Presentation
45 years old with past medical history of left atrial myxoma (recently excised) and benign melanocytic nevi, presenting with a four-month history of left-sided facial numbness and visual disturbance
Patient Data
Multiple discrete intraparenchymal subcortical hemorrhagic foci are demonstrated. Two lesions lie in the right frontal lobe and measure 11x26mm in diameter. An 18mm lesion lies in the right parietal lobe, a 3mm lesion lies in the left occipital lobe, and a tiny focus lies in the left frontal lobe. Assessment of enhancement is difficult given the intrinsic hyperdensity of these lesions, however, there appears to be enhancement of the left frontal lesion and probably the larger of the right frontal lesions. Moderate vasogenic edema surrounds each foci.
Findings are highly suspicious for hemorrhagic metastatic disease. In patients of this age, melanoma would represent the most common primary. Hemorrhagic metastases related to atrial myxoma are extremely rare, but have been reported.
The patient underwent stereotactic craniotomy and excision of both right frontal lesions. Histopathology, however, was inconclusive.
Histopathology: brain tissue: features of reaction to remote hemorrhage; no evidence of tumor seen. Further immunohistochemistry and special stains will be performed and a supplementary report issued.
SUPPLEMENTARY REPORT:
CD34 immunostaining highlights the intense vascularity of the lesion. No solid CD34 +ve tissue is seen. The features remain those of reactive vascular proliferation and resolving remote hemorrhage. Possible etiologies include embolus from atrial myxoma causing hemorrhagic infarction which is now resolving or the very remote possibility of a small metastasis of melanoma which has either undergone regression or has been destroyed by the local hemorrhage.
There were concerns that these lesions may represent malignant metastases, or an embolic phenomenon relating to this patient’s recently excised atrial myxoma. After further discussions between the neurosurgeons and the patient, two months later, in the hope of a definitive diagnosis, the patient underwent further surgery (stereotactic craniotomy and excision of right occipito-parietal metastasis).
Histopathology:
MICROSCOPIC DESCRIPTION:
1. The sections show fragments of cerebral cortex and white matter. The lumen of a superficial small caliber muscular artery is distended by myxomatous material containing stellate shaped myxoma cells. A poorly circumscribed collection of myxomatous material also containing myxoma cells is noted in cortex adjacent to this vessel. Myxoma cells are arranged singly, in cords and in peri-vascular pseudorosettes and have moderately pleomorphic round and oval hyperchromatic nuclei and delicate processes. No mitotic figures or areas of necrosis are identified. Adjacent brain tissue shows collections of hemosiderin filled macrophages consistent with previous hemorrhage and reactive proliferation of small capillaries. There is also moderate reactive astrocytic gliosis. The features are of embolic/metastatic myxoma consistent with an origin from atrial myxoma.
2. The sections show multiple fragments of cerebral cortex and white matter. These show foci of recent hemorrhage and reactive gliosis No evidence of tumor is seen.
3&4. The sections show fragments of fibrous tissue and an ectatic small caliber muscular artery in specimen 4. Specimen 3 contains a small nidus of small caliber vascular channels. These are lined by unremarkable endothelium. No evidence of tumor is seen in either specimen.
DIAGNOSIS:
1. Right occipital lesion: Embolic/metastatic myxoma arising from atrial myxoma.
2. Right occipital lesion: Cerebral cortex and white matter with non-specific reactive changes; no evidence of tumor seen.
3. Deep: Fibrous tissue containing a nidus of small caliber vascular channels; no evidence of tumor seen.
4. Abnormal artery: Ectatic small caliber muscular artery. No evidence of tumor seen.
Six months later, the patient re-presented with partial seizures of the right eye, and right lower limb.
Evidence of previous right frontoparietal and right occipitoparietal craniotomies and underlying resections
Several hemorrhagic lesions are identified:
- Left superior parietal lesion measures 12mm x 9mm
- Left frontal lesion measures 6mm x 5mm
- Left occipital lesion measures 13mm x 12mm.
- Right superior parietal lesion measures 6mm x 7mm.
These are all at grey-white matter junctions. Other smaller ones may also be present.
Mild vasogenic edema surrounds these lesions with mild localized mass effect on the cerebral sulci. Ventricular size is normal. No midline shift. Encephalomalacia in the right frontal and parietal lobes noted. Mastoid air cells and paranasal sinuses are normal.
Conclusion: Bilateral hemorrhagic intra-axial lesions since 8/12, in the given clinical context, almost certainly represent new hemorrhagic myxoma metastases.
The patient underwent a left parieto-occipital craniotomy and tumor excision.
Histopathology:
MICROSCOPIC AND MACROSCOPIC DESCRIPTION:
1&2: The sections show fragments of brain parenchyma. These are congested and contain collections of hemosiderin-filled macrophages. There is also mild reactive astrocytic gliosis. No evidence of tumor is seen. In particular no myxomatous tissue is identified.
3&4: The sections show transverse profiles of small caliber muscular arterial vessels. Perivascular collections of hemosiderin-filled macrophages are prominent in specimen 3. The vessels in specimen 4 show no specific diagnostic abnormality. No myxomatous tissue is identified in either specimen.
DIAGNOSIS:
1&2: Brain tissue: Congested brain parenchyma with reactive gliosis; no myxomatous tissue identified.
3&4: Aneurysmal vessels: Small caliber muscular arterial vessels with minor non-specific abnormalities; no myxomatous tissue identified.
The patient was advised for whole brain radiotherapy for his residual intracranial disease.
Case Discussion
Cardiac myxomas are the most common primary tumors affecting the heart and are thought to be derived from mesenchymal cells of the subendocardium 1. They are predominantly benign (approximately 75%) and frequently found in the left atrium (approximately 80% of lesions) 2. Despite their predominantly benign features, cardiac myxomas can spread to extra-cardiac sites, including cerebral tissue, muscles, bones, skin, eye, kidney and coronary arteries, and are thought to do so by embolization of tumor particles 3.
With regards to the neurological complications secondary to embolism from atrial myxoma, cerebral vascular disorders, such as infarcts, hemorrhages and intracranial aneurysms are the most common presentations 3-5. Very rarely, myxoma presents as a mass lesion in cerebral parenchyma or leptomeninges, and is termed as a ‘metastasis 4. This patient case demonstrates this particularly rare pathology.
Case courtesy of Dr. Frank Gaillard
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