Intracranial meningeal melanocytoma: a report of two cases and a review of the literature

Malignant Transformation and Leptomeningeal Melanomatosis in a Primary Meningeal Melanocytoma: A Case Report and Review of Literature

Meningeal melanocytomas of the central nervous system, although typically benign, rarely undergo malignant transformations. A 46-year-old man presented with headache and nausea 4 years after gross total resection of a craniovertebral junction meningeal melanocytoma at another hospital. The initial clinical course was previously reported.1) Computed tomography revealed the presence of multiple intracranial mass lesions. Furthermore, magnetic resonance imaging showed multiple intracranial lesions and meningeal dissemination. A biopsy was performed for a circumflex lesion located in the right frontal lobe. Pathological examination showed anaplastic changes and a Ki-67 index of 33%. Based on the pleomorphic changes and high mitotic activity, the patient was diagnosed with primary cerebral malignant melanoma. The patient received four cycles of nivolumab (80 mg) and ipilimumab (165 mg), followed by whole-brain radiotherapy (37.5 Gy). However, the disease progressed after the third cycle. Genome analysis revealed GNAQ Q209P and SF3B1 R625C mutations, but no treatments related to these gene mutations were available. Despite the seven cycles of nivolumab therapy, the patient eventually passed away 9 months after surgery. This case was a rare example of malignant transformation and leptomeningeal melanomatosis in a meningeal melanocytoma. It highlights the importance of careful follow up after gross total resection. Identification of molecular alterations can lead to better detection of melanocytic melanomas with poor prognosis and high risk of recurrence and metastasis. It can also facilitate the development of novel therapeutic options for these patients.

How Should We Treat Meningeal Melanocytoma? A Retrospective Analysis of Potential Treatment Strategies

BACKGROUND

Meningeal melanocytomas (MM) are rare primary melanocytic tumors of the leptomeninges with an incidence of 1:10,000,000. Until now, there has been only sparse information about this tumor entity. Here, we provide a meta-analysis of all cases published in the English language since 1972.

METHODS

A literature review was performed using PubMed and Web of Science. All published cases were evaluated for location, sex, age, therapeutic approach, and outcome. In total, we included 201 patient cases in our meta-analysis.

RESULTS

The majority of MM was diagnosed more frequently in men between the third and fifth decade of life. Surgery is the preferred therapeutic approach, and total resection is associated with the best outcome. Patients with partial resection or tumor recurrence benefit from adjuvant radiotherapy, whereas chemo- or immunotherapies do not improve the disease course. Malignant transformation was described in 18 patients. Of these, 11 patients developed metastasis.

CONCLUSIONS

We present the first retrospective meta-analysis of all MM cases published in the English language, including an evaluation of different treatment strategies allowing us to suggest a novel treatment guideline highlighting the importance of total resection for recurrence-free survival and characterizing those cases which benefit from adjuvant radiotherapy.

Intracranial meningeal melanocytomas: Clinico-radiological characteristics and outcomes. A Literature review

OBJECTIVES

Melanocytes are neural crest derivatives. Intracranial meningeal melanocytomas (MM) are rare tumors and the available literature is sparse for these neoplasms. This present review aims to provide a detailed and comprehensive literature review of these tumors.

MATERIALS AND METHODS

By searching online databases, literature review was performed to include and analyze all cases of cranial MM reported till date. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for the review process.

RESULTS

A total of 109 cases were analyzed. Male:female ratio was 1.2:1. The mean age was 40.3 years. The mean duration of symptoms was 23.9 months (range 2days-15 years). Cerebellopontine (CP) angle, suprasellar and Meckel cave were the most common locations. Sixty-four cases (58%) underwent GTR. Twenty-eight patients (26%) received some form of adjuvant radiation. There were 29(26%) recurrences and mean time to recurrence was 50.2 months. The recurrence rates (RR) for GTR and STR were 20% and 42% respectively. Extent of resection (STR) and tumor locations (CP angle and Meckel cave) were significantly associated with higher RR. Six (6.5%) cases had higher-grade transformations.

CONCLUSIONS

Complete surgical resection is the ideal treatment and adjuvant radiation is to be considered for residual/recurrent tumors. Adjuvant radiotherapy may also be prescribed despite GTR, in locations with higher RR such as CP angle and Meckel's cave. Because of higher-grade transformations and delayed recurrences, long-term follow-up is required.

Stereotactic radiosurgery for intracranial primary melanocytomas

OBJECTIVE

The role of stereotactic radiosurgery (SRS) in the management of recurrent and residual intracranial primary melanocytomas (PMC) remains unclear. The aim of this study is to evaluate the safety and efficacy of SRS in the management of these rare tumors.

METHODS

One patient treated with SRS in our institution for an intracranial PMC was retrospectively identified. Additionally, a systematic review of English articles using MEDLINE was performed to identify studies reporting on treatment and tumor characteristics and patient outcomes following SRS-management of intracranial PMC.

