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Melanotic cerebral astrocytoma: case report and literature review
T Kanzawa1, H Takahashi, M Hayano
1Department of Neurosurgery, Mito Saiseikai General Hospital, Japan.
Abstract:
We describe the case of 47-year-old man with a cystic, melanotic temporal lobe astrocytoma who had a history of complex partial seizures. The tumor mass was made up of two histologically different regions: one consisted of spindle-shaped and pleomorphic cells often with foamy or vacuolated cytoplasm, while the other consisted of fairly uniform spindle-shaped cells, many of which contained dark-brown intracytoplasmic pigment. Desmoplasia was also noted in the latter region of the tumor. No features suggestive of malignancy, such as mitotic figures, necrotic foci or endothelial vascular proliferation, were observed throughout the tumor. Immunohistochemically, the tumor cells in both regions were positive for glial fibrillary acidic protein. Ultrastructural examination of the pigmented region showed the presence of melanosomal melanin in the tumor cells. Apart from the partial pigmentation, the entire histological picture resembled a pleomorphic xanthoastrocytoma. To our knowledge, only two cases of similar melanotic astrocytic tumors have been described previously. Interestingly, the astrocytic tumors in both of these patients were also clinically associated with epilepsy, were located in the temporal lobe, and were histologically benign.
Insights
This study details a rare melanotic astrocytoma in a temporal lobe tumor, presenting benign features and intracytoplasmic pigment. This finding contributes to understanding rare brain tumors and epilepsy associations.
Area of Science:
- Neuro-oncology
- Neuropathology
Background:
- Astrocytomas are primary brain tumors arising from astrocytes.
- Melanotic astrocytomas are rare variants characterized by melanin pigment within tumor cells.
Observation:
- A case of a 47-year-old male with a cystic, melanotic temporal lobe astrocytoma and a history of complex partial seizures is presented.
- The tumor exhibited two distinct histological regions: one with pleomorphic cells and another with pigmented, uniform spindle cells showing desmoplasia.
- Immunohistochemistry confirmed glial fibrillary acidic protein positivity in tumor cells, and ultrastructural analysis revealed melanosomal melanin.
Findings:
- The melanotic astrocytoma was histologically benign, lacking features of malignancy.
- The tumor shared similarities with pleomorphic xanthoastrocytoma, apart from the melanotic component.
- This represents one of the few documented cases of melanotic astrocytic tumors, particularly those associated with epilepsy.
Implications:
- This case expands the understanding of rare melanotic astrocytic tumors.
- The association with epilepsy highlights a potential clinical correlation for these rare neoplasms.
- Further research into melanotic astrocytomas may elucidate their pathogenesis and clinical behavior.