Neurosurgery notes/Tumours/Choroid plexus tumours/Atypical choroid plexus papilloma

Atypical choroid plexus papilloma

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Choroid plexus tumours

Definition

  • Essential:
    • Intraventricular or cerebellopontine angle location AND
    • Demonstration of choroid plexus differentiation by histopathological and immunophenotyplc features AND
    • Demonstration of >=1 mitosis/mm2 in a minimum of 2.3 mm2 (equating to >=2 mitoses/10 HPF of 0.23 mm2) AND
    • Absence of criteria qualifying for the diagnosis of choroid plexus carcinoma
  • Desirable:
    • In select cases: demonstration of hyperploidy by genome-wide chromosomal copy-number analysis

Numbers

  • 7.4% of choroid plexus tumours

CNS WHO grading

  • Grade 2

Origin

  • Same as choroid plexus papilloma

Localization

  • Typical choroid plexus papilloma occur in the supratentorial and infratentorial regions with nearly equal frequency, atypical choroid plexus papilloma are more common within the lateral ventricles
    • 83% lateral ventricles,
    • 13% in the third ventricle,
    • 3% in the fourth ventricle

Histopathology

  • Highly vascular tumour with a propensity to bleed
  • Choroid plexus papilloma with increased mitotic activity (> 2 mitoses per 10 randomly selected high-power fields)
  • Negative S100 protein staining in > 50% of the tumour cells has been associated with a more aggressive clinical course
  • Inverse correlation has been found between transthyretin (greater stain) staining intensity and rate of local recurrence (lower recurrence)
  • Immunohistochemical profile of atypical choroid plexus papilloma, including positivity for KIR7.1, is similar to that of choroid plexus papilloma

Clinical presentation

  • Same

Radiological

  • MRI characteristics have been reported between choroid plexus papilloma and atypical choroid plexus papilloma

Treatment

Surgery

  • Pre op
    • Correction of hydrocephalus
    • CTA/DSA
      • Pre op embolization
  • Aim
    • Maximal safe surgical resection.
  • Technique
    • High bleeding risk needs cross match
  • Post op
    • Surgical surveillance for localised CPP.
      • If there is local progression,
        • Second surgery should be considered.
        • Proceed chemo right after 2nd surgery
      • Complete remission
        • Then consider a watch and wait policy.

Chemotherapy

For local disease

  • If there is residual localised disease following primary surgery and the patient is less than 1.5 years of age, a watch and wait strategy may be employed as per CPP with residual disease.
  • If there is residual localised disease following primary surgery and the patient is older than 3 years, give chemotherapy with 6 cycles of CarbEV.
    • Assess for response after every 2 cycles and consider second look surgery.
  • If there is residual localised disease following primary surgery and the patient is between 1.5 and 3 years, give chemotherapy with 6 cycles of CarbEV.
    • Assess for response after every 2 cycles and consider second look surgery.
    • Although it is likely this group have an excellent outcome, until there is clearer data and consistent methylation status, it is not felt treatment can be de-escalated.

For metastatic disease

  • Following surgery for metastatic APP, 6 cycles of CarbEV chemotherapy should be given.
    • Response should be assessed after every 2 cycles and second look surgery should be considered.

Radiotherapy

  • Indication
    • Once multiple surgical procedures and chemotherapy options are exhausted without achieving a complete response or with progression of disease.
      • Localised APP
        • < 3 yrs age
          • Locally progressing after repeated surgical procedures + chemotherapy
            • Focal radiotherapy may be indicated in those > 1.5 years of age.
            • There is no robust evidence to dictate the RT approach and RT-related toxicity is considerable
          • With unresectable residual
            • Residual disease may remain stable for prolonged period and watch and wait is preferred.
            • There is no robust evidence to dictate the RT approach and RT-related toxicity is considerable.
        • > 3 years of age
          • With unresectable residual OR
          • Locally progressive disease post chemotherapy without surgical options -
            • There is no robust evidence to dictate the RT approach and RT-related toxicity is considerable.
            • Stable unresectable residual at the end of treatment
              • Watch and wait OR
              • Upfront local radiotherapy
                • Acceptable and most European centres tend towards upfront local radiotherapy as per the SIOP CPT studies.
            • Progressive disease
              • Local radiotherapy
      • Metastatic APP
        • Craniospinal radiotherapy
          • In patients > 3 years with residual or progressive disease post chemotherapy. OR
        • Watch and wait
          • Complete response to surgery and chemotherapy,
          • For those <3 years, watch and wait would be preferred
        • Radiotherapy reserved for residual or progressive disease
    • Radiotherapy advice refers to patients without Li-Fraumeni syndrome and active exclusion of TP53 mutations.
  • Options
    • Proton therapy
      • Indication:
        • If radiotherapy is to be given with curative intent

Prognosis

  • 17% can spread
  • 5-year overall survival: 89%
  • Event-free survival: 83%
  • Atypical choroid plexus papilloma is prognostically relevant in children aged > 3 years and in adults, but not in children aged < 3 years, who may have good prognosis even with choroid plexus papilloma with high proliferation