Abstract
Calcifying pseudoneoplasms of the neuraxis (CAPNONs) are extremely rare tumors that are frequently misdiagnosed and overlooked by clinicians. To date, only 40 intracranial lesions have been reported, and in all instances, they were found as a solitary calcified mass. To our knowledge, the current case report is the first to illustrate the development of multiple intraaxial CAPNONs and shed more light on the origin of these lesions.We discuss the case of a 67-year-old woman who presented with a six-year history of recurrent seizures. Magnetic resonance imaging revealed two similar heterogeneous intracranial masses in the ventral midbrain and left frontal white matter with indications of more aggressive behavior in the supratentorial tumor. The lesion was resected, and histopathological analysis showed tissue containing nodules of chondromyxoid material with a coarsely fibrillar matrix and focal alveolar pattern. Palisading cells were noted around the edges as well as dystrophic calcifications and osseous metaplasia, consistent with CAPNON. Interestingly, the patient had a previous history of multiple brain abscesses and a mycotic aneurysm. At her four-month follow-up visit, the patient remained seizure-free and there were no indications of residual tumor or recurrence.In contrast to previous reports, intracranial CAPNONs may manifest as multiple lesions and clinicians should include these tumors in the differential diagnosis of intra-axial calcified masses. The previous history of brain abscesses raises the suspicion of an abnormal proliferative process following an insult to the brain tissue as the underlying origin of these lesions.
Highlights
Calcifying pseudoneoplasms of the neuraxis (CAPNON), known as fibro-osseous lesions, are extremely rare tumors that can be located from the extremities to the central nervous system [1]
The first intracranial calcifying pseudoneoplasm was reported in 1978 by Rhodes and Davis when an unusual fibro-osseous component was identified in intracranial masses at autopsy and was described as an aberrant type of osseous metaplasia [4]
The current report is the first to demonstrate the development of multiple intracranial CAPNONs and sheds more light on the origin of these lesions
Summary
Calcifying pseudoneoplasms of the neuraxis (CAPNON), known as fibro-osseous lesions, are extremely rare tumors that can be located from the extremities to the central nervous system [1]. Magnetic resonance imaging (MRI) at the onset of seizures revealed multiple heterogeneous intracranial lesions located in the ventral midbrain and in the left frontal white matter. The lesion in the left frontal lobe showed moderate contrast enhancement as well as a mild adjacent hyperintense signal on T2-weighted images. T1-weighted images pre-contrast depicting two hypointense masses located in the ventral brainstem (A) and left frontal lobe (B). T1-weighted images postcontrast showing no contrast enhancement in the brainstem lesion (C) and heterogeneous enhancement on the left frontal lesion (D). Axial brain window images depicting hyperdense, calcified lesions in the brainstem (A) and left frontal lobe (B). An MRI scan performed six months later showed interval growth of the left frontal mass and an increased area of T2-weighted hyperintensity in the adjacent brain (Figure 3).
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