Primary leptomeningeal melanoma. Diagnosis by ultrastructural cytology of cerebrospinal fluid and cranial computed tomography

Primary Diffuse Leptomeningeal Melanomatosis: Case Report and Review of the Literature

BACKGROUND

Primary diffuse leptomeningeal melanomatosis (PDLM) is an extremely rare pathologic condition that can mimic several other neurologic disease states.

METHODS

We report a rare case of PDLM without evidence of a primary focus. In addition, we performed a comprehensive review of the literature to describe all previously reported cases of PDLM.

RESULTS

In the reported case, making the diagnosis of PDLM was difficult. A brain and frontal dural biopsy was nondiagnostic. Computed tomography of the chest, abdomen, and pelvis did not show any distinct solitary mass. After a positron emission tomography scan was performed that showed lumbar sacral enhancement, lumbar dorsal rootlet biopsy was initiated, which was diagnostic of PDLM. Our literature review found 32 previously reported cases of PDLM. Sixteen cases (48.5%) had a distinct focus or mass discovered on imaging workup. The reported case was the seventeenth reported case of PDLM without a distinct focus or mass found on imaging workup.

CONCLUSIONS

PDLM is an extremely rare disease, and diagnosis is difficult because of nonspecific clinical, radiographic, and laboratory findings. In approximately half of cases, no distinct mass is shown on imaging workup, which may further complicate diagnosis. PDLM should be on the differential diagnosis for cases of diffuse dural enhancement. Neurosurgical intervention is often limited to ventriculoperitoneal shunting for increased intracranial pressure and dural and cranial biopsy to obtain diagnosis. If the initial biopsy is nondiagnostic, hypermetabolic activity as seen on positron emission tomography may be helpful to find an alternative biopsy site.

Leptomeningeal metastasis

Leptomeningeal metastasis (LM) results from dissemination of cancer cells to both the leptomeninges (pia and arachnoid) and cerebrospinal fluid (CSF) compartment. Breast cancer, lung cancer, and melanoma are the most common solid tumors that cause LM. Recent approval of more active anticancer therapies has resulted in improvement in survival that is partly responsible for an increased incidence of LM. Neurologic deficits, once manifest, are mostly irreversible, and often have a significant impact on patient quality of life. LM-directed therapy is based on symptom palliation, circumscribed use of neurosurgery, limited field radiotherapy, intra-CSF and systemic therapies. Novel methods of detecting LM include detection of CSF circulating tumor cells and tumor cell-free DNA. A recent international guideline for a standardization of response assessment in LM may improve cross-trial comparisons as well as within-trial evaluation of treatment. An increasing number of retrospective studies suggest that molecular-targeted therapy, such as EGFR and ALK inhibitors in lung cancer, trastuzumab in HER2+ breast cancer, and BRAF inhibitors in melanoma, may be effective as part of the multidisciplinary management of LM. Prospective randomized trials with standardized response assessment are needed to further validate these preliminary findings.

A rare case of leptomeningeal carcinomatosis in a patient with uveal melanoma: case report and review of literature

Uveal melanoma is a rare subtype of melanoma, accounting for only 3-5% of all melanoma cases in the USA. Although fewer than 4% of uveal melanoma patients present with metastasis at diagnosis, approximately half will develop metastasis, more than 90% of which disseminate to the liver. Infrequently, a number of malignancies can lead to leptomeningeal metastases, a devastating and terminal complication. In this case report, we present an exceedingly rare case of a patient with uveal melanoma who developed leptomeningeal carcinomatosis as the sole site of metastasis. After conventional methods to diagnose leptomeningeal carcinomatosis fell short, a diagnosis was confirmed on the basis of identification and genomic analysis of melanoma circulating tumor cells in the cerebrospinal fluid.