RESULTS

Including our institution's patient, a total of 13 patients (11 males and 2 females) met the inclusion criteria and were analyzed. The median age at SRS treatment was 49 years [Interquartile range (IQR) 27]. At a median follow-up of 24 (IQR 48) months, the aggregate local tumor-control rate was 76.9%. Progression occurred in three patients and was managed with repeat SRS (1/13) or salvage resection (2/13). One case of malignant transformation to melanoma leading to leptomeningeal dissemination and death was noted.

CONCLUSION

SRS appears to be a reasonable treatment option for recurrent and residual melanocytomas. A higher prescription dose might be reasonable in the treatment of intermediate grade or recurring PMC. Close longitudinal follow up for recurrence or malignant transformation of melanocytomas after SRS is recommended.

Recurrent Meningeal Melanocytoma of Cervical Spine: A Rare Case

Melanocytomas of the central nervous system are rare benign or intermediate grade localized melanocytic tumors. Despite its benign nature, it can follow a locally aggressive course with propensity to recur. We present the case of a 29 years old female who presented with a recurrent lesion in cervical spine and rapidly progressing quadriparesis. On examination, there was loss of power in right-sided extremities and reduction in sensations in left-sided extremities. Magnetic resonance imaging spine revealed a homogeneously enhancing intradural extramedullary dumbbell-shaped mass lesion at C4/5 level with extension through right C4 neural foramina to the extraforamina space, causing severe spinal cord compression. Intraoperatively, bluish-colored tumor was identified along with underlying hematoma. Gross total excision of the tumor was done. Tumor was received in the histopathology department in multiple black-colored fragments. Microscopically, a heavily pigmented tumor was seen with the sheets and nodules of polygonal cells with large nuclei and prominent nucleoli. Differentials considered were meningeal melanocytoma and malignant melanoma. On immunohistochemistry, the tumor cells showed diffuse positivity for HMB 45 and S100. Ki 67 index was around 1%. On radiological review, the tumor was fairly well circumscribed and did not infiltrate the adjacent tissues. There was no evidence of any lesions elsewhere in the body. Considering these features, the tumor was diagnosed with meningeal melanocytoma. Postoperatively, there was significant immediate improvement in quadriparesis and patient could walk with minimal support.

[Intramedullary melanocytoma: a clinical case report and literature review]

The paper describes a rare clinical case of intramedullary melanocytoma, provides a detailed description of a pathomorphological study, and addresses the issues of differential diagnosis and surgical treatment.

Sudden Death and Primary Leptomeningeal Melanocytosis: A Case Report With an Autopsy Diagnosis

Meningeal melanocytoma is a rare benign pigmented tumor. It develops from melanocytes normally present in the meninges of the posterior fossa and medulla. It is an extra-axial tumor that manifests because of compression of adjacent structures. Although classified as a benign tumor, it can cause sudden death by several mechanisms. We report a rare case of meningeal melanocytoma and discuss the mechanism of death. A 21-year-old man with a previous history of recurrent lipothymia was admitted to the emergency department because of generalized seizures. Death occurred despite resuscitation. A medico-legal autopsy was performed. External examination of the body showed nonspecific asphyxia signs without any violence evidence. Necropsy noticed a brain edema with a dark color of the meninges especially in the frontal part. Histological examination concluded to diffuse meningeal melanocytoma with cerebral edema.

Primary meningeal melanocytoma of the sellar region: review of the literature and differential diagnosis with special reference to angiographical features

PURPOSE

Primary intracranial melanocytomas are rare neoplasms, especially in the sellar region. Intracranial melanocytoma is usually a dural-based tumor, fed by dural arterial branches in a manner similar to meningioma. Primary sellar melanocytoma may be misdiagnosed as hemorrhagic pituitary macroadenoma, spindle cell oncocytoma, and intrasellar meningioma. These tumors differ in some radiological respects, but are difficult to differentiate preoperatively.

METHODS

Only five cases of primary sellar/suprasellar melanocytic tumors, excluding melanomas have been reported thus far. In this paper, we report an instructive new case of a 31-year-old woman presenting with a 2-year history of amenorrhea and an intrasellar mass with suprasellar extension, suggestive of hemorrhagic pituitary adenoma.

RESULTS

Transsphenoidal surgical excision was difficult due to extensive bleeding from the lesion, and at the time, the tumor could not be diagnosed histopathologically. Six years later, we operated again because of tumor regrowth. Angiography revealed a hypervascular tumor, which was fed from the dorsal sellar floor. We had difficulty resecting the tumor, but achieved total removal. Our case had typical radiographic characteristics of melanocytoma, revealed by both magnetic resonance imaging and angiography. However, it was difficult to reach a final diagnosis. Further histopathological examination, including immunohistochemical and ultrastructural studies, was helpful for diagnosis of melanocytoma.

