Melanoma and pigmentation of the leptomeninges in Ugandan Africans

The landscape of neuro-oncology in East Africa: a review of published records

INTRODUCTION

Primary central nervous system (CNS) tumors represent an important and growing cause of worldwide morbidity and mortality. There are global variations in the reported case burden of CNS tumors, with high-income countries reporting a higher incidence of cases than low- and middle-income countries. Variations are attributed to differences in access to care, diagnostic capacity, risk exposure, and under-reporting in LMICs. This study aims to review existing literature on the distribution of primary CNS tumors and neuro-oncologic care, and the contribution of scientists and institutions to neuro-oncologic research across 18 East African countries over the last 5 decades.

METHOD

A search was conducted using OVID Medline and PubMed databases to identify relevant East African neuro-oncologic studies published over the last 50 years.

RESULTS

The authors reviewed 36 neuro-oncology articles published across 8 of 18 East African countries. Kenya represented the highest number of published articles; ten countries queried yielded zero publications. A total of 2006 cases from all age groups were represented in published literature consisting of a wide spectrum of CNS tumors. One-third of reported cases were pediatric. Meningioma formed the largest proportion (43.3%) followed by glioma (33.7%). Sixty-seven percent of publications gave an overview of clinical care received by patients with most patients not receiving comprehensive neuro-oncologic care.

CONCLUSION

The modest collection of neuro-oncology publications from East Africa shows that the case diversity of primary CNS tumors in East Africa is comparable to the rest of the world. There is, however, poorer access to neurosurgical care and adjuvant therapy. Multidisciplinary efforts from clinicians, researchers, and healthcare agencies are needed to quantify and address the requisite neuro-oncology needs in this region.

Clinicopathologic features and pathogenesis of melanocytic colonization in atypical meningioma

Only two prior cases of benign dendritic melanocytes colonizing a meningioma have been reported. We add a third case, describe clinicopathologic features shared by the three, and elucidate the risk factors for this very rare phenomenon. A 29 year-old Hispanic woman presented with headache and hydrocephalus. MRI showed a lobulated enhancing pineal region mass measuring 41 mm in greatest dimension. Subtotal resection of the mass demonstrated an atypical meningioma, WHO grade II, and the patient subsequently underwent radiotherapy. She presented 4 years later with diplopia, and MRI showed an enhancing extra-axial mass measuring 47 mm in greatest dimension and centered on the tentorial incisura. Subtotal resection showed a brain-invasive atypical meningioma with melanocytic colonization. The previous two cases in the literature were atypical meningiomas, one of which was also brain invasive. Atypical meningiomas may be at particular risk for melanocytic colonization as they upregulate molecules known to be chemoattractants for melanocytes. We detected c-Kit expression in a minority of the melanocytes as well as stem cell factor and basic fibroblast growth factor in the meningioma cells, suggesting that mechanisms implicated in normal melanocyte migration may be involved. In some cases, brain invasion with disruption of the leptomeningeal barrier may also facilitate migration from the subarachnoid space into the tumor. Whether there is low-level proliferation of the dendritic melanocytes is unclear. Given that all three patients were non-Caucasian, meningiomas in persons and/or brain regions with increased dendritic melanocytes may predispose to colonization. The age range spanned from 6 years old to 70 years old. All three patients were female. The role of gender and estrogen in the pathogenesis of this entity remains to be clarified. Whether melanocytic colonization may also occur in the more common Grade I meningiomas awaits identification of additional cases.

Meningeal Melanocytes in the Mouse: Distribution and Dependence on Mitf

Summary: Melanocytes are pigment producing cells derived from the neural crest. They are primarily found in the skin and hair follicles, but can also be found in other tissues including the eye, ear and heart. Here, we describe the distribution of pigmented cells in C57BL/6J mouse meninges, the membranes that envelope the brain. These cells contain melanosomes of all four stages of development and they depend on Microphthalmia associated transcription factor (MITF), the master regulator of melanocyte development, suggesting that they are bona-fide melanocytes. The location of these pigmented cells is consistent with the location of meningeal melanomas in humans and animal models.

Significance: Here, we document and define pigmented cells in the meninges of the mouse brain and confirm that they are melanocytes. This is important for understanding the role of this cell type and for understanding primary meningeal melanoma, a rare disease that likely arises from normal meningeal melanocytes.

Neurocutaneous melanosis: report of three cases and up-to-date review

Neurocutaneous melanosis is a rare noninherited embryonic neuroectodermal dysplasia, which is observed sporadically and never affects the entire integument. The hallmark of neurocutaneous melanosis in the neonatal period is the presence of a large bilateral hairy dark nevus with satellite nevi over the trunk and neck. The diagnosis should be considered in neonates with large pigmented nevi and in those with more than 3 hairy dark nevi regardless of their size. Neonates with neurocutaneous melanosis are at risk of developing neurological problems. The most common neurological complications are hydrocephalus, seizures, cranial nerve dysfunction, and signs of spinal cord and root involvement. The authors report 3 cases of histologically confirmed neurocutaneous melanosis and describe the course of neurological symptoms and clinical findings including cognitive tests and neuroimaging. The case reports are complemented by an up-to date review on this clinical entity.

