Presentation
Headache and walk disturbance. Previous history of colorectal tumor.
Patient Data
Technique: Pre and post contrast axial images were obtained through the brain.
Findings: There is a nodular solid mass within the paramedian aspect of the left cerebellar hemisphere, spontaneously hyperdense with heterogeneous attenuation and showing vivid peripheral contrast enhancement. A mild vasogenic edema due the mass effect is noted. Despite its proximity to the fourth ventricle, there is no compression over the ventricular system. The remainder brain is unremarkable.
Conclusion: A solid mass in the cerebellum most likely represents hemorrhagic metastasis, however further evaluation with MRI is advised.
Technique: Multiplanar, multisequence imaging has been obtained through the brain including pre and post contrast sequences.
Findings: Centered within the left inferior posterior cranial fossa, just to the left of the midline, there is a 27 mm ( craniocaudal ) x 23 mm ( AP ) x 19 mm mass which is of predominantly low signal intensity on T2-weighted imaging and isointense to grey matter on T1-weighted imaging. There is also low GRE signal. The mass demonstrates peripheral enhancement with some internal enhancing nodules mainly superiorly. The outline of the mass is slightly lobulated. There is mass effect with vasogenic edema, effacement of the cerebellar folia, mild compression of the fourth ventricle; however there is no evidence of obstructive hydrocephalus at this time.
No supratentorial mass is identified.
There is a small number of scattered FLAIR signal intensity within the white matter of cerebrum. Normal grey-white matter differentiation in the cerebrum. No restricted diffusion. Ventricles and basal cisterns are within normal limits.
Conclusion: Solitary left posterior cranial fossa mass compatible with a hemorrhagic metastasis. Primary brain neoplasm is a possibility considered less likely.
Case Discussion
This patient was submitted to a resection of the posterior fossa tumor and the diagnosis was confirmed as metastatic adenocarcinoma.
In cases like this one, where we have a solitary lesion in the cerebellar hemisphere in an older adult, there are not a lot of differential diagnosis to be considered:
- metastasis: the most common, by far.
- hemangioblastoma: the most common primary tumor in this age group; the majority present as a non-enhancing cyst associated with enhancing mural nodule. Solid tumor with blood products, as in this case, can also be a less common presentation.
- astrocytomas: are really rare in the posterior fossa.
Although not frequent, colorectal adenocarcinoma can produce hemorrhagic metastases like in this case.
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