CONCLUSIONS

Primary sellar melanocytic tumors are derived from melanocytes in the meningeal lining of the sellar floor or in the diaphragm sellae, based on both embryological assumptions and the clinical findings of our case. We discuss the problems of differential diagnosis and management of primary sellar melanocytic tumors.

Primary Meningeal Melanocytoma in the Left Temporal Lobe Associated with Nevus Ota: a Case Report and Review of the Literature

BACKGROUND

Primary melanocytic neoplasms of the central nervous system are rare lesions arising from melanocytes of the leptomeninge that are found at highest density underneath the brain stem and along the upper cervical spinal cord. Thus most reported cases of meningeal melanocytomas are located in the posterior fossa and the spinal cord, and presentation of a supratentorial tumor is rare.

METHODS

A 19-year-old man presented with a headache and seizure at our department. Neurological examinations were otherwise normal. On physical examination he had asymptomatic, bluish, speckled, and well-demarcated hyperpigmented macules on the left midface extraorally. A left temporal space-occupying lesion was seen on magnetic resonance imaging. The mass was hyperintense on T1-weighted images and isointense on T2-weighted images. Enhancement was shown on contrast-enhanced magnetic resonance imaging (MRI). The preoperative diagnosis was meningioma.

RESULT

Gross complete resection was performed. Pathological studies led to the diagnosis of meningeal melanocytoma World Health Organization (WHO) grade I. The patient received oncologic consultation. Because total resection of the tumor was achieved and its histopathologic grade was benign (WHO grade I), radiotherapy was not advised for the patient and he followed up every 6 months. No tumor was seen on follow-up MRI one year after surgery.

CONCLUSION

Presentation of meningeal melanocytoma in the supratentorial compartment is rare, and its combination with nevus Ota has been reported in very few cases. Although this lesion is benign, it might behave aggressively. Complete surgical resection of the lesion is the preferred therapeutic option.

Melanocytomas of the central nervous system: a clinicopathological and molecular study

BACKGROUND

Melanocytomas of the Central Nervous System (CNS) are rare and benign lesions. These slow-growing tumours can behave aggressively, with local recurrence. Various genetic aberrations occur in malignant melanomas and raise possible new therapeutic options. However, little information is available regarding these characteristic genetic alterations in melanocytomas of the CNS. This study was designed to better understand the clinicopathological and molecular features of melanocytomas.

MATERIALS AND METHODS

Twenty cases of melanocytoma were studied by light microscopy, electron microscopy and immunohistochemistry. Clinical characteristics, therapeutic options and prognosis were analysed. BRAF, NRAS and KIT gene mutations were tested by direct DNA sequencing.

RESULTS

Fourteen of twenty patients had intracranial tumours including one associated with naevus of Ota and six were spinal. Histologically, these tumours contain fusiform and epithelioid cells with little or no cellular pleomorphism and rare mitoses. Immunohistochemical and ultrastructural findings confirmed the origin of tumour cells as melanocytic. None of the melanocytomas harboured BRAF, NRAS and KIT mutations. Patients with complete resection had no tumour recurrence. Moreover, patients with incomplete tumour resection followed by radiotherapy showed a higher local control (LC) rate than incomplete resection alone (P < 0·05).

CONCLUSIONS

BRAF, NRAS and KIT mutations appear to be rare, if not completely absent in melanocytomas of the CNS. The complete resection of the tumour or incomplete resection followed by radiotherapy should be considered as better therapeutic options to reduce the tumour recurrence.

Primary cerebellopontine angle melanocytoma: review

Introduction Primary cerebellopontine angle melanocytomas (PCPAMs) are very rare. Their natural history and prognosis are not fully understood. We reviewed the literature and add a new case to analyze PCPAM's presentation, radiological features, and outcome of treatment.

Methods We performed a literature review using Medline, Embase, PubMed, and Cochrane databases. We searched for melanocytoma, melanoma, and pigmented tumors in the posterior cranial fossa and CPA to identify PCPAM. We have also searched our institution's neuro-oncology database.

Results We identified 23 PCPAM from the literature and one case of our own. The mean age at presentation was 44.4 years with slight male preponderance. PCPAM presented with cerebellopontine angle (CPA) syndrome with or without hydrocephalus. Preoperative diagnosis was difficult; they appeared hyperintense on T1 and isointense on T2 magnetic resonance imaging (MRI) and enhanced with gadolinium. However, the final diagnosis was only made by immunohistochemical examination. Total surgical resection of PCPAM was associated with prolonged survival while subtotal excision was associated with frequent recurrence.

Conclusion PCPAM are very rare and should be considered in the differential diagnosis of all CPA lesions that appear hyperintense on T1 and isointense on T2 MRI images. Patients with PCPAM should undergo total surgical resection to avoid fatal recurrences.

