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Pineal Tumour of Intermediate Differentiation

Summary

  • Rare neoplasm of the pineal gland with mixed features of pineocytoma and pineoblastoma
  • Clinical presentation includes headache, visual disturbances, and Parinaud syndrome
  • Imaging shows a well-defined, heterogeneous mass in the pineal region with variable enhancement1

Pathophysiology

  • Arises from pineal parenchymal cells
  • WHO grade 2 or 3 tumour, depending on mitotic activity and neurofilament protein expression
  • Exhibits intermediate differentiation between pineocytoma and pineoblastoma
  • May show areas of necrosis and calcification

Demographics

  • Rare tumour, accounting for <0.1% of all intracranial neoplasms
  • Typically affects young adults and middle-aged individuals
  • No significant gender predilection reported

Diagnosis

  • Clinical presentation:
    • Headache
    • Visual disturbances
    • Parinaud syndrome (vertical gaze palsy, convergence-retraction nystagmus)
    • Hydrocephalus due to compression of the cerebral aqueduct
  • Histopathology:
    • Moderate cellularity with diffuse growth pattern
    • Intermediate nuclear-to-cytoplasmic ratio
    • Mild to moderate nuclear atypia
    • Immunohistochemistry positive for synaptophysin and neurofilament protein

Imaging

  • CT:
    • Well-defined, hyperdense mass in the pineal region
    • Variable calcification patterns
    • Contrast enhancement may be heterogeneous
  • MRI:
    • T1: Iso- to hypointense
    • T2: Iso- to hyperintense
    • T1 post-contrast: Heterogeneous enhancement
    • DWI: Variable restricted diffusion
    • MR spectroscopy: Elevated choline peak, reduced N-acetylaspartate

panels-1

  • A 50-year-old patient presented with a 6 month history of occipital headaches.
  • MRI showed a lesion in the pineal region. A large vein within the lesion indicated that the lesion was extra-axial.
  • Following resection, a pineal tumour of intermediate differentiation (grade 3) was diagnosed.

Treatment

  • Resection with adjuvant radiotherapy; craniospinal irradiation for disseminated disease

Differential diagnosis (pineal region mass)

Imaging differential Differentiating feature
Pineoblastoma Larger, more heterogeneous and aggressive, with "exploded" peripheral calcification and marked diffusion restriction (WHO grade 4)
Pineocytoma Small (<3 cm), well-defined, often cystic, indolent (WHO grade 1)
Germinoma Engulfed central calcification, avid homogeneous enhancement and restricted diffusion, in a young male, with raised markers (β-hCG/PLAP)
Pineal cyst Thin-walled CSF-signal cyst without a solid enhancing nodule
Tectal/pineal region glioma Arises from the tectum, expanding it, rather than a discrete pineal mass

  1. Takase et al. Pineal parenchymal tumor of intermediate differentiation: a systematic review and contemporary management of 389 cases reported during the last two decades. 2022. Neurosurgical review - Open in new tab. ↩