Introduction: Calcifying pseudoneoplasms of the neuraxis (CAPNON) are rare lesions occurring anywhere in the central nervous system (CNS). Since their description, only 45 cases have been reported. We present the largest series reviewing their imaging features, histology and potential origins.
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.
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 D2, C3 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 21 retrospective articles were identified and selected for review: 7 case series (33.3 %) and 14 reports of single cases (66.6 %). The 21 articles and our additional cases added up to a total of 22 patients with spinal CAPNON and 24 patients with intracranial CAPNON. All patients were treated surgically. A follow-up, provided in 34 patients, showed no signs of recurrence in 32 of 34 patients .
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.
Patient Care: CAPNON should be considered in the differential diagnosis of calcified CNS tumors. Radiological suspicion and histopathologic diagnosis are extremely important in the characterization of these lesions in order to direct the course of appropriate management. An inaccurate diagnosis of a malignant tumor can result in potentially harmful and unnecessary therapies, as prognosis for these lesions is generally favorable.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of CAPNON and identify them, 2) Discuss, in small groups and notice any case under diagnosed in their unit 3) Identify an effective treatment avoiding any complication of an aggressive treatment "
References: 1: Lyapichev K, Bregy A, Shah AH, Shah K, Desai MB, Petito C, Komotar RJ.
Occipital calcified pseudoneoplasms of the neuraxis (CAPNON): understanding a
rare pathology. BMJ Case Rep. 2014 Dec 5;2014. pii: bcr2014206855. doi:
2: Stienen MN, Abdulazim A, Gautschi OP, Schneiderhan TM, Hildebrandt G, Lücke S.
Calcifying pseudoneoplasms of the neuraxis (CAPNON): clinical features and
therapeutic options. Acta Neurochir (Wien). 2013 Jan;155(1):9-17. doi:
10.1007/s00701-012-1502-2. Epub 2012 Oct 3. Review.
3: Mohapatra I, Manish R, Mahadevan A, Prasad C, Sampath S, Shankar SK.
Calcifying pseudoneoplasm (fibro osseous lesion) of neuraxis (CAPNON) - a case
report. Clin Neuropathol. 2010 Jul-Aug;29(4):223-6.
4: Aiken AH, Akgun H, Tihan T, Barbaro N, Glastonbury C. Calcifying
pseudoneoplasms of the neuraxis: CT, MR imaging, and histologic features. AJNR Am
J Neuroradiol. 2009 Jun;30(6):1256-60. doi: 10.3174/ajnr.A1505. Epub 2009 Apr 15.