Primary melanocytic neoplasms of the central nervous system

Primary melanocytic neoplasms of the central nervous system (CNS) are rare lesions arising from melanocytes of the leptomeninges. They include diffuse leptomeningeal melanocytosis or melanomatosis, melanocytoma and primary malignant melanoma. We have reviewed the English literature regarding these lesions, which consists of case reports and a small number of larger case series. The presenting features, radiological, surgical and histological findings are reviewed, as are current management options and prognosis. We also present illustrative case reports of diffuse leptomeningeal melanocytosis and primary melanoma of the CNS.

Meningeal melanocytoma: clinical features and review of the literature

A case of meningeal melanocytoma in the posterior fossa of a 16-year-old male is reported. Computed tomographic and magnetic resonance imaging features are presented. Pathological investigation including light and electron microscopy, and immunohistochemical staining are discussed. Current literature is reviewed and differentiating criteria from meningioma and other pigmented tumours of the nervous system are discussed.

Thoracic intramedullary melanocytoma with long-term follow-up

Melanocytomas are tumors of the neuraxis seen predominantly in adults. The authors report a case of a thoracic intramedullary melanocytoma with long-term follow-up of 8 years postsurgery. Melanocytomas, although rare, must be included in the differential diagnosis of intramedullary spinal cord tumors.

Cerebellopontine angle meningeal melanocytoma: a rare tumor in an uncommon location

✓Meningeal melanocytomas are uncommon intracranial tumors and their occurrence at the cerebellopontine angle (CPA) is extremely rare. The authors describe the case of a 58-year-old woman who presented with a left CPA tumor; on the basis of histopathological studies after resection, a diagnosis of meningeal melanocytoma was reached. The relevant literature is reviewed.

Supratentorial meningeal melanocytoma mimicking a convexity meningioma

OBJECTIVE AND IMPORTANCE

Meningeal melanocytomas are rare benign neuro-ectodermal tumors arising from melanocytic cells in the leptomeninges. These leptomeningeal melanocytes are found at highest density underneath the brain stem and along the upper cervical spinal cord. Thus, most reported cases of meningeal melanocytomas are located in the posterior fossa and the spinal cord, respectively.

CLINICAL PRESENTATION

We report on the rare case of a 55-year-old male patient with a large supratentorial meningeal melanocytoma mimicking a convexity meningioma and a smaller, similarly dura based lesion in the posterior fossa.

INTERVENTION

Tumor control to date was achieved by surgery of the large lesion and radiosurgery of the small lesion.

CONCLUSION

Complete tumor resection may be advantageous and second or recurrent lesions may be managed by repeat surgery or stereotactic radiosurgery.

Meningeal Melanocytoma Associated with Ipsilateral Nevus of Ota Presenting as Intracerebral Hemorrhage: Case Report

OBJECTIVE AND IMPORTANCE:

The authors report a rare case of meningeal melanocytoma presenting with unconsciousness, which was caused by an intracerebral hematoma and associated with a history of ipsilateral nevus of Ota.

CLINICAL PRESENTATION:

A 75-year-old woman developed nevus of Ota in the first and second divisions of the right trigeminal nerve territory, which had been treated with a skin graft 40 years earlier. She noticed right exophthalmos but left it untreated for 2 years and then became comatose owing to orbital and intracranial tumors, the latter manifesting with hemorrhage.

INTERVENTION:

She underwent craniotomy, during which the tumor was partially removed with intracerebral hematoma. Histopathologically, the tumor was diagnosed as meningeal melanocytoma. Western blot analysis demonstrated a retained protein expression of cell cycle inhibitor p16INK4A and a high level of antiapoptotic Bcl-2 in the resected tumor.

CONCLUSION:

The combination of nevus of Ota and meningeal melanocytoma has been reported in only four cases in the literature, including the current case. This is the first case coinciding with intracerebral hemorrhage, suggesting the necessity for careful follow-up with radiological images.

Meningeal melanocytoma of the posterior fossa: case report and literature review

BACKGROUND

Meningeal melanocytomas are rare primary melanotic tumors of the leptomeninges. According to our review of the literature, just 22 cases of meningeal melanocytoma (MM) of the posterior fossa have been previously reported. Some aspects related to diagnosis, radiological appearance, histopathologic features, and management are discussed in this paper.

CASE DESCRIPTION

We describe the case of a 42-year-old female presenting with severe headache, nausea, and vomiting. Computed tomography and magnetic resonance imaging demonstrated a posterior fossa lesion that was surgically treated. Histopathologic examination showed a highly cellular melanocytic neoplasm with numerous dark pigments in the cytoplasm. Immunoperoxidase staining S-100 protein and HMB 45 demonstrated immunoreactivity for both, confirming the diagnosis of MM.

CONCLUSIONS

In conclusion, MMs are rare histologically benign tumors that can be cured by complete surgical resection alone, which should be the goal of the treatment. These lesions, although rare, should be considered in the differential diagnosis of tumors of the posterior fossa.

