An unusual association of calcifying pseudoneoplasm of the neuraxis with interhemispheric lipoma and agenesis of corpus callosum: case report

Abstract

Calcifying pseudoneoplasms of the neuraxis (CAPNON) are rare tumours that can occur anywhere in the central nervous system. The aetiology and natural history of these lesions is unclear. We report an unusual case of intraparenchymal CAPNON that occurred in association with interhemispheric lipoma and agenesis of the corpus callosum. The patient was a 47-year-old woman with known congenital absence of corpus callosum who presented with a progressive 6-month history of worsening headache, ataxic gait, blurred vision and poor memory. Magnetic resonance imaging (MRI) revealed complete agenesis of the corpus callosum with associated interhemispheric lipoma and an unusual calcified intra-parenchymal mass, largely hypointense on T2 with intermediate signal centrally on T1, surrounded by an ill-defined vasogenic oedema. Histologically, the first lesion was confirmed as lipoma. The second lesion consisted of multiple nodules of chondromyxoid matrix partially rimmed by a single layer of palisading spindled to epithelioid cells and focal osseous metaplasia including mature lamellar bone. The final diagnosis was CAPNON associated with interhemispheric lipoma and agenesis of the corpus callosum. To our knowledge, this is the first reported association between these uncommon lesions. CAPNON have relatively non-specific radiological features with a broad differential diagnosis, but have distinctive histological features. Accurate identification of CAP-NON will help avoid misdiagnoses and unnecessary therapeutic procedures since wide local excision is curative.