Multiple melanotic schwannoma

Sporadic spinal psammomatous malignant melanotic nerve sheath tumor: A case report and literature review

Background

Sporadic Spinal Psammomatous Malignant Melanotic Nerve Sheath Tumor (SSP-MMNST) is a rare subgroup of peripheral nerve sheath tumors arising along the spine. Only a few reports of SSP-MMNST have been described. In this paper, we review the literature on SSP-MMNST focusing on clinical, and diagnostic features, as well as investigating possible pathogenetic mechanisms to better implement therapeutic strategies. We also report an illustrative case of a young female presenting with cervicobrachial pain due to two SSP-MMNSTs arising from C5-6 right spinal roots.

Case description

We report a case of a 28-year-old woman presenting with right arm weakness and dysesthesia. Clinical examination and neuroimaging were performed, and, following surgical removal of both lesions, a histological diagnosis of SSP-MMNST was obtained.

Results

The literature review identified 21 eligible studies assessing 23 patients with SSP-MMNST, with a mean onset age of 41 years and a slight male gender preference. The lumbar district was the most involved spinal segment. Gross-total resection (GTR) was the treatment of choice in all amenable cases, followed in selected cases with residual tumor by adjuvant radiotherapy or chemotherapy. The metastatic and recurrence rates were 31.58% and 36.8%, respectively.

Conclusion

Differently from common schwannomas, MMNST represents a rare disease with known recurrence and metastatization propensity. As reported in our review, SSP-MMNST has a greater recurrence rate when compared to other forms of spinal MMNST, raising questions about the greater aggressiveness of the former. We also found that residual disease is related to a higher risk of systemic disease spreading. This metastatic potential, usually associated with primary lumbar localization, is characterized by a slight male prevalence. Indeed, whenever GTR is unachievable, considering the higher recurrence rate, adjuvant radiation therapy should be taken into consideration.

Extramedullary malignant melanotic schwannoma of the spine: Case report and an up to date systematic review of the literature

BACKGROUND

Melanotic schwannoma is a rare variant of schwannoma. Extramedullary melanotic schwannoma originates in the vicinity of nerve roots mimicking other intervertebral disc disorders. Therefore, T1 and T2-weighted MRI sequences become an essential tool for diagnosis. Aside from case reports, no large studies exist to provide consensus on the signal intensities in T1 and T2-weighted MR imaging. Moreover, no clear evidence is available to delineate prognosis. Here, a case report is presented together with a subsequent systematic review of the literature regarding this rare entity.

CASE DESCRIPTION

A 45-year old female presented with a one-year history of insidious onset of neck pain and paraesthesia. Magnetic resonance imaging confirmed an extramedullary lesion along the C6 nerve root with T1-weighted hyperintensity and T2-weighted hypointensity. Despite two surgical decompressions and adjuvant immunotherapy, the patient unfortunately passed away due to metastatic progression.

DISCUSSION

According to the systematic review conducted, in over half of the cases of extramedullary melanotic schwannoma, there is local reoccurrence and/or distal metastasis. Moreover, in 64.7% and 70.6% of the cases, the T1-weighted image of the lesion appears hyperintense and hypointense on a T2-weighted image, respectively. It is an aggressive variant of schwannoma, one of the most commonly observed extramedullary tumours presenting to neurosurgical practice.

CONCLUSION

Our results highlight that specific T1 and T2-weighted imaging findings can provide valuable information, enabling early suspicion, influencing the surgical aims and strategy and the timely commencement of relevant immunotherapy. Considering the poor prognosis, early adjuvant therapy with other modalities should be considered.

Thoracic extradural malignant melanoma with unknown primary

Primary extradural spinal melanoma is a very rare lesion. Here, we report a thoracic extradural malignant melanoma in a 77-year-old male. MRI showed a dorsal spinal extradural tumour at the T6–T8 level. The tumour showed hyperintensity on T1W imaging and mixed hypointensity and hyperintensity on T2W imaging. Gadolinium-enhanced MRI showed high enhancement on the lesion. Information on imaging findings for extradural spinal melanoma appears very limited. We discuss the MRI findings from this case, which can be considered typical of extradural spinal melanoma and review the literature.