Primary Malignant Cerebellopontine Angle Melanoma Presenting as a Presumed Meningioma: Case Report and Review of the Literature

Primary intracranial melanomas are rare, especially in the primary cerebellopontine angle. We describe a patient with a presumed jugular foramen meningioma that was found to be of melanotic origin at surgery. We followed this 26-year-old woman with mild ataxia with serial imaging for 18 months after the initial discovery of a cerebellopontine angle extra-axial mass. She developed worsening symptoms of ataxia, dysphagia, and right-sided hearing loss. Magnetic resonance imaging showed an interval increase in size of the mass. The lesion was thought to be a meningioma with a dural tail that extended into the jugular foramen and hypoglossal canal. She underwent preoperative angiography and attempted tumor embolization, followed by resection via a transcochlear infratemporal approach. At surgery the lesion was found to be heavily pigmented. Pathological analysis was consistent with a low-grade melanoma. No primary extracranial site was identified. One year after surgery the patient remains free of systemic disease or recurrence.

Therapy of meningeal melanocytomas

BACKGROUND

Meningeal melanocytomas are rare, benign central nervous system lesions with a high probability of recurrence. To the authors' knowledge, approximately 100 cases have been reported since 1972, when the entity first was described. In the current study, four therapies were compared with regard to local control and survival to identify which is best.

METHODS

All reported cases were reviewed with regard to extent of resection, radiotherapy, local control, and survival. If published data were incomplete, the authors were contacted for additional data. Patients were categorized by therapy: complete resection (CTR), complete resection followed by radiotherapy (CTR-RT), incomplete resection (ITR), and incomplete resection followed by radiotherapy (ITR-RT). Local control and survival were calculated using the Kaplan-Meier method. A multivariate analysis was performed including age, gender, tumor location, confirmation of extent of resection, and treatment schedule.

RESULTS

A total of 89 patients were included: 46 with CTR, 3 with CTR-RT, 23 with ITR, and 17 with ITR-RT. The 5-year local control rate was 80% after CTR, 100% after CTR-RT, and 72% after ITR-RT versus 18% after ITR (P < 0.001). The 5-year survival rate was 100% after CTR, CTR-RT, and ITR-RT, respectively, versus 46% after ITR (P < 0.001). Multivariate analysis demonstrated that therapy was the only variable that affected local control and survival significantly. In 14 patients treated with ITR-RT, RT was restricted to the tumor region. The radiation dose was 30-40 grays (Gy) in 6 patients, 45-55 Gy in 7 patients, and unknown in 1 patient. The 5-year local control rate was 86% after a dose of 45-55 Gy versus 27% after a dose of 30-40 Gy (P = 0.1).

CONCLUSIONS

CTR was found to be significantly superior to ITR with regard to both local control and survival. Outcome was significantly improved by RT after ITR. Doses of 45-55 Gy appeared to be more beneficial than doses of < or = 40 Gy.

Meningeal melanocytoma: an aggressive course for a benign tumor

A 79-year-old female presented with difficulty ambulating and was found to have weakness and hyperreflexia in the lower extremities. Magnetic resonance imaging (MRI) revealed a large T8-T9 intraspinal tumor. She underwent a thoracic laminectomy, and excision of an intradural extramedullary lesion. The surgical specimen was soft, black tissue that consisted of a moderately cellular, deeply pigmented tumor. The neoplastic cells proved to be melanocytic, and were devoid of overt features of anaplasia, i.e., prominent nuclear pleomorphism, necrosis, significant mitotic activity, and high proliferation indices. Four months postoperatively, MRI demonstrated focal areas of enhancement in the conus medullaris and in the fourth ventricle, indicating leptomeningeal spread. Subsequently, the patient underwent whole brain radiation. On repeat imaging, there was nodular enhancement of the fourth ventricle and throughout the spinal cord. Despite chemotherapy and radiation therapy, the disease advanced and the patient expired. Meningeal melanocytoma is a rare, histologically benign tumor with good prognosis. However, local aggressive behavior has been recorded, especially in cases of subtotal gross resection. On a literature review, there was one case of cranial posterior fossa meningeal melanocytoma with associated lesions in both suprarenal glands and the left kidney, but there were no cases with distant metastasis. In this report, we present an unusual case of spinal meningeal melanocytoma with diffuse spread throughout the craniospinal axis that proved to be fatal.