Neurocutaneous melanosis: a case of primary intracranial melanoma with metastasis

Neurocutaneous melanosis is a rare disorder characterized by the presence of large or multiple congenital melanocytic naevi and benign or malignant pigment cell tumours of the leptomeninges. Distant metastasis is unusual in primary leptomeningeal/intracranial melanomas. We present the case history of an adult male who had multiple primary intracranial melanomas associated with neurocutaneous melanosis (naevus of Ota) in the ophthalmic division of the left trigeminal nerve. Excision of the intracranial tumours was carried out in two stages, but the patient died 2 days after the second operation. Autopsy showed multiple metastatic deposits in the liver. Symptoms and signs of raised intracranial pressure, the presence of Ota's naevus, and a dural-based mass or masses should alert the treating physician to suspect a primary leptomeningeal/intracranial melanoma.

Leptomeningeal melanomatosis with multiple cutaneous pigmented nevi: tumor cell proliferation and malignant transformation in an autopsy case

We experienced a rare case of leptomeningeal melanomatosis. The proliferative activity and nuclear accumulation of p53 in this tumor were examined, since the relationship between this tumor type and growth has not yet been elucidated. A 33-year-old Japanese man was shown to have leptomeningeal melanomatosis with multiple cutaneous pigmented nevi. The autopsy findings showed the presence not only of benign diffuse melanosis of the leptomeninges but also of leptomeningeal melanomatosis in the subarachnoid space and brain parenchyma. In the brain parenchyma, the direct invasion of tumor cells from the subarachnoid space and Virchow-Robin spaces filled with melanoma cells were observed. Multiple hemorrhagic areas invaded by melanoma cells were also present. Immunohistochemical staining with a monoclonal antibody to melanoma cells showed positivity in the tumor cells. Proliferation analysis using the MIB-1 antibody demonstrated that the labeling index of tumor cells invading brain parenchyma (2.54%) was higher than that in other lesions of the inner (0.89%) and outer layer (0.76%) of the subarachnoid space. Nuclear accumulation of p53 protein was rarely seen in the tumor cells. We reported a case of leptomeningeal melanomatosis. Higher proliferative activity was found in invading cells of the brain parenchyma. Malignant transformation of the tumor did not appear to be associated with p53 gene mutation.

Primary leptomeningeal melanoma: an unusually aggressive tumor in childhood

Primary malignant melanoma of the leptomeninges of the central nervous system is a rare and aggressive tumor in children. We report our experience from 1964 to 1990 with this tumor in eight children. The mean age at diagnosis was 4.9 years (range, 1.3 to 13 yr). Five children presented with signs and symptoms of raised intracranial pressure from hydrocephalus secondary to tumoral obliteration of the basal cisterns, but the time from the initial symptomatology to diagnosis was frequently delayed. Three patients in this series had hairy nevi in association with their leptomeningeal melanoma. Cerebrospinal fluid (CSF) analysis typically showed raised opening pressures, decreased glucose, and increased protein concentrations. Malignant melanoma cells were found in the CSF in three patients. Confirmatory radiographic examinations included air encephalography, myelography, and computed tomographic and magnetic resonance scanning. Four patients were treated with lumboperitoneal shunts, and one patient was treated with a ventriculoperitoneal shunt for hydrocephalus. Two patients underwent craniotomies and subtotal excisions of their tumors. In seven patients, a definitive diagnosis of leptomeningeal melanoma was made by pathological examination of tissues sent at surgery or at post mortem. In one case, the diagnosis was established by a detailed cytological analysis of the CSF. Four children died of fulminant disease and tumor spread before treatment could be instituted. The four children who received treatment had a combination of radiation therapy and chemotherapy. One child received intrathecal methotrexate. The two children with the longest survivals (2 and 3 yr, respectively) received cisplatinum and dimethyltriazenoimidazole carboxamide in addition to craniospinal irradiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary solitary intracranial melanoma: case report and review of the literature

Among CNS tumors, intracranial melanomas represent a subject of interest for neurooncologists and neurosurgeons because clinical and radiological patterns of these tumors can mimic the presence of meningiomas, and in spite of their malignant behavior they can be satisfactorily treated. In the present report we describe a new case of primary intracranial melanoma that displayed some radiological features of meningioma; we review the clinical features of 80 previously well-documented cases. The importance of neuroradiological and histochemical (S-100 protein, antimelanin antibodies, proliferating cell nuclear antigen staining) methods and of flow cytometry in helping with histopathological examination is stressed. Review of the clinical histories demonstrates that surgical excision is recommended in most cases, depending on tumor location, and that if total removal is performed, long-term disease-free periods can be attained.