Malignant Melanotic Schwannian Tumor Presenting with Spinal Cord Infarction Due to Occlusion of the Artery of Adamkiewicz: Case Report and Review of the Literature

BACKGROUND

Malignant melanotic schwannian tumors (MMSTs) are rare peripheral nerve sheath tumors that typically exhibit benign clinical presentation and histopathology but malignant long-term behavior.

CASE DESCRIPTION

We report a case of a 22-year-old male with a T9-11 MMST who presented with acute paraplegia and complete loss of sacral function. Despite emergent decompression, he did not recover motor, sensory or bladder function, although bowel function did normalize.

CONCLUSIONS

The anatomic location and rapid presentation of permanent deficits are suggestive of infarction of the spinal cord supplied by the artery of Adamkiewicz, a rare presentation of this disorder and of spinal schwannomas in general.

Intracranial melanotic schwannomas: a rare variant with unusual adherent features

Intracranial melanotic schwannomas (IMSch) are extremely rare nerve sheath tumors with features of Schwann cells that produce melanin. After a thorough review of the available literature since 1967, we report not only the 20th case of IMSch but a comprehensive modern-era analysis of radiographic and histological key-points to be considered when diagnosing and treating patients with this rare known entity. This is the case of a 43 years-old woman who presented with severe headaches 9 years ago (2008). At that time, MRI of the brain showed a 1.5 × 1.4 cm lesion at the level of the left cerebellar peduncle without any evidence of edema, mass effect or hydrocephalus. Given that the patient was neurologically intact, a conservative management with serial MRIs was recommended. Patient stopped following up due to the absence of symptoms. Over the course of the past year, patient noted mild left sided hearing loss and facial weakness, as well as some balance instability that progressed over the last 3 months. Given the presentation and progression of these signs and symptoms, a new MRI was performed in which considerable growth of the lesion was identified, measuring 2.5 × 2.8 × 2.6 cm with mass effect on the pons and the inferior fourth ventricle. She underwent a far lateral approach without a C1 hemilaminectomy for the resection of this lesion. Final pathology was consistent with a non-psammomatous melanotic schwannoma (NPMS) with areas of necrosis. Besides this case, only two other cases of IMSch with findings of necrosis have been reported in the literature, all of them reporting a subtotal resection. Evaluation of all previously reported cases of IMSch shows a male prevalence with a 1.6:1 male to female ratio. IMSch is radiographically T2 hypointense and can be differentiated from Schwannomas that are classically T2 hyperintense. In this case, only a subtotal resection was feasible due to the tumor's overwhelming inherent attachment to vital structures such as cranial nerves (CN), brainstem, and vasculature. While MSch is considered histologically benign, several factors including localization, surrounding structures, the rate of growth, tumor volume resection and histological necrosis should be considered in determining prognosis and further adjuvant treatment planning.

Melanotic schwannoma: an 11-year case series

Melanotic or melanocytic schwannoma is a rare tumour usually involving spinal nerve roots but can also present at other anatomical locations. Although there are less than 200 cases reported, melanotic schwannomas can have distinctive imaging features but there is limited recent literature on its often characteristic radiological appearances. Recent publication of the largest case series thus far has suggested melanotic schwannoma to be a separate entity to other schwannomata and that its reclassification to a malignant lesion be under consideration. We present a case series over an 11-year period to highlight salient imaging features with reference to the current concerns regarding its malignant potential.

Spotty skin pigmentation and multiple blue naevi as cutaneous markers for spinal melanotic schwannoma

Spinal melanotic schwannomas are rare spinal tumours with a very poor prognosis in terms of mortality due to difficulty in complete resection and local recurrences. A 67-year-old man presented with acute onset progressive paraparesis for 2 weeks. The patient also had spotty skin pigmentations (blue naevi) in his right lateral thigh. MRI revealed an intradural extramedullary enhancing lesion in the lower thoracic cord level. With a preoperative diagnosis of simple nerve sheath tumour excision was planned. At laminotomy, an infiltrating "en plaque" like lesion reaching up to mid and upper thoracic cord level was identified and excision was carried out. Postoperative histopathology was unique with the identification of melanin and presence of epitheloid cells, with the additional detection of psammoma bodies and adipose-like cells. Melanotic schwannomas though rare and carry poor prognosis must be borne in mind in patients with spotty skin pigmentation and acute onset limb weakness.