Malignant transformation of meningeal melanocytoma: A case report

Intracranial meningeal melanocytoma is an uncommon tumor that is considered benign. We formerly reported an intracranial meningeal melanocytoma. Here we report a extremely rare case of malignant transformation of this tumor. A 49-year-old man complained of a headache. Magnetic resonance scanning revealed a mass in the left frontal region. The patient underwent gross total removal of the tomor in 1994. The histological findings showed a meningeal melanocytoma. In 1998, he underwent gamma-knife surgery for local recurrence. An additional operation was performed in 1999 became tumor growth was not stopped. The tumor was partially excised by left frontal craniotomy. Histopathological examination revealed a malignant melanoma originating from a melanocytoma. The tumor was composed of a proliferation of severely atypical melanocytoid cells with slightly irregular nuclei and prominent nucleoli, associated with necrosis and hemorrhage. Mitotic figures were encountered occasionally. After six months, he died from cerebrospinal fluid dissemination of this tumor. To our knowledge, this is the first report of malignant transformation of an intracranial meningeal melanocytoma.

Meningeal melanocytoma of the brain and oculodermal melanocytosis (nevus of Ota): case report and literature review

BACKGROUND

Meningeal melanocytomas are rare benign pigmented tumors of meningeal melanocytes. Nevus of Ota is a melanocytic pigmentation of the sclera and the skin adjacent to the eye. We report a rare case of parietal convexity meningeal melanocytoma associated with ipsilateral mucocutaneous melanosis and review the literature.

METHODS

A 17-year-old man presented with headache and blindness. There was left scalp and facial mucocutaneous melanosis. During surgery, speckled hyperpigmentation was seen in all layers of the scalp, bone, dura, and even ependyma. Pathologic examination of the tumor and scalp consisted of light microscopy and immunohistochemistry. In a literature review, the demographics (age, sex), clinical characteristics (site of lesion, duration of symptoms), therapeutic options (surgical excision, radiotherapy), and prognosis (recurrence, death, death related to the disease, and follow-up) were analyzed. For statistical analysis we used the independent sample t-test and chi(2) tests.

RESULTS

Ninety-five cases (45 intracranial and 50 spinal) of meningeal melanocytoma have been reported. The median age of patients with intracranial lesions (40 years) was significantly lower than that of patients with spinal lesions (49 years) (p = 0.016). Of the 95 patients, 57.9% were female. In the nervous system, melanocytes are more common in the infratentorial and cervical areas, but more than half of the tumors have been located in the supratentorial region and the thoracic spine. In 46 months median follow-up, tumor recurrence rate and tumor related death rate were 26.3% and 10.5%, respectively. These were not statistically significant for different therapeutic modalities. There was a trend toward shorter survival for patients who underwent subtotal tumor resection without radiotherapy compared with other groups.

CONCLUSION

The prognostic criteria, differential diagnosis, and the embryological aspects of meningeal melanocytoma are discussed with a review of the related literature.

Intracranial meningeal melanocytoma

A 59-year-old man presented with a rare intracranial meningeal melanocytoma in the left cerebellopontine angle. The patient underwent partial surgical excision and radiosurgery for successful control of the tumor. Meningeal melanocytoma is an essentially benign melanotic tumor, derived from the melanocytes of the leptomeninges, and may occur anywhere in the cranial and spinal meninges. Preoperative differential diagnosis of intracranial meningeal melanocytoma from malignant melanoma is difficult based on magnetic resonance imaging. Ultrastructural findings are essential to establish the diagnosis. The prognosis of this tumor is not always favorable with occasional local recurrence. Total resection is the best treatment, but gamma knife radiosurgery is effective for the residual tumor following partial resection.

Suprasellar melanocytoma: a case of primary radiotherapy and review of the literature

Meningeal melanocytoma is a rare benign neoplasm of the central nervous system. Approximately 50% of the tumors are located intracranially with a preference for posterior fossa. We report a new case of intracranial suprasellar melanocytoma in a 57-year-old male patient treated with primary high-dose conformal radiotherapy to 50.4 Gy. Fourty-two months subsequent to treatment the tumor is well under control without neither deterioration of clinical symptoms nor progression of gross tumor volume on MR imaging. No late sequelae of treatment have been observed. A review of the literature is presented indicating that resection of melanocytoma is the treatment of first choice hampered by a relapse rate of approximately 30% depending on resection status. The role of adjuvant radiotherapy in patiens with complete resection of melanocytoma has not yet been defined. These patients carry a risk of relapse of approximately 15%, and adjuvant irradiation is currently not recommended. Primary high-dose radiotherapy has been shown to be effective in long-term control of the neoplasm in patients where no resection of the tumor could be accomplished. In case of incomplete resection of melanocytoma, data of the literature indicate that adjuvant radiotherapy may in fact increase long-term local control of the tumor. Requirements for optimal treatment results of radiotherapy are sufficiently high doses of, at least, 50 Gy for intracranial lesions and three-dimensional treatment planning guaranting precise targeting of the tumor volume with only a low-risk of late sequalae to the surrounding tissues.

