Pigmented lesions of the central nervous system: radiologic-pathologic correlation

Primary melanocytic tumors of the central nervous system: Report of two cases and review of literature

Background:

Primary melanocytic tumors of the central nervous system (CNS) represent only 1% of all melanomas. We report two rare cases of primary diffuse leptomeningeal melanomatosis (PDLM; case 1) and primary melanoma of the thoraco-lumbar spine (case 2).

Case Description:

In case 1, multiple cerebrospinal fluid (CSF) studies and a brain biopsy were non-diagnostic, with a biopsy of the cauda equina eventually demonstrating malignant melanomatosis. Diagnosis of primary spinal cord melanoma was more straightforward in case 2 with imaging and biopsy.

Conclusion:

PDLM and primary intramedullary spinal melanoma are rare variants of primary CNS melanoma. This report contrasts the diagnostic challenges between the two entities and alerts the neurosurgeon into considering the diagnosis with appropriate clinical presentation.

Is it a primary or metastatic melanocytic neoplasm of the central nervous system?: A molecular based approach

Primary melanocytic neoplasms of the central nervous system (CNS) are uncommon and must be distinguished from metastatic lesions as patients with metastatic disease carry a worse prognosis. Therefore, tools to aid in the diagnosis of a primary CNS melanocytic neoplasm would be of clinical utility. Primary CNS melanocytic neoplasms, including uveal melanomas have frequent mutations in GNAQ and GNA11, but are rare in cutaneous and mucosal melanomas. Additionally, primary uveal melanomas often exhibit monosomy 3 conferring an elevated risk of metastasis. We present a 63 year-old male with a melanocytic neoplasm in the thoracic spinal cord. Molecular studies revealed the tumor contained a GNAQ mutation and four-color fluorescent in situ hybridization (FISH) composed of chromosome enumeration probes for 3, 7, 17 and a locus specific probe for 9p21/CDKN2A yielded a normal result (i.e. two copies per cell), favoring a primary versus metastatic melanocytic neoplasm of the CNS. We report a case in which the combination of mutational analysis and FISH aided in identifying the origin of the neoplasm.

Encephalocraniocutaneous lipomatosis with neurocutaneous melanosis

Encephalocraniocutaneous lipomatosis is a rare neurocutaneous syndrome characterized by classical cutaneous and ocular lesions with central nervous system anomalies. We describe an infant with classical encephalocraniocutaneous lipomatosis characterized by probable naevus psiloliparus, frontal subcutaneous lipomas, ocular limbal dermoids and arachnoid cysts, and ventriculomegaly. He also had giant congenital nevus with leptomeningeal melanosis. This case represents a rare association between encephalocraniocutaneous lipomatosis and neurocutaneous melanosis.

Neurocutaneous melanocytosis

Neurocutaneous melanosis or neurocutaneous melanocytosis is a rare sporadic congenital disorder characterized by the presence of giant and/or multiple satellite congenital melanocytic nevi in the skin and benign melanocytic pigmentation of the leptomeninges. These two defining features were recognized more than a century ago. A third characteristic feature is proliferative nodules arising from giant nevi. The etiology is unknown, but neurocutaneous melanosis is considered a developmental disorder of melanocyte precursors from neural crest. The distinctive unique distribution of the congenital giant nevi that gives a "garment" appearance is also an expression of the neural crest. The neurological manifestations often appear in infancy.The special association of neurocutaneous melanosis with Dandy-Walker malformation complex may be explained by a common pathogenesis. Mortality in infancy and childhood is high.

A newborn with neurocutaneous melanocytosis and Dandy-Walker malformation

BACKGROUND

Neurocutaneous melanocytosis is a rare congenital dysplasia of the neuroectodermal melanocyte precursor cells that leads to proliferation of melanin-producing cells in the skin and leptomeninges.

PATIENT

We describe a newborn with a giant congenital melanocytic nevus on his back, buttocks, and thighs. His brain magnetic resonance imaging study revealed bilateral T1 hyperintense lesions in the cerebellum and in the amygdala, hydrocephalus, and a Blake's pouch cyst, consistent with neurocutaneous melanocytosis and Dandy-Walker malformation.

CONCLUSION

Neurocutaneous melanocytosis has a wide clinical spectrum that includes hydrocephalus, epilepsy, cranial nerve palsy, increased intracranial pressure, and sensorimotor deficits.

Atypical benign melanotic thoracic intradural schwannoma

We discuss the 8th known case of a patient who presented with an intradural intramedullary spinal melanocytic schwannoma. In this report we will discuss the hypothesis regarding the pathogenesis of the development of intradural schwannomas, the imaging modality of choice and treatment options.