Primary thoracic epidural melanoma : a case report

A 68-year-old woman with progressive paraparesis and altered sensation lasting approximately five days was admitted to our clinic. Magnetic resonance imaging (MRI) revealed an advanced stage T7-8 epidural mass ventral to the spinal cord, which was believed to be a metastatic tumor considering the patient's age. A highly enhanced epidural mass and pedicle appeared during the MR scan. However, the pathologic findings were compatible with the diagnosis of a primary meningeal melanocytic tumor. Primary epidural melanomas are extremely rare lesions. This case was finally diagnosed as a primary thoracic spinal epidural melanoma.

Melanotic schwannoma: a case with strong CD34 expression, with histogenetic implications

Melanotic schwannomas (MS) are rare tumors composed of cells with both schwannian and melanocytic features, which usually occur in the setting of Carney's Complex. We describe a case of a 36-year-old male who presented with a mass that was attached to the vertebral body as well as the nerve roots of L2 and L3. Immunohistochemical positivity for S-100, HMB-45, and Pan-melanoma markers, as well as characteristic morphologic and ultrastructural findings, suggested that the lesion was a MS. The interest in this case lies in the fact that this case of MS showed strong CD34 expression, a marker that is generally negative in melanocytic tumors. We discuss the biologic significance of the high CD34 expression by the tumor cells and attempt to shed light on the histogenesis of this rare entity.

MRI features of a primary thoracic epidural melanoma: a case report

We present the magnetic resonance imaging (MRI) findings on a patient with a primary thoracic extradural spinal malignant melanoma. MRI showed a well-defined T1-hyperintense mass that was mostly of low signal on T2-weighted images. Surgery confirmed the presence of a well-encapsulated black-colored lesion which proved to be a melanoma. Extensive searches revealed no other foci of melanoma and no other lesions have appeared during a 6-month follow-up; thus, the diagnosis of primary melanoma was established. Extradural primary melanomas are exceedingly rare. We discuss their differential diagnosis and their probable etiology.

Psammomatous melanotic schwannoma presenting as colonic polyps

Psammomatous melanotic schwannoma is an uncommon neoplasm that usually occurs in the setting of Carney's complex. They can occur in the gastrointestinal tract with preferential location in the stomach. A 43-year-old female presented with two colonic polyps at routine endoscopy. The patient was asymptomatic and did not have features of Carney's complex. Both polyps were composed of melanin-containing epithelioid and spindle cells with several psammoma bodies. There was no evidence of cytological atypia or necrosis. The tumor was diffusely positive for S-100, and focally for HMB-45 and melan-A. The differential diagnosis includes melanoma, GIST, pigmented neuroendocrine tumor, and epithelioid leiomyoma. The lack of malignant features separates this lesion from melanoma while the immunophenotype of the other lesions is characteristic.

Dumbbell-shaped C-2 psammomatous melanotic malignant schwannoma. Case report and review of the literature

The authors present the case of a dumbbell-shaped malignant psammomatous melanotic schwannoma of the upper cervical spine involving the C-2 sensory root. The family of the patient had a history of other malignant stromal tumors, without the Carney complex genetic pattern. The 30-year-old female patient complained of experiencing cervical pain and cervical muscle contractions for 6 months, and was admitted to the hospital. The cervical T1-weighted magnetic resonance (MR) images revealed the presence of a slightly hyperintense C2-3 intra-extradural lesion, moderately enhancing, which had eroded and enlarged the intervertebral foramen. The patient workup also included computed tomography scans and angiography. A posterior approach was used to perform a C2-3 hemilaminectomy, including opening of the dura mater and gross-total removal of the lesion. Histopathological examination of the lesion revealed it to be a malignant psammomatous melanotic schwannoma. The cerebrospinal MR image of the patient obtained at the 12-month follow-up examination demonstrated the presence of tumor progression into the subarachnoid space at the C-3 level. The strong malignancy potential of the lesion must be considered in the future management of the patient, especially due to the presence in the family of other stromal tumors such as gastrointestinal-stromal tumors and malignant melanomas. The authors review all the literature concerning melanotic schwannomas and report 105 cases of melanotic schwannoma that were not related to the Carney complex. The particular focus of their review is on the characteristics of the malignant progression of melanotic schwannoma, such as local recurrences, metastasis, and survival rate.

