Melanotic Schwannoma Research Articles

Melanotic Schwannoma Arising in the Floor of the Mouth

7. Okada K, Frassica FJ, Sim FH, et al: Parosteal osteosarcoma.A clinicopathological study. J Bone Joint Surg Am 76:366,19948. Ritts GD, Pritchard DJ, Unni KK, et al: Periosteal osteosarcoma.Clin Orthop 219:299, 19879. Patterson A, Greer RO Jr, Howard D: Periosteal osteosarcomaof the maxilla: A case report and review of literature. J OralMaxillofac Surg 48:522, 199010. Unni KK, Dahlin BC, Beabout JW, et al: Parosteal osteogenicsarcoma. Cancer 37:2455, 197611. Fechner RE, Mills SE: Tumors of the bones and joints,

Melanotic schwannoma with drop metastases to the caudal spine and high expression of CD117 (c-kit)

Melanotic schwannomas (MS) are tumors of Schwann cell origin characterized by cytoplasmic deposition of melanin. The authors present the case of a 61-year-old man who experienced progressive weakness of the lower extremities over 2 years. This was followed by acute deterioration, which prompted his presentation. MRI of the spine revealed an intradural, extramedullary lesion at the level of T7 with severe spinal cord compression. More caudally, there was involvement of the lumbar spine with drop metastases to the conus medullaris and cauda equina. The patient underwent thoracic laminectomy for tumor resection. A diagnosis of MS was made based on histologic morphology, immunohistochemical profile, and ultrastructural findings. In this report, the authors describe a MS with expression of CD117 (c-kit) and review the literature pertaining to this condition.

Aggressive Intramedullary Melanotic Schwannoma: Case Report

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

APRIL 2004: WOMAN IN HER EARLY FIFTIES WITH A CERVICAL INTRASPINAL AND EXTRASPINAL MASSLESION

April 2004: A 53-year-old woman presented with a large club-shaped intra- and extraspinal tumor of the C6 nerve root which had intradurally grown through the enlarged C5-6 neural foramen and focally infiltrated the dura mater. Microscopy revealed a melanin-pigmented tumor with spindle-shaped and epithelioid cells and scattered psammoma bodies, a so-called psammomatous melanotic schwannoma (PMS). More than half of the patients with PMS have Carney complex, a genetically heterogeneous multiple neoplasia syndrome of autosomal-dominant inheritance, which in our patient, however, could not be detected unequivocally. Prognosis of all melanotic schwannomas (MSs) is not good with local recurrences or metastases in over 40% of cases. In our case, frequent versicular nuclei with distinct nucleoli, occasional mitoses and apoptoses and increased focal MIB-1 labeling indices prompted us to diagnose a malignant PMS. However, histologic criteria for malignancy in MSs are not clearly defined and there is no reliable histopathological indicator of malignant clinical behavior in MSs. Therefore, designation of "PMS with malignant histologic features" may be more appropriate. Since tumor recurrences and metastases im MSs may occur after more than 5 years, long-term follow-up of affected patients is required. One year after operation our patient showed no signs of tumor recurrence or metastases.

A syndrome lost in specialisation

A 46-year-old man with multiple cutaneous lentigines (figure A, B) presented with a 5-year history of back pain, lumbar claudication, and urinary urgency. A tumour, a rare melanotic Schwannoma (figure C), compressing the right L4 nerve root and cauda equina (figure D) was excised. At 18 years of age, he had had a stroke (figure E) secondary to an atrial myxoma embolism. The myxoma and four subsequent recurrences were excised and a pacemaker implanted (figure F). He had also undergone excision of myxomas of his hard palate, ear, parotid gland, and eyelids.

The pathobiologic spectrum of Schwannomas.