Melanotic schwannoma of the cervical spine progressing with pulmonary metastasis: case report

Melanotic schwannoma (MS) is an unusual variant of nerve sheath neoplasm. Only 10% of these tumors will undergo malignant degeneration, with exceedingly rare reported metastasis. We present a 32-year-old woman with a 6-month history of cervical pain and left arm progressive weakness. Neurological examination showed a left upper limb radicular pain, with pyramidal syndrome at C5 level. The magnetic resonance imaging (MRI) study highlighted an intradural extramedullary heterogeneous mass along the spinal cord at the C4-C5 level, slightly hyperintense with T1 and hypointense with T2-weighted sequences, invading the left neural foramen. The patient underwent C3-C5 laminectomy with total resection of a black tumor. In the postoperative period, a patent deficit of shoulder abduction ensued related to the nervous section. Microscopically, compactly fascicles of spindle-shaped cells with pleomorphic and hypercromatic nuclei, dark brown intracellular pigments, as well as some mitotic figures were seen. Immunohistochemical stains for S-100, Human Melanoma Black-45 (HMB-45), and vimentin were positive, with Ki-67 Labelling Index (LI) of 15% compatible with MS. Six months after radiotherapy she presents local recurrence and lung metastatic dissemination of the MS. She underwent left pulmonary segmentectomy, followed by chemotherapy and radiosurgery. The patient developed a febrile neutropenia and worsening of general status, and died after 3 months due to respiratory complications. MS are rare tumors with potential for local recurrence and distal metastasis. Complete surgical resection remains as the treatment of choice, once the uncommon cases with malignant progression shows low response to chemo and radiotherapy.

Bifocal extra- and intradural melanocytoma of the spine: case report and literature review

BACKGROUND

Spinal melanocytoma is one of the most infrequent space-occupying lesions of the central nervous system. To the best of our knowledge, this is the first report of primary bifocal intradural melanocytoma of heterogeneous pathological grade to date.

CASE DESCRIPTION

We report the case of a 43-year old patient with primary bifocal melanocytoma, clinically and radiologically resembling benign schwannoma. The patient presented with myeloradiculopathy of the left C3 dermatome. Magnetic resonance imaging of the upper spine revealed two space-occupying lesions with paraspinal extension, initially diagnosed as neurofibroma. Definitive histopathological classification of both lesions was melanocytoma. Both tumours were only partially removed due to adherence to surrounding structures. The patient underwent stereotactic external beam irradiation (EBR). Follow-up at 1 year after surgery revealed no recurrence and the patient remained free of symptoms. The clinical, radiological and pathological features of this rare tumour entity are presented and the available literature is reviewed.

CONCLUSIONS

Intradural melanocytoma, although exceedingly rare, requires a thorough work-up to exclude malignant melanoma. With only two previous reports of multifocal melanocytoma published in the literature, standard therapy has not yet been established and complete surgical removal remains the modality of choice. Patients should be closely monitored to detect local recurrence or malignant degeneration. EBR may be considered in cases where total excision is not achievable and reduces risk of local recurrences.

F-18 fluorodeoxyglucose PET/CT and post hoc PET/MRI in a case of primary meningeal melanomatosis

Primary meningeal melanomatosis is a rare, aggressive variant of primary malignant melanoma of the central nervous system, which arises from melanocytes within the leptomeninges and carries a poor prognosis. We report a case of primary meningeal melanomatosis in a 17-year-old man, which was diagnosed with (18)F-fluorodeoxyglucose (F-18 FDG) PET/CT, and post hoc F-18 FDG PET/MRI fusion images. Whole-body F-18 FDG PET/CT was helpful in ruling out the extracranial origin of melanoma lesions, and in assessing the therapeutic response. Post hoc PET/MRI fusion images facilitated the correlation between PET and MRI images and demonstrated the hypermetabolic lesions more accurately than the unenhanced PET/CT images. Whole body F-18 FDG PET/CT and post hoc PET/MRI images might help clinicians determine the best therapeutic strategy for patients with primary meningeal melanomatosis.

Intracranial melanocytic meningeal tumours and melanosis oculi: case report and literature review

Background

Melanocytic meningeal tumours are rare extra-axial neoplasms of the nervous system, with only three reported cases in the cavernous sinus. Herein we describe for the first time the association of ocular melanosis and multiple intracranial melanocytic meningeal tumours, with the presenting lesion being in the cavernous sinus. The importance of this association is discussed together with the diagnostic and therapeutic challenges of the case.

Case presentation

A 20-year-old man presented with a left sixth cranial nerve deficit; general examination documented only congenital melanosis of the homolateral eye. MRI examination showed a space occupying lesion in the left cavernous sinus, which was followed conservatively for 2 years, until a new space occupying lesion was evident at the level of the right frontal convexity: both lesions presented with neuroradiological characteristics suggestive of melanin content.