Therapeutic options for meningeal melanocytoma. Case report

Meningeal melanocytomas are uncommon lesions. They are generally considered to be benign tumors that derive from leptomeningeal melanocytes. A rare case of a metastatic spinal meningeal melanocytoma is presented. All relevant cases reported in literature since 1972, when the term "meningeal melanocytoma" was first used, were reviewed. Rates of tumor recurrence from 1 to 5 years were calculated for this rare lesion, based on published data and on additional information obtained from personal contact with most of the authors. Recurrency rates of 47 patients suitable for evaluation were correlated with the different therapeutic approaches. Complete tumor resection alone and incomplete resection alone followed by irradiation appeared to be superior to incomplete resection alone in terms of disease-free survival. Statistical significance was achieved for complete tumor resection at follow up between I and 4 years (range p = 0.010-0.050) and for incomplete resection combined with radiotherapy after 2 years (p = 0.034). Complete tumor resection should be considered the best therapeutic option, followed by incomplete resection combined with postoperative radiotherapy.

Meningeal melanocytoma of the planum sphenoidale. Case report and review of the literature

Meningeal melanocytoma is a rare benign primary melanotic tumor of the meninges, most commonly found in the spinal canal and the posterior fossa. The authors report the 19th published case of a supratentorial meningeal melanocytoma and the first reported case in which the tumor arose from the planum sphenoidale. The patient's presenting symptoms were characteristic of a large bifrontal lesion and included headaches, personality change, lethargy, and urinary and fecal incontinence. Computerized tomography and magnetic resonance imaging studies revealed an extraaxial lesion arising from the planum sphenoidale. The patient underwent successful gross total removal of the tumor without neurological sequelae. Based on the findings shown in this case report, meningeal melanocytoma should be included in the differential diagnosis of extraaxial lesions arising from the area of the planum sphenoidale.

Radiosurgery of meningeal melanocytoma

The authors present a case of meningeal melanocytoma arising from Meckel's cave. A coal-black, vascular tumor was partially removed by surgery. Histopathologically, the tumor lacked anaplastic features. Immunohistochemical studies confirmed that the tumor was of neuroectodermal origin and had low proliferating activity. The patient underwent gamma knife radiosurgery for the residual tumor, in which 25 Gy of radiation was delivered to the tumor margin. Three years after irradiation, the tumor showed marked shrinkage without complication.

Primary melanocytic neoplasms of the central nervous systems

Primary melanocytic neoplasms of the central nervous system (CNS) consist of a spectrum ranging from well-differentiated melanocytoma to its overtly malignant counterpart, melanoma. Diagnostically difficult intermediate lesions lie between these extremes. Clinicopathologic features of 33 cases were studied to define histologic appearances, diagnostic criteria, and the clinical behavior of lesions along this spectrum. Seventeen cases were well-differentiated, solitary leptomeningeal tumors classified as melanocytomas. They contained variably pigmented melanocytic cells arranged in tight nests, sheets, or fascicles. Mitotic rates ranged from zero to one per 10 high-power fields (HPFs), with most having zero per 10 HPFs. All tumors were immunoreactive for HMB-45 and S-100 protein and negative for epithelial membrane antigen. MIB-1 staining was low (<1-2%). Nuclei were regular, often with small, eosinophilic nucleoli. These lesions arose predominantly in the spinal canal (65%) in patients ranging in age from 17 to 73 years. None recurred after surgical resection. In contrast to these benign lesions, there were 13 cases with histologic and cytologic features consistent with those of malignant melanoma. These cases contained larger, cytologically atypical, pigmented tumor cells growing in loose nests or sheets, often with CNS invasion or necrosis. Some contained bizarre, pleomorphic nuclei; others were densely cellular and mitotically active, but less pleomorphic. Mitotic rates (mean, 5.7 per 10 HPFs) and MIB-1 labeling indices (mean, 8.1%) were higher than those of melanocytomas. Melanomas occurred at spinal (38%), posterior fossa (38%), and supratentorial (23%) levels in patients ranging in age from 15 to 71 years. After resection, 8 of 13 lesions recurred, with four being fatal (mean survival, 14 months). Of five totally resected melanomas, four did not recur (mean follow-up, 26 months). Three intermediate-grade melanocytic tumors could not be classified as melanocytoma or melanoma. All showed sheetlike growth patterns, microscopic CNS invasion, and occasional mitoses. MIB-1 staining ranged from 1% to 4%. One tumor recurred after 17 months; one patient was lost to follow-up after 5 months; and the third died after surgery. Although melanocytic tumors represent a spectrum of lesions, certain histopathologic features are helpful in predicting biologic behavior.

Meningeal melanocytoma: a case report and literature review

The clinicopathologic, immunocytochemical, and electron microscopic features of a case of meningeal melanocytoma arising in the phylum terminale are reported. Meningeal melanocytoma is an uncommon tumor that must be distinguished from metastatic or primary malignant melanoma, meningeal melanocytic nevi, pigmented meningioma, pigmented schwannoma or neurofibroma, and pigmented primitive neuroectodermal tumor. This is a difficult differential diagnosis that can be best archived by complementing histological examination with a selected panel of antibodies and, most important, electron microscopic study. The distinctive ultrastructural appearance of most of these lesions point to this technique as the gold standard in pigmented proliferations of the nervous system.