In terms of their morphology, clinical associations and behavior, peripheral nerve sheath tumors are among the most varied of human neoplasm. Not surprisingly, such tumors are subject to frequent misdiagnosis. This is particularly true of the spectrum of schwannomas which include: a) conventional schwannoma, a histologically benign tumor which, on occasion, is destructive of surrounding osseous structures, b) the relatively recently described cellular schwannoma, a tumor that histologically simulates malignant peripheral nerve sheath tumor (MPNST), c) plexiform schwannoma which, particularly in cellular form and when occurring in childhood, simulates MPNST, and d) melanotic schwannoma which is often mistaken for melanoma. The psammomatous form of the latter is often associated with Carney complex, a rare heritable disorder that: a) includes cutaneous lentigines, b) myxomas of skin, subcutaneous tissue, and heart, c) and endocrine neoplasms. The tendency to misdiagnose schwannomas and to overestimate their grade makes schwannomas worthy of note. Herein, we discuss the four major schwannoma variants, their essential clinicopathologic features, and differential diagnosis. The distinction from MPNST is given particular attention.

Carney's Syndrome: Complex Myxomas. Report of Four Cases and Review of the Literature

Cardiac myxomas are rare tumors. They usually appear as a sporadic isolated condition in the left atrium of middle-aged women with no other coincidental pathology. Carney and others have described in young people a special complex group of cardiac myxomas associated to a distinctive complex pathology, giving identity to the “Syndrome Myxoma” or “Carney's Syndrome”. Four additional cases of this syndrome, treated from 1977 to 1999 at the Hospital Clínico de la Universidad de Chile are presented here with a comprehensive review of the literature, accumulating 100 cases. The main features of our cases include the presence of malignant non cardiac tumors, a familial trend, follow-up of 23 years and an iterative recurrence in the elder case. To date all patients are tumor free. Reviewing the literature, patients with Carney's Syndrome were younger, with a mean age of 26 years and female predominance (62%). Cardiac myxomas affected the four chambers of the heart: 64% the left atrium; 44% the right atrium; 14% the left ventricle and 12% the right ventricle. They were multiple tumors in 41% and involved more than one chamber in 31%, being synchronous or metachronous. There was a marked familial trend (52%), a high incidence of recurrence (20%), with more than one occurring in half the cases. Extra-cardiac involvement consisted of: 68% pigmented skin lesions, 40% cutaneous myxomas, 37% adrenal cortical disease, 27% myxoid mammary fibroadenoma and 34% male patients with testes tumors. A low percentage had pituitary adenoma, melanotic schwannomas and thyroid disease. The diagnosis is made when two or more of these criteria are present. In agreement with these findings the four chambers of the heart should be examined at surgery for atypical myxoma locations, right atriotomy and combined superior-transseptal approach improve exposure of the cavities, careful screening of the first degree family members should be conducted, and closed short and long term follow up controls are important. Complex myxoma appears as a multi-systemic disorder, occasionally having an ominous prognosis and malignant potentiality, and is still undergoing investigation for better understanding and identification.

Carney’s syndrome: complex myxomas. Report of four cases and review of the literature

Cardiac myxomas are rare tumors. They usually appear as a sporadic isolated condition in the left atrium of middle-aged women with no other coincidental pathology. Carney and others have described in young people a special complex group of cardiac myxomas associated to a distinctive complex pathology, giving identity to the “Syndrome Myxoma” or “Carney’s Syndrome”. Four additional cases of this syndrome, treated from 1977 to 1999 at the Hospital Clínico de la Universidad de Chile are presented here with a comprehensive review of the literature, accumulating 100 cases. The main features of our cases include the presence of malignant non cardiac tumors, a familial trend, follow-up of 23 years and an iterative recurrence in the elder case. To date all patients are tumor free. Reviewing the literature, patients with Carney’s Syndrome were younger, with a mean age of 26 years and female predominance (62%). Cardiac myxomas affected the four chambers of the heart: 64% the left atrium; 44% the right atrium; 14% the left ventricle and 12% the right ventricle. They were multiple tumors in 41% and involved more than one chamber in 31%, being synchronous or metachronous. There was a marked familial trend (52%), a high incidence of recurrence (20%), with more than one occurring in half the cases. Extra-cardiac involvement consisted of: 68% pigmented skