title: Spontaneous regression of septum pellucidum/forniceal pilocytic astrocytomas--possible role of Cannabis inhalation.
abstract: BACKGROUND
  Spontaneous regression of pilocytic astrocytoma after incomplete resection is well recognized, especially for cerebellar and optic pathway tumors, and tumors associated with Neurofibromatosis type-1 (NF1). The purpose of this report is to document spontaneous regression of pilocytic astrocytomas of the septum pellucidum and to discuss the possible role of cannabis in promoting regression.
  
  
  METHODS
  We report two children with septum pellucidum/forniceal pilocytic astrocytoma (PA) tumors in the absence of NF-1, who underwent craniotomy and subtotal excision, leaving behind a small residual in each case. During Magnetic Resonance Imaging (MRI) surveillance in the first three years, one case was dormant and the other showed slight increase in size, followed by clear regression of both residual tumors over the following 3-year period. Neither patient received any conventional adjuvant treatment. The tumors regressed over the same period of time that cannabis was consumed via inhalation, raising the possibility that the cannabis played a role in the tumor regression.
  
  
  CONCLUSIONS
  We advise caution against instituting adjuvant therapy or further aggressive surgery for small residual PAs, especially in eloquent locations, even if there appears to be slight progression, since regression may occur later. Further research may be appropriate to elucidate the increasingly recognized effect of cannabis/cannabinoids on gliomas.
authors.affiliation: Division of Pediatric Neurosurgery, Department of Surgery, BC Children's Hospital, 4480 Oak Street, Vancouver, BC, Canada, V6H 3V4.
authors.forename: Mansoor
authors.initials: M
authors.lastname: Foroughi
authors.forename: Glenda
authors.initials: G
authors.lastname: Hendson
authors.forename: Michael A
authors.initials: MA
authors.lastname: Sargent
authors.forename: Paul
authors.initials: P
authors.lastname: Steinbok
mesh_terms: D000293:Adolescent; D001254:Astrocytoma / Q000473:pathology* / Q000601:surgery; D001932:Brain Neoplasms / Q000473:pathology* / Q000601:surgery; D002648:Child; D005260:Female; D020712:Fornix, Brain / Q000473:pathology* / Q000601:surgery; D006801:Humans; D001239:Inhalation; D008279:Magnetic Resonance Imaging; D008385:Marijuana Smoking; D009365:Neoplasm Regression, Spontaneous / Q000473:pathology*; D018365:Neoplasm, Residual / Q000473:pathology; D012688:Septum Pellucidum / Q000473:pathology* / Q000601:surgery