[Melanotic schwannoma of the temporozygomatic region]

INTRODUCTION

Melanotic schwannoma is a rare benign tumor, which arises from nerve sheath cells. Melanotic differentiation is its most histologic characteristic.

CASE REPORT

We report a case of melanotic schwannoma arising in the temporozygomatic region for a man of 38-year-old. Outcome was favourable after tumor resection.

DISCUSSION

This benign neoplasm occurs pronominally in spinal nerve roots. Craniofacial locations are rare. Most melanotic schwannomas are slow growing tumors, but prognosis can be poor because of local recurrence or malign behavior, especially when multiple lesions are present and/or involve the Carney complex.

Melanotic nonpsammomatous trigeminal schwannoma as the first manifestation of Carney complex: case report

OBJECTIVE

Melanotic schwannoma is a rare neoplasm, classifiable as a peripheral nerve sheath tumor, and differentiated from a typical schwannoma by heavy pigmentation. Psammoma bodies can be visualized in more than 50% of melanotic schwannomas. Half of patients with such "psammomatous melanotic schwannomas" have Carney complex, a dominantly transmitted autosomal disorder. Most recently, the tumor suppressor gene, PRKAR1A, coding for the Type 1alpha regulatory subunit of protein kinase A was found to be mutated in approximately half of the known Carney complex families. Although cranial schwannomas have been described in patients with Carney complex, their numbers are too small to be considered a definite part of the syndrome. Furthermore, only melanotic schwannomas with psammoma bodies are included as diagnostic criteria for Carney complex. The objective of this report is to communicate a case of trigeminal nonpsammomatous melanotic schwannoma as the first manifestation of Carney complex.

CLINICAL PRESENTATION

A 34-year-old woman presented with odontalgia, right V3 hypoesthesia, V2 paresthesia, and diplopia. Magnetic resonance imaging scans of the brain revealed a small tumor with homogenous contrast in the right trigeminal pathway.

INTERVENTION

We performed an extradural approach to the right cavernous sinus by a middle fossa approach. The lateral wall was opened between the cranial nerves, and a soft and black tumor was resected in a piecemeal fashion. Histology and immunohistochemical analysis of the tumor were compatible with melanotic schwannoma, but no psammomatous bodies were identified. Endocrine evaluation showed that this patient's symptoms fulfilled the diagnostic criteria of Carney complex, with lentiginosis, multiple breast ductal adenomas, multiple hypoechoic nodules on thyroid ultrasonography, and a 4 x 5-cm asymptomatic atrial cardiac myxoma, which was removed 15 days after the neurosurgery. Three months later, a recurrence of melanotic schwannoma was identified. Molecular analyses of genomic and somatic deoxyribonucleic acid from the patient found a 578 to 579delTG mutation of PRKAR1A.

CONCLUSION

We present the unusual case of a nonpsammomatous trigeminal melanotic schwannoma associated with Carney complex, with confirmed PRKAR1A gene mutation. Our case highlights that neurosurgeons, in the presence of a melanotic schwannoma, should be aware of the features of the Carney complex because, in such cases, pre- and postoperative management is significantly affected. We also postulate that the absence of psammoma bodies or cranial localization do not exclude this diagnosis.

Aggressive Intramedullary Melanotic Schwannoma: Case Report

OBJECTIVE AND IMPORTANCE:

Intramedullary melanotic schwannomas are very rare lesions; only four cases have been reported previously. We describe a patient with an intramedullary melanotic schwannoma that had a more aggressive course than those reported in the literature, and we review the theories regarding the cause of these lesions.

CLINICAL PRESENTATION:

A 35-year-old man presented with neck stiffness and paraesthesia extending down his right arm upon neck extension. A magnetic resonance imaging scan revealed an intramedullary lesion extending from C4 to C5.

INTERVENTION:

Gross total resection of the mass was performed, and pathological characteristics were consistent with a melanotic schwannoma. Two years after resection the tumor recurred, and the patient was treated with radiation therapy. The tumor progressed 2 years after radiotherapy, and at repeat resection, multiple pigmented foci were present on the surface of the spinal cord and dura consistent with metastatic seeding.

CONCLUSION:

In a patient with intramedullary melanotic schwannoma with an unusually aggressive course, careful follow-up may be essential.