuroradiological feature of multiple cavernomas. The axial CT scan shows hyperdense expansive multifocal leptomeningial lesions. The signal intensity arises from intralesional calcium deposits (A). T1 weighted MRI shows two more superficial lesions. The intensity of signal is uneven and only focally hyperintensive (B). The T2 weighted MRI demonstrates the same lesions as in T1 and some smaller lesions scattered inside deep brain tissue, all of them showing hyperintensive but uneven signal (C). The T2* MRI shows even more small lesions in the deep brain tissue, giving a hypointensive signal. The larger superficial tumours are unevenly hypointensive and encircled with a thin hypointensive rim that corresponds to hemosiderin deposits located in and around the lesions (arrows) (D).

Figure 2.. Two biopsies of the largest occipital tumor. A: The first needle biopsy, van Gisson: Amorphous, almost acellular, eosinophilic tissue without obvious vessel formation. B: Two foci of congophilic material (arrows) with a characteristic green birefringence under the polarised microscope (arrows) in C. The second biopsy of the same tumor, van Gisson: Several blood-filled vascular channels (asterisk) separated by fibrotic hyalinised tissue (D).