Metastatic malignant melanoma

Case contributed by Dr Bruno Di Muzio

Presentation

Follow-up for brain cavernoma.

Patient Data

Age: 46-year-old
Gender: Male

MRI Brain

Modality: MRI

 

Technique: Multiplanar, multisequence imaging has been obtained through the brain including pre and post contrast sequences and time of flight MRA.

Comparison: Previous external MRI not available for comparison

Findings: On susceptibility weighted imaging six lesions demonstrate prominent signal loss, located in the right ventromedial thalamus, left cuneus, right occipitoparietal sulcus, left cingulate gyrus, left superior frontal gyrus and right postcentral gyrus. These have appearances consistent with cavernous malformations. The left sided cuneus lesion has a surrounding rim of vasogenic oedema suggesting recent haemorrhage.

The remainder of the brain is unremarkable in appearance. MR angiography is unremarkable, with no abnormal vessels are seen in these regions or elsewhere within the brain.

No developmental venous anomaly is identified.

Conclusion: Multiple cavernomas suggest autosomal dominant multiple cavernoma seen. Left occipital lobe cavernoma appears to have recently bled.

Some weeks later, the patient presented at the emergency department of a different hospital with cerebellar signs and symptoms. The neurologist requested a CT scan looking for acute bleeding.

Modality: CT

Technique: Non-contrasted volumetric acquisition through the brain. 

Findings: There is no intracerebral or subarachnoid haemorrhage. There is no extra-axial collection.

The basal cisterns and ventricles are unremarkable in their appearance and anatomy.

There is a hyperdense mass present within the superior right frontotemporal lobe measuring 2.3 cm x 2.7 cm in size. There is associated oedema. The mass appears to be durally based and may represent the presence of a meningioma. Correlation to any previous imaging is recommended. Further evaluation with contrast enhanced CT scan and MRI could be considered. The midline remains central.

There is an unremarkable appearance to the craniocervical junction and pituitary fossa. No orbital or retro-orbital abnormality is demonstrated. The visualised portions of the paranasal sinuses appear unremarkable. The mastoid air cells remain aerated.

No expansile or lytic osseous lesion is seen. No significant subgaleal haematoma is evident. No definite skull base or calvarial fracture is identified.

Conclusion: Hyperdense, likely extra-axial mass within the right frontotemporal lobe, with associated oedema. Correlation to previous imaging is recommended. Further assessment with contrast enhanced imaging and/or an MRI is recommended.

This last CT has showed a large hyperdense lesion in right postcentral gyrus in the same location as a cavernoma demonstrated on the previous MRI. The lesion has grown significantly larger since then. Such features infer an acute bleeding expanding a cavernoma or a different etiology, a new MRI scan was requested for a better assessment. 

MRI Brain

Modality: MRI

Technique: Multiplanar multisequence imaging including pre- and post-contrast T1, T2, FLAIR, DWI/ADC and MRA in accordance with the AVM protocol. Stereotaxis has also been performed.

Comparison: Previous MRI and CT. 

Findings: Right parietal mass measuring 10 x 13 x 12 mm has increased in size from 6 x 5 x 5 mm and has a broad dural attachment, most likely extra-axial in location. This lesion is hypointense on T1, intermediate on T2 and demonstrates vivid predominantly homogeneous contrast enhancement. Abutting the inferior margin of this mass in the right post-central gyrus is a new parenchymal region of signal abnormality measuring 20 x 26 mm. This demonstrates heterogeneous predominantly hypointense T2 and hypointense T1 signal associated with marked susceptibility artefact. The signal characteristics are those of subacute blood (intracellular methaemoglobin). There is surrounding vasogenic oedema and local mass effect in keeping with recent haemorrhage.

Multiple further lesions with susceptibility artefact in the left superior frontal gyrus, left cingulate gyrus, left occipital lobe and right occipital lobe at the junction of the parieto-occipital sulcus have all reduced in size and conspicuity. Previously demonstrated vasogenic oedema surrounding the left occipital lesion has resolved and this lesion is now predominantly hypointense on T1 and T2 sequences consistent with expected haemorrhage evolution. Lesion in the right medial thalamus is stable. These lesions do not demonstrate contrast enhancement and are consistent with cavernomas.

Assessment of DWI is hampered by the presence of blood product. Allowing for this, there is no true restricted diffusion evident. MRA is unremarkable. No developmental venous anomaly.

Conclusion: Recent haemorrhage in the right postcentral gyrus associated with vasogenic oedema and local mass effect. This is favoured to be secondary to an underlying cavernoma, and follow-up is recommended to ensure expected evolution. Adjacent to this haemorrhage, enhancing likely extra-axial mass has increased in size. The most likely diagnosis for this lesion is a meningioma, and given its fairly rapid growth the possibility of an atypical meningioma should be considered. Although the haemorrhage and mass are anatomically in close proximity, they are not felt to be part of a single unifying diagnosis. Multiple other lesions consistent with cavernomas have decreased in size. In the absence of a history of radiotherapy, these raise the possibility of autosomal dominant multiple cavernoma syndrome.

Modality: Pathology

 

MICROSCOPIC DESCRIPTION: The section shows fragments of a densely hypercellular tumour. This consists of a diffuse sheeted arrangement of markedly pleomorphic cells with large vesicular nuclei containing enlarged nucleoli and with a variable amount of pale cytoplasm. Frequent mitotic figures are identified. Tumour cells show strong nuclear immunostaining for SOX10 and strong cytoplasmic staining for tyrosinase. No staining for panctytokeratin AE1/AE3, cytokeratin CAM5.2, placental alkaline phosphatase (PLAP) or c-kit is seen in tumour cells. Numerous small lymphocytes and CD68+ monocyte-macrophages are admixed with tumour cells. The features are of metastatic malignant melanoma.

DIAGNOSIS: "?Cavernoma right postcentral gyrus": Metastatic malignant melanoma.

Case Discussion

This case illustrates a malignant melanoma metastasis developed in a patient with previous multiple cerebral cavernous malformations. 

Tumoural haemorrhage is a common feature of melanoma metastases. 

 

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Case Information

rID: 41336
Case created: 26th Nov 2015
Last edited: 28th Nov 2015
Tag: rmh
Inclusion in quiz mode: Included

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