Primary leptomeningeal melanoma of the cervical spine mimicking a meningioma-a case report

Background and Importance Primary leptomeningeal melanoma (PLM) is highly malignant and exceedingly rare. Due to its rarity, diagnostic and treatment paradigms have been slow to evolve. We report the first case of a PLM that mimics a cervical spine meningioma and then discuss the current clinical, radiologic, and pathologic diagnostic methodologies as well as expected outcomes related to this disease. Clinical Presentation A 54-year-old woman presented a dural-based extramedullary solid mass ventral to the C2-C3 spinal cord causing spinal cord compression without cord signal changes, characteristic of meningioma. Intraoperative microscopic inspection revealed numerous black spots littering the surface of the dura; the tumor itself was yellow in appearance and had a soft consistency. Pathologic analysis of the specimen revealed a malignant melanin-containing tumor. No primary site was found, so a diagnosis of primary leptomeningeal melanoma was made, and the patient subsequently received interferon therapy. To date (2 years postoperatively), no local or systemic recurrence of the tumor has been identified. Conclusion As with most rare tumors, case reports constitute the vast majority of references to PLM. Only an increased awareness and an extensive report of each individual case can help diagnose and clarify the nature of PLM. Clinicians need to be aware of such malignant conditions when diagnosing benign tumoral lesions of the spine such as meningiomas.

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.

Leptomeningeal metastases from solid malignancy: a review

Leptomeningeal metastases (LMM) consist of diffuse involvement of the leptomeninges by infiltrating cancer cells. In solid tumors, the most frequent primary sites are lung and breast cancers, two tumors where the incidence of LMM is apparently increasing. Careful neurological examination is required to demonstrate multifocal involvement of the central nervous system (CNS), cranial nerves, and spinal roots, which constitute the clinical hallmark of the disease. Cerebro-spinal fluid (CSF) analysis is almost always abnormal but only a positive cytology or demonstration of intrathecal synthesis of tumor markers is diagnostic. T1-weighted gadolinium-enhanced sequence of the entire neuraxis (brain and spine) plays an important role in supporting the diagnosis, demonstrating the involved sites and guiding treatment. Radionuclide CSF flow studies detect CSF compartmentalization and are useful for treatment planning. Standard therapy relies mainly on focal irradiation and intrathecal or systemic chemotherapy. Studies using other therapeutic approaches such as new biological or cytotoxic compounds are ongoing. The overall prognosis remains grim and quality of life should remain the priority when deciding which treatment option to apply. However, a sub-group of patients, tentatively defined here, may benefit from an aggressive treatment.

Cognitive decline in an elderly hospitalized patient with primary leptomeningeal melanomatosis

Delirium is one of the most common disorders in hospitalized patients. The authors present the case of an elderly male patient with postoperative cognitive decline that did not resolve with the conventional treatment. The diagnosis was only established on autopsy. A 75-year-old man was evaluated after a fall. Initial evaluation revealed voluntary guarding in the right epigastric region, and free air was detected under the right hemidiaphragm on abdominal radiography. An exploratory laparotomy revealed a perforation that had apparently sealed off. After surgery, he had initial improvement toward baseline; however, after several days, his postoperative course was complicated by a progressive deterioration in mental status, recurrent seizures, and aspiration pneumonia. Computed tomographic scan of the brain showed communicating hydrocephalus. Examination of the cerebrospinal fluid revealed an elevated opening pressure and elevated protein. His mental status continued to deteriorate, and he died. Autopsy revealed the pathologic diagnosis of primary leptomeningeal melanomatosis.

Primary melanoma of Meckel's cave: case report

We present a case of trigeminal neuralgia with cranial normal magnetic resonance image (MRI) and computed tomography. The pain was not relieved by carbamazepine and microvascular decompression surgery was done. After two months the pain was similar to the condition before surgery. At this time, MRI showed an expansive lesion in Meckel's cave that was treated with radical resection by extra-dural approach. The pathologic examination revealed a primary melanoma. The follow-up after six months did not show abnormalities.

Primary leptomeningeal melanoma in a child

Primary malignant melanoma of the leptomeninges is a rare and aggressive tumor in children and accounts for less than 1% of all pediatric malignancies. Usually its symptoms include raised intracraneal pressure resulting from hydrocephalus secondary to tumoral obliteration of basal cisterns, but the passage of time from the initial symptomatology to diagnosis is frequently delayed. A 7-year-old male with primary leptomeningeal melanoma is reported. At the beginning, he presented ataxia and dysarthria followed by symptoms of raised intracranial pressure, complex partial seizures, progressive loss of consciousness, and coma. Cerebrospinal fluid analysis demonstrated raised opening pressure, normal glucose, and increased protein concentration, but malignant melanoma cells were not found. Magnetic resonance imaging scans depicted bright signals in the subarachnoid spaces on T(1) images and gadolinium-enhanced focal lesions. Cerebral biopsy was proposed, but it was not authorized. Definitive diagnosis was thus made by pathologic postmortem examination.

