Case contributed by Dr Antonio Rodrigues de Aguiar Neto


The patient came from another service for a neurosurgical procedure at this hospital.

Patient Data

Age: 10 years
Gender: Male

Axial nonenhanced CT image shows a slightly heterogeneous midline posterior fossa mass in the cerebellar vermis. The fourth ventricle is obliterated and not seen.

Sagittal T1-weighted MR image shows the midline well-defined cerebellar mass, complete filling the fourth ventricle. The lesion has a low signal compared with the surrounding normal cerebellum. On sagittal and axial T2 WI, the tumor shows mild hyperintensity compared with normal brain tissue, with minimal surrounding vasogenic edema. Contrast-enhanced axial T1-WI shows mildly heterogeneous enhancement of the mass. The lesion presents with diffusion restriction, manifested by low ADC values, indicating high tumor cellularity.

Photomicrograph (hematoxylin-eosin)

Histological report after surgical removal: desmoplastic medulloblastoma,

Case Discussion

Medulloblastomas are a common malignant CNS tumor in the pediatric group 1,2,3,4, classified as WHO grade IV. The four major histopathological types consist of classic, desmoplastic-nodular, large cell/anaplastic, and extensive nodularity 2,3,4.

The WHO currently genetic classification divides medulloblastomas into four molecular subgroups, which are wingless-WNT, sonic hedgehog-SHH, group 3, and group 4 1,3,4. This genetic classification is more predictive of clinical behavior and prognostic than tumor histology. Besides, it can be helpful in surgical planning, radiotherapy, and chemotherapy specific treatments 1,3,4. MRI is an essential tool for predicting molecular medulloblastoma subgroups 1,4.

This case illustrates histologically proven desmoplastic medulloblastoma, in the midline - vermis/fourth ventricle location.

Case courtesy

  • Erick Cavalcante, MD - PGY-3, Radiology Resident, Department of Radiology
  • Antonio Rodrigues de Aguiar Neto, MD - Radiologist, Department of Radiology
  •  Hospital da Restauração – Recife, PE – Brazil

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