Case History
- White male
- 49 years old
- From São Paulo
- Previously healthy
- The patient reported severe holocranial headaches. In the same month, he began experiencing spasms in the right foot.
December 2023
- Severe, bilateral headaches.
- The first seizure involvingright foot spasms.
February 2024
- New episode of severe headache with a hypertensive peak.
March 2024
- Generalized tonic-clonic seizures;
- Right hemibody weakness.
Physical Examination
- Dysarthric.
- Complete right-sided hemiparesis
- Laboratory: normal
Diagnostic Hypothesis
February 2024 – CT
- Extra-axial hemorrhage
February 2024 – MRI
- Diagnostic Hypothesis: Subarachnoid hemorrhage? Expansive lesion?
March 2024 – CT
- Intraparenchymal hemorrhage: Vascular malformation? Expansive lesion?
Differential diagnosis
Arteriovenous malformation
Congenital abnormal connections between cerebral arteries and veins (arteriovenous shunting).
Imaging features:
- Nidus (*) within the brain parenchyma(CT, MRI or conventional angiography);
- Early venous drainage (conventional catheter angiography).
Diagnostic Hypothesis
March 2024 – MRI
- The evolutionary aspect of the content is not typical for hematic content.
- Extra axial lesion
- Apparently expansive
- Stability
- Enhancement
- T1WI: Hyperintensity
- High protein content of a nonhematic nature -> Melanin – Metastatic melanoma?
Clinical Case Report
Radiological Diagnosis: Expansive lesion containing melanin
Most common sites of melanoma metastasis: skin and subcutaneous tissue, followed by the lungs, liver, bones and brain.
- Normal thoracic, abdominal and pelvic CT scans.
Differential diagnosis
Primary melanocytic neoplasms of the CNS
Meningeal melanocytoma:
- Slow-growing,
- Typically benign neoplasms;
- 5th decade of life.
Imaging features
- CT:
Extra-axial
Iso- to hyperattenuating lesions;
Post-contrast enhancement.
- MRI:
Iso to hyperintensity on T1-weighted;
Hypo to isointensity on T2-weighted sequences;
Homogeneous enhancement post-gadolinium.
Pathologic and Histologic Features
- Grossly: mostly black / reddish-brown.
- Microscopically: cellular nests or whorls.
- Immunohistochemistry: expression of melanocytic markers.
Primary leptomeningeal melanomatosis:
- Aggressive;
- Diffuse growth pattern;
- 4th decade of life.
Imaging Appearance
- Diffuse leptomeningeal thickening
- Abnormal enhancement post-contrast.
- T1: iso to hyperintense. areas (melanin’s paramagnetic properties)
- T2: hypointensity.
Pathologic and Histologic Features
- Grossly: diffuse darkening and thickening of leptomeninges.
- Histologically: Polygonal neoplastic cells with cytoplasmic pigment and prominent nucleoli.