Spinal meningeal melanocytoma presenting with superficial siderosis of the central nervous system. Case report and review of the literature

Meningeal melanocytoma is a benign melanocytic tumor that originates most frequently from the melanocytes in the posterior fossa or along the spinal cord. This tumor generally occurs as an extraaxial mass that compresses adjacent neural structures to produce various neurological signs. The authors describe an unusual case in which a patient with a meningeal melanocytoma located at the thoracic spinal cord presented with superficial siderosis of the central nervous system (CNS). Extensive neuroradiological studies identified the presence of a spinal cord tumor, and postsurgical histological examination revealed the meningeal melanocytoma as a bleeding source. After surgery, lumbar puncture demonstrated normalization of the patient's cerebrospinal fluid; however, no neurological improvement occurred. The neurological deficits seem irreversible. Meningeal melanocytoma is biologically benign and can be cured by complete surgical resection; therefore, this tumor should be included in the differential diagnosis of pigmented lesions of the CNS. The authors reviewed 14 cases of well-documented meningeal melanocytoma in the literature and discuss the clinical, radiological, and pathological features of the present case to emphasize the importance of early diagnosis and identification of the source of bleeding in patients with superficial siderosis.

Meningeal melanocytoma. Report of a case and a historical comparison

Meningeal melanocytomas are rare tumors of the central nervous system that are found almost exclusively in the posterior fossa and spinal cord and whose natural history is poorly defined. In this report, the authors review the clinical presentation, radiological appearance, operative findings, and histological features in two cases of meningeal melanocytoma: one cranial and one spinal. Two women, aged 21 and 30 years, were admitted to the hospital 60 years apart: the first because of progressive paraplegia and the second because of slowly progressive hearing loss. The first patient had an extradural tumor that was treated by laminectomy, subtotal resection, and postoperative radiotherapy in 1936. Her symptoms recurred 16 years later and she underwent reoperation of the residual tumor, which was found to have an intradural component. The authors' patient, who presented 60 years later, underwent plain and enhanced computerized tomography and magnetic resonance imaging that demonstrated a large posterior fossa lesion indicative of either an acoustic neuroma or a meningioma. She underwent posterior fossa decompression but only partial excision of the tumor could be accomplished because vigorous bleeding limited the extent of the resection. Surgery was followed by radiotherapy. The residual tumor enlarged despite these measures and required repeated resection 6 months later. At the second operation the tumor was much less vascular, perhaps reflecting the effects of radiotherapy, and was removed almost entirely. The patient died 6 months later from an anticoagulant-related cerebellar hemorrhage. In both cases the lesions were jet black, and histological examination revealed melanin-containing hypercellular tumors with rare mitotic figures. Meningeal melanocytomas are being diagnosed with increased frequency in parallel with improvements in neuroimaging and clarification of histological features. Clinical presentation of patients with these tumors typically occurs in their fifth decade and women are affected twice as often as men. The posterior fossa lesions can mimic acoustic neuromas and meningiomas in location and radiological appearance; however, the internal auditory canal is normal. In the spine, meningeal melanocytomas present with the clinical features of myeloradiculopathy. Diagnosis is made intraoperatively from the gross, jet-black appearance of the tumor and from histological examination. Vascularity, size, and location may render complete resection unfeasible. Because of the tumor's propensity to recur, radiotherapy has been recommended but its role remains to be elucidated.

Melanocytoma of the foramen magnum

This report concerns a 66-year-old man with a melanocytoma arising at the foramen magnum. Magnetic resonance imaging disclosed a well-circumscribed tumor extending from the medulla oblongata to C1 with gadolinium enhancement. A heavily pigmented tumor located under the leptomeninges was removed surgically. Although the patient died 8 months later of renal cell carcinoma, no recurrence or metastasis of the melanocytoma was detected by radiographic examination. Microscopically, the resected tumor was composed of polygonal to spindle-shaped cells containing large amounts of melanin. The bland nuclei of the tumor cells were of uniform size. No mitotic figures were seen. The tumor cells were positively immunostained for S-100 protein and by antibody HMB-45. They were not stained using the Ki-67 (MIB-1) antibody, indicating low proliferative activity. The ultrastructural examination revealed numerous mature melanosomes and basal laminae surrounding nests of cells. The tumor was diagnosed as a melanocytoma on the bases of its microscopic features and the lack of Ki-67 immunoreactivity. The ultrastructural and immunohistochemical features of melanocytomas are distinct from those of meningiomas. It is likely that melanocytomas and melanotic schwannomas represent opposite extremes of the continuous spectrum of neuroectodermal tumors derived from the neural crest.