Calcifying pseudoneoplasms of the neuraxis: Report on four cases and review of the literature.

OBJECTIVES: Calcifying pseudoneoplasms of the neuraxis (CAPNON) are rare lesions occurring anywhere in the central nervous system (CNS). Since their description, only 55 cases have been reported. We present the largest series reviewing their imaging features, histology and potential origins.

PATIENTS AND METHODS: four patients with histopathologically verified CAPNON are presented. Subsequently, we review all reports published with respect to study type, number of patients, clinical presentation, anatomical area (intracranial, spinal, or both), radiological features, therapy, histopathologic features, duration of follow-up, complications, and outcome. Moreover, current management of CNS CAPNON are discussed. Autopsy patients were excluded.

RESULTS: Four patients with histopathologically verified diagnosis of CAPNON are presented between 46-73 years-old. Three of them were located in the spinal cord (levels C3, D2, and L2) and one intracranial (left atrium). The spine ones were diagnosed due to radicular pain, paraparesis and numbness in lower limb, the intracranial because of intense headache. The differential diagnosis included cavernous malformation, in the case of the lumbar CAPNON this suspicion put back the surgery six months. All cases were surgically treated with complete resection. No recurrence showed at the 12-month follow-up. A total of retrospective 30 articles were selected: 10 case series (33.33%) and 20 reports of single cases (66.66%). The 30 articles and our additional cases added up to a total of 27 patients with spinal CAPNON and 32 patients with intracranial CAPNON. All patients were treated surgically. A follow-up, conducted in 48 patients, showed no signs of recurrence in 46 of the 48.

CONCLUSIONS: Calcifying pseudoneoplasms are rare benign lesions of yet unknown origin. They should be taken into consideration in the differential diagnosis of calcified lesions because an inaccurate diagnosis can result in potentially harmful and unnecessary therapies, as prognosis for these lesions is generally favorable.