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Unusual case of intraosseous primary intracranial malignant melanoma
Brando Guarrera1, Irene Coati2, Mario Giarletta3
1Neuroscience, Ospedale dell'Angelo-Mestre, Mestre, Italy.
Abstract:
Primary intracranial malignant melanoma (PIMM) represents 0.07% of central nervous system tumours; clinical behaviour and prognosis are not well documented. Preoperative diagnosis of PIMM is complex and it could be easily misdiagnosed, especially with malignant meningioma.We are reporting a case of a man with a history of rapidly arising motor slowing associated with urinary incontinence, presenting with mild convergent strabismus caused by paralysis in abduction in the right eye. A brain CT showed a lesion compatible with malignant spheno-orbital meningioma, and the patient underwent gross total resection. Intraoperatively, the blackish lesion infiltrated and eroded the bone; it was placed externally on the dura mater with a mild reaction and without attachment. Histological examination confirmed PIMM.Intraosseous localisation of PIMM has been observed in the basic bone structure of the oral cavity. We report the first intraosseous spheno-orbital PIMM case and present an embryological theory about how this unusual tumour can develop.
Insights
Primary intracranial malignant melanoma (PIMM) is rare and difficult to diagnose preoperatively. This report details the first intraosseous spheno-orbital PIMM case, offering a new embryological theory for its development.
Area of Science:
- Neuro-oncology
- Pathology
- Ophthalmology
Background:
- Primary intracranial malignant melanoma (PIMM) is a rare central nervous system tumor, accounting for only 0.07% of cases.
- Preoperative diagnosis of PIMM is challenging, often leading to misdiagnosis, particularly with malignant meningioma.
- Clinical behavior and prognosis of PIMM remain poorly documented.
Observation:
- A case is presented of a male patient with progressive motor slowing and urinary incontinence.
- Clinical presentation included convergent strabismus due to right eye paralysis in abduction.
- Brain CT revealed a lesion suggestive of malignant spheno-orbital meningioma.
Findings:
- Gross total resection was performed on the blackish lesion, which infiltrated and eroded bone.
- Intraoperative findings noted the lesion's external placement on the dura mater with minimal reaction and no attachment.
- Histological examination confirmed the diagnosis of primary intracranial malignant melanoma (PIMM).
Implications:
- This case represents the first reported instance of intraosseous spheno-orbital PIMM.
- The study proposes a novel embryological theory for the development of this unusual tumor location.
- Understanding rare PIMM presentations is crucial for accurate diagnosis and improved patient outcomes.