Cerebrospinal fluid immunocytochemical analysis and neuroimaging in the diagnosis of primary leptomeningeal melanoma. Case report

A 20-year-old man presented with slowly progressing symptoms indicative of increased intracranial pressure. Two weeks later he underwent surgery for placement of a ventriculoperitoneal shunt. Cytological examination of the patient's cerebrospinal fluid (CSF) revealed atypical cells that contained no detectable melanin deposits, but proved to be immunocytochemically positive for monoclonal antibodies to melanocytic cells (HMB-45) and S-100 protein. Dermatological and ophthalmological examinations failed to demonstrate any abnormalities. On the basis of these findings, a diagnosis of primary leptomeningeal melanoma was made. Gadolinium-enhanced magnetic resonance (MR) images of the brain and spinal regions obtained 2 months after admission demonstrated typical widespread leptomeningeal enhancement. Results of technetium-99m-hexakis (2-methoxyisobutyl isonitrile) single-photon emission computerized tomography (99mTc-MIBI SPECT) scanning revealed intense uptake of the isotope in the leptomeningeal regions and some cisterns. The patient's condition progressively worsened and he died 5 months after admission. The diagnosis was confirmed at autopsy. Immunocytochemical analysis of CSF performed using HMB-45 and S-100 protein antibodies is important for the diagnosis of leptomeningeal melanoma because of the test's simplicity, high specificity, and sensitivity. Gadolinium-enhanced MR imaging is used to demonstrate the extent of the leptomeningeal melanoma. An additional and supplemental neuroimaging modality, 99mTc-MIBI SPECT scanning has good potential for the detection and diagnosis of leptomeningeal melanoma.

Meningeal metastases: clinical aspects and diagnosis

The authors review the clinical and diagnostic aspects involved in leptomeningeal disease due to solid tumours, leukaemias and lymphomas. The importance of the combination of clinical findings with cerebral spinal fluid (CSF) examination and imaging studies in making an early diagnosis is underlined. The raising prevalence of this complication of systemic cancer deserves specific attention on the part of neurologists involved in consultation liason with general medicine and oncology.

[Cerebrospinal fluid in the diagnosis of cerebro-meningeal metastasis from malignant melanoma arising from giant congenital melanocytic nevus: case report]

We describe the case of a 28-year-old man with a giant congenital melanocytic nevus (GCMN) with malignant transformation to melanoma and metastasis on the central nervous system (CNS). We also make a summary of the pathological features from both lesions (GCMN and Melanoma), the occurrence of malignancy of GCMN, the organs more frequently involved with metastatic melanoma--with emphasis to involvement of CNS--just as the factors that cause malignant transformation of GCMN; the methods to diagnose metastases in CNS--emphasizing the importance of cerebrospinal fluid--and some therapeutical modalities for the metastatic melanoma in CNS.

Spinal meningeal melanocytoma. Case report and analysis of diagnostic criteria

A case of cervical juxtamedullary meningeal melanocytoma is presented along with results of careful neuroradiological and pathological examinations. The authors review the previous literature and discuss the problems related to the intriguing diagnosis of this very rare entity. CT and MRI show variable appearances due to different degrees of melanization and do not reliably allow us to distinguish meningeal melanocytomas from other pigmented tumors. Pathological examination of the tumor is critical for diagnosis, but it absolutely must comprise electron microscopy and immunohistochemistry. Immunohistochemical and ultrastructural criteria are thus proposed to distinguish meningeal melanocytoma from pigmented meningioma or schwannoma and malignant melanoma (primary or secondary).

Primary leptomeningeal melanoma simulating a meningioma

A surgically confirmed primary leptomeningeal malignant melanoma (PLMM) discovered at the parietal region is reported in a 72-year-old male. He developed progressive right hemiparesis and speech disorders caused by a parietal large mass that simulated a growing meningioma. A well-defined, dark-black tumor was removed completely and was histopathologically diagnosed as a malignant melanoma. No melanomas were detected by systemic clinical and radiological examination, including dermatological and ophthalmologic examinations. Follow-up examination 18 months postoperatively showed no evidence of recurrence of the tumor. The patient gradually became bedridden probably because of decreased general activity possibly due to brain atrophy and died of cardiac failure without any evidence of recurrence. Because of the absence of other systemic localizations, we consider this melanoma as primary. A favorable outcome was obtained by surgical treatment alone.

Neurocutaneous melanosis. Case report and a brief review

Neurocutaneous melanosis is a rare congenital syndrome characterised by large or numerous congenital pigmented naevi and excessive proliferation of melanin-containing cells in the leptomeninges. The process is diffuse or multifocal, and has a tendency to infiltrate the neural tissue and the cerebrospinal cord; remote metastases may occur. There is usually histological evidence of malignancy (cellular pleomorphism and mitotic activity). Involvement of the basal cisterns is apt to cause internal hydrocephalus, and the prognosis is grave even when there is no histological evidence of malignancy. We present the case history and necropsy findings of a baby boy with neurocutaneous melanosis, followed by a brief review.

Diffuse leptomeningeal melanomatosis of the spinal cord: a case report

A rare case of diffuse leptomeningeal melanosis presenting with symptoms of spinal cord compression due to the presence of anterolateral arachnoid cyst and treated with Spetzler's drainage system is reported. The diagnosis of diffuse melanosis of the leptomeninges is rarely possible during life. In the present case MRI was of great help in the definition of the limits of the pathological process and the presence of the anterior compressing cyst. After laminectomy and a biopsy of the pathological tissue which achieved the histological diagnosis, an external drainage was inserted to reduce the cyst extension and to exclude the presence of melanocytes in the cystic fluid before a peritoneal shunt was placed. At 8th month of follow-up the patient is doing well with a dramatic reduction of symptoms and a significant reduction of spinal cord compression. The diagnostic role of MRI and the relationship between leptomeningeal melanosis and arachnoid cyst are discussed.

Meningeal melanocytoma of the C8 nerve root: case report

A case of a meningeal melanocytoma involving the C8 nerve root is presented. The clinical symptoms and the radiological investigations resembled a neurinoma of the spinal nerve root. Intraoperatively the tumor was seen to be firmly attached to the dural covering of the dorsal nerve root. By using microsurgical technique, complete removal of the tumor with preservation of the ventral nerve root was accomplished. Histological examination revealed a typical meningeal melanocytoma as described by Limas and Tio in 1972. Ten additional cases of previously reported spinal meningeal melanocytomas are reviewed. The importance of differentiating this benign lesion from meningeal malignant pigmented tumors is stressed.

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.

Meningeal malignant melanoma in a child: immunocytological diagnosis

A 10 year old boy, who was thought to have had a traumatic intracranial hemorrhage, was transferred to our Children's Medical Center. In spite of conservative treatment, he developed dysarthria, systemic convulsions, unconsciousness, quadriplegia, and consecutive paralysis of the cranial nerves. Magnetic resonance imaging scans demonstrated areas of increased signal intensity around the brain stem. The cerebrospinal fluid (CSF) contained a few large cells with abundant melanin-like granules, and numerous bizarre cells. The latter were considered to be malignant melanoma cells on immunocytological examination. Chemotherapy with dimethyltriazenoimidazole carboxamide (DTIC) and interferon beta (IFN-beta) was ineffective and he expired. Autopsy revealed diffuse infiltration of malignant melanoma cells into the meninges. We think that immunocytological examination of CSF is advisable for correct and rapid diagnosis.

Amelanotic leptomeningeal melanoblastosis. Case report

Leptomeningeal melanoblastosis is a rare phakomatosis; the amelanotic variant has not till now been described. In this paper we report the case of a young man suffering from amelanotic leptomeningeal melanoblastosis manifested as medullary syndrome and secondary intracranial hypertension. The diagnosis of leptomeningeal melanoblastosis was hypothesized on the basis of CSF and neuroradiological findings and it was finally confirmed by the histopathology.

Balloon cell melanoma mimicking clear cell carcinoma

Balloon cells may occur in both benign nevi and malignant melanomas. Sometimes they dominate the histological appearance and cause difficulties in biopsy interpretation. There are no specific clinical characteristics. We report a metastatic balloon cell melanoma where the primary tumour was not identified and the histological appearance mimicked that of a clear cell renal carcinoma.

Meningeal melanocytoma. Report of a case and review of the literature

A primary localized, partly encapsulated melanotic tumour broadly attached to the occipital dura and tentorium was removed from a 27 year-old woman. It recurred almost four years later in the posterior fossa and was resected again. Although grossly resembling a meningioma, the tumour lacked the histological, immunocytochemical and ultrastructural features of meningiomas and was characterized by the presence of numerous melanosomes and premelanosomes in the cytoplasm of tumour cells and macrophages and was, therefore, classified as "meningeal melanocytoma". The clinical and pathological features of this and 15 other cases in the literature are reviewed. The neoplasm, mainly occurring in the posterior cranial fossa and spinal canal, may cause neurological deficits through expanding, but non-invasive growth. Its biological behaviour is variable, and recurrence may occur after incomplete resection, but transition into malignant melanoma has not been observed. Total resection of this rare pigmented tumour arising from the pial melanocytes is recommended.

Congenital neurocutaneous melanosis with metastatic orbital malignant melanoma

Proptosis and ptosis, caused by a large orbital mass that was excised and determined to be malignant melanoma, developed in a 4-year-old girl with congenital neurocutaneous melanosis (multiple large or giant cutaneous nevi associated with abnormal leptomeningeal pigmentation). Shortly thereafter, the patient had evidence suggestive of systemic metastases and died. The orbital tumor was likely metastatic from a primary meningeal melanoma. Other possible sources of metastatic tumor are discussed. It is unlikely that this was a primary orbital melanoma because the patient had no clinical or pathologic manifestations of pre-existing oculocutaneous melanosis, orbital melanosis, or orbital blue nevus.

Melanocytic precursors of cutaneous melanoma. Estimated risks and guidelines for management

There are several recognizable melanocytic precursors of cutaneous melanoma. These precursors include lentigo maligna, dysplastic melanocytic nevi, congenital nevi (of any size), and darkly pigmented lesions of acral surfaces and mucous membranes. Lentigo maligna is an uncommon melanocytic dysplasia, present in 3 per 1000 individuals over the age of 50 years and accounting for 4 percent of all cutaneous melanomas. Dysplastic melanocytic nevi are present in 2 per cent of white adults, and may account for at least a fifth of cases of cutaneous melanoma. Congenital nevomelanocytic nevi are present in 1 per cent of newborns; the vast majority of congenital nevi are smaller than 3 to 4 cm in diameter, while very large congenital nevi are present in 1 in 20,000 to 1 in 500,000 newborns. Very large congenital nevi account for less than 0.1 percent of cutaneous melanomas, whereas small varieties of congenital nevi may account for 15 percent of cutaneous melanomas. If individuals with lentigo maligna live long enough, possibly a third to a half are said to develop melanoma. This figure may be biased high. Persons with dysplastic melanocytic nevi in the familial melanoma setting have an estimated lifetime risk of developing melanoma approaching 100 per cent. Persons with dysplastic melanocytic nevi in other settings may have a lifetime melanoma risk of 18 per cent. Persons with congenital nevi of any size may have a lifetime melanoma risk of at least 5 per cent. Early recognition of these precursor melanocytic tumors, particularly in high-risk individuals (i.e., those with a personal or family history of melanoma), and careful photographic follow-up or prophylactic excision of these lesions may be the most effective means of reducing the morbidity and mortality of cutaneous melanoma. The impact of routine screening and excision of presumed melanoma precursors is unknown. Clinical judgment is required to balance the theoretical risk of melanoma associated with a given precursor and the known risks of surgery and anesthesia for a given individual. It must be kept in mind that the vast majority of acquired melanocytic nevi in adults are harmless. Probably even the majority of dysplastic nevi and small congenital nevi will remain unchanged throughout life. The simple recognition of the existence of melanoma precursors will heighten suspicion for these lesions and raise awareness of the earliest signs of malignant change.(ABSTRACT TRUNCATED AT 400 WORDS)

Metastatic melanoma of the brain after spontaneous regression of the primary

A 37-year-old man is described who presented with a large cerebral mass which proved to be a metastasis from a malignant melanoma. The primary tumour was most probably located on the scalp and regressed completely after trivial traumatization one year prior to CNS involvement.