Presentation
Asthenia, adynamia, moderate to severe headache, gait lateralization, diplopia, decreased visual acuity and convergence of the left eye.
Patient Data
Non-contrast reformatted computed tomography is observed in axial, sagittal and coronal planes. At the level of the fourth ventricle with cerebellar origin, a round lesion with a heterogeneous appearance with calcification areas is observed that displaces the pons forward, obliterating the prepontine cistern. A hypodense area compatible with vasogenic edema is observed on the periphery of the lesion.
Post-surgical changes of suboccipital craniectomy and frontoparietal craniotomy for ventriculoperitoneal valve placement are observed, which is observed as a hyperdense image, with a tubular appearance directed to the ventricular region.
Note: The patient was admitted to the emergency department with data of intracranial hypertension and a previous tomography (Not acquired at this hospital) showed the lesion observed here. The present tomography is after the neurosurgery intervention to control intracranial hypertension because the previous study showed data of cerebellar tonsil herniation.
One year after surgical and chemotherapeutic treatment, a magnetic resonance study with sagittal cut in T1 and contrast-enhanced T1 is observed where post-surgical changes and total release of the fourth ventricle are observed.
Axial T2 sequence shows post-surgical changes suggesting the presence of cerebrospinal fluid occupying the area in the left cerebellar lobe where the tumor was located.
Immunohistochemical markers corresponding to classic medulloblastoma were performed.
CD56: Positive
Ki67: positive with high proliferation index
GFPA, EMA S-100: Negative
Macroscopic description:
Multiple tissue fragments that together measure 1.8 x 0.9 cm are received fresh from intraoperative study. They are irregular, reddish brown, and friable. Imprinting and frozen cutting is done.
Diagnosis of intraoperative study: Neoplasm of small, round and blue cells to be classified in the definitive study.
Multiple fragments referred to as fourth ventricle tumors were received in a bottle with formalin for intraoperative study, which together measure 4x4 cm and are light brown in color, irregular and soft. When cut, they are observed whitish-brown in color and with hemorrhagic areas. Representative sections are included.
Capsule ratio:
a) Cut by frozen; b) Rest of the frozen cut; c-e-) Representative of tumor.
Diagnosis: Referred to as "fourth ventricle tumor."
Histopathologically is compatible with classic medulloblastoma.
**Immunohistochemistry will be requested to complement the diagnosis.
Special proofs:
Immunohistochemistry.
Histochemistry.
Case Discussion
Medulloblastoma is the most common malignant tumor in children and presents a bimodality at 3-4 years and 8-9 years with a median of 5-7 years.
Although magnetic resonance imaging is the study of choice, due to the data on intracranial hypertension, it was decided to perform a non-contrast tomography.
Medulloblastoma is described as presenting a hyperdense behavior on non-contrast tomography.
The presence of calcifications is not common, occurring in 20-30% of cases.
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