Intracranial melanoma metastases

Case contributed by Dr Craig Hacking

Presentation

Right wrist weakness and facial droop.

Patient Data

Age: 75 years
Gender: Male

There is a 25 mm intraparenchymal hyperdense lesion within the left parietal lobe superiorly involving the motor and somatosensory cortex with adjacent vasogenic edema. Another 12 mm intraparenchymal hyperdense lesion is seen within the right temporal lobe inferiorly with some minimal adjacent edema. Both these lesions minimally enhance.

There are some periventricular white matter changes.

There is no midline shift. The basal cisterns are not effaced.

Conclusion

  • bilateral hyperdense abnormalities which mildly enhance with adjacent vasogenic edema. The appearance is concerning for hemorrhagic metastatic deposits. Common causes in an elderly male include melanoma, renal cell, lung and thyroid cancer.
  • CT of the chest, abdomen and pelvis is recommended to assess for a possible primary and stage any further metastatic disease

Chest

The lungs and pleural spaces are clear apart from atelectasis in the left lower lobe and dependent atelectasis in bothcostophrenic angles. No consolidation, suspicious pulmonary nodules, pleural effusions or pneumothorax.

There is a large slightly heterogeneous enhancing mass lesion in the right axilla. The lesion measures 13 mm in maximal short axis diameter and is consistent with nodal metastatic disease. No left axillary, hilar or mediastinal lymphadenopathy. There is degenerative disk disease throughout the thoracic spine. No destructive lesion demonstrated.

Abdomen/pelvis

There is a large irregular ill-defined mass lesion on the serosal surface of the hepatic flexure in the right upper quadrant measuring 100 x 85 x 70 mm in maximum dimensions with surrounding fat stranding. The lesion is extending into the lumen of the colon and there is no dilatation to suggestion obstruction. Medially, the mass is in contact with, and is possibly adherent to, loops of non-distended small bowel.

There is para-aortic lymphadenopathy measuring 15 mm in maximal short axis diameter consistent with nodal metastatic disease. Free fluid in the upper abdomen surrounds the liver and spleen. No free gas.

The liver contains no focal lesions. The portal and hepatic veins are opacified. The gallbladder is contracted. The pancreas, spleen, and right adrenal gland are normal.There is an abnormal irregular soft tissue density in the left upper quadrant that appears to communicate with the left adrenal gland and may represent adrenal or nodal metastatic disease. There are cortical cysts in both kidneys measuring up to 35 mm in maximum diameter.

There is abnormal soft tissue density in the right retroperitoneum inferior to the kidney measuring 19 mm maximal diameter. It may represent nodal or distant metastatic disease. There are bilateral inguinal herniae containing fat, larger on the left. Mild distal colonic diverticulosis noted.

Left buttock subcutaneous metastasis.

There is slight superior endplate deformities in the lumbar spine probably due degenerative change. No destructive skeletal lesion is detected.

Conclusion

The bowel lesion does not have the appearance for primary colonic malignancy. Multiple lesions and cranial findings in keeping with metastatic disease, with melanoma the favoured diagnoses given the peritoneal and subcutaneous distribution of lesions.

Two intra-axial enhancing mass lesions are demonstrated, the larger of the two located in the white matter of the left precentral gyrus, measuring 25 mm, and the smaller of the two located on the right in the fusiform gyrus of the right temporal lobe, measuring 10 mm in diameter. These demonstrate pronounced signal loss on echoplanar imaging, and intrinsic high T1 signal, consistent with blood product. They are surrounded by a moderate amount of vasogenic edema.

The remainder of the brain is unremarkable, with no other lesion is evident, and only a modest amount of chronic small vessel ischemic white matter change.

Conclusion

Features are consistent with hemorrhagic metastases. Presence of multiple metastatic deposits are seen on CT, including subcutaneous deposit in the left buttock suggests malignant melanoma as the most likely primary.

Case Discussion

The DDx for hemorrhagic brain mets are MR CT BB (see mnemonic):

The bowel lesion is serosally-based (representing a peritoneal deposit) and not a colonic mucosal lesion (i.e. colorectal cancer).

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Case information

rID: 36848
Published: 18th Jun 2015
Last edited: 22nd Nov 2018
Inclusion in quiz mode: Included

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