The frontal convexity lesion was removed: intraoperatively the dura was markedly and diffusely melanotic. Histological examination documented a melanocytic meningeal tumour, with a proliferative index of 3 %. The patient underwent 3D-Conformal Radiation Therapy on the lesion of the cavernous sinus (total dose 5040 cGy), with initial tumour reduction. Three years later, due to a symptomatic growth, he underwent partial removal of the lesion in the cavernous sinus. Histological examination was unchanged. He then received adjuvant Temozolomide with Low Dose Fractionated Radiation Therapy (LD-FRT). Due to further disease progression cisplatin plus fotemustine were administered, concomitant with LD-FRT: after two cycles MRI documented significant disease regression. After a period of apparent disease control, the patient presented with persistent cough and evidence of multiple thoracic metastases, which lead to his death, seven years after presentation.

Conclusions

Intracranial melanocytic meningeal tumours are challenging lesions, both from a diagnostic and therapeutic point of view; though rare, the possible association with ocular melanosis should be recognized and might facilitate an early diagnosis. Surgery remains the best possible option when feasible. In the event of partial resection, this “benign” disease might be clinically aggressive.

Stable Neurocutaneous Melanosis in a Ten-Year-Old Boy with Controlled Partial-Complex Seizures

Neurocutaneous melanosis (NCM) is a rare neuroectodermal dysplasia that includes both central nervous system (CNS) and integumentary melanocytic abnormalities. NCM can present with varied clinical and imaging findings, classically presenting with large melanocytic nevi involving the posterior axial trunk region. We describe a case with predominant small non-scalp and non posterior axial-trunk nevi, which nevertheless demonstrated typical CNS imaging findings. Our case clinically presented with epilepsy that was controlled by medical treatment. The patient also demonstrated motor developmental delay, and an otherwise stable course.

Dumbbell-shaped nonpsammomatous malignant melanotic schwannoma of the cervical spinal root

BACKGROUND CONTEXT

Melanotic schwannoma is a very rare tumor of Schwann cell origin, which can develop in various locations, similar to conventional schwannoma. This tumor has a malignant potential and therefore careful therapy is required.

PURPOSE

To describe a case of melanotic schwannoma with a histopathologically and clinically malignant behavior.

STUDY DESIGN

Case report.

METHODS

A 64-year-old man presented with sensory changes in his arm and gait disturbance. Magnetic resonance imaging revealed a dumbbell-shaped tumor at the left C7 spinal root, which was hyperintense on T1-weighted images and generally hypointense on T2-weighted images in comparison with conventional schwannoma; however, the peripheral zone was relatively hyperintense, and the central zone was hypointense like a target sign.

RESULTS

The tumor was partially resected and diagnosed to be nonpsammomatous malignant melanotic schwannoma. The patient experienced local recurrence and metastases to the bone and lung and finally developed quadriplegia. Radiation therapy failed to palliate the symptoms.

CONCLUSIONS

Some melanotic schwannomas present with an aggressive behavior, which thus leads to poor prognosis. We should therefore be familiar with its characteristic clinical imaging and pathologic findings to provide a correct diagnosis and appropriate treatment for such patients.

MR imaging findings of the intraspinal meningeal melanocytoma: correlation with histopathologic findings

Our aim was to better understand and improve the accuracy of the preoperative diagnosis of intraspinal MM by a combined analysis of MR imaging and pathologic findings. All 5 patients had undergone unenhanced and contrast-enhanced MR imaging examinations. All tumor samples had immunohistochemical reactions to HMB-45, vimentin, S-100, EMA, and Leu-7 antibodies. All 5 cases were located in the intradural extramedullary compartment. Two cases had multifocal lesions, and 3 cases were solitary. Two cases showed homogeneously strong enhancement, and 3 cases showed moderate enhancement on contrast-enhanced T1WI. The tumor cells had positive reactions to HMB-45, vimentin, and S-100 antibodies. MR imaging plays an important role in the detection and diagnosis of intraspinal MM. Final diagnosis should be based on histopathology and IHC examinations.

[New aspects of congenital melanocytic nevi]

In recent years, prospective studies with increasing patient numbers have been published on the subject of congenital melanocytic nevi (CMN) and neurocutaneous melanocytosis (NCM). Moreover, medical experts and patient support groups have intensified their collaboration. This article summarizes current aspects of pathogenesis, clinical features, and therapy of CMN and NCM.

Primary leptomeningeal melanocytosis in a 10-year-old girl: a challenging diagnosis with a poor prognosis

Primary leptomeningeal melanocytosis is rarely encountered in the pediatric population. Despite being considered a nonmalignant condition, it uniformly carries a poor prognosis given the ineluctable progression of meningeal infiltration. The case of a previously healthy 10-year-old girl who was first thought to suffer from recurrent hemiplegic migraine is reported. She later developed insidious subacute hydrocephalus. Meningeal biopsy performed during shunt insertion demonstrated an unexpectedly large number of melanocytes consistent with meningeal melanocytosis. Subsequently, the child developed recurrent shunt dysfunction and showed evidence of malignant transformation. The steps to reaching the proper diagnosis are discussed, and the current literature on this rare clinical entity as well as on related central nervous system melanocytic lesions that can occur in the pediatric population is reviewed.