Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare benign tumor of uncertain etiology, arising in the craniospinal axis.
To date, about 60 cases have been reported in literature.
Paolini presented the case of a male 17-year-old who presented with new-onset seizures. MRIs revealed a 2 cm extra-axial solid-cystic mass, arising at the left temporo-occipital junction and abutting the dura with marked surrounding parenchymal vasogenic edema. The solid components demonstrated dense calcification and avid enhancement. Gross total surgical resection was performed. Histopathological examination revealed central regions showing characteristic features of CAPNON. Toward the periphery, the CAPNON was intimately associated with and sharply demarcated from a meningioma, which showed up to five mitoses per 10 high-power fields and had invasion into the adjacent brain parenchyma, warranting a WHO grade II designation. This is the first report of CAPNON arising in association with a meningioma. The coexistence of these two tumors raises the possibility of a reactive/dysplastic etiology for CAPNON 1).
Duchesne et al., present a case that had the peculiarity to occur in a pregnant woman. At 32 weeks of gestation, a 26-year-old woman was hospitalized to explore nocturnal epigastralgia. During the hospitalisation, the patient presented generalised seizures. As an eclampsia had been suspected, a caesarean delivery was performed. Post-operatively, the patient harboured memory disorders and neuro-imaging explorations were done. They showed an intracerebral calcified mass located in the left frontal lobe and surrounded by an oedema. A complete surgical resection was performed. Histological examination of the surgical specimen showed a calcified tissue containing a fibrillary or granular material. A dense and hyalinised eosinophilic material focally surrounded the calcifications and contained regular fusiform cells of fibroblastic type. Foci of lipomatous and osseous metaplasia were present. Immunohistochemical staining for EMA and STAT6 was negative. There was no associated meningioangiomatosis nor tumour proliferation. Forty-five months after surgery, the patient did not present any seizures and had no sequelae. CAPNON are rare lesions occurring at any age. Their location in the central nervous system is ubiquitous and they can be intra or extra axial. The treatment is surgical and the prognosis excellent. CAPNON must be recognized and distinguished from the other calcified lesions, tumoural or non-tumoural, to avoid an inadequate and potentially harmful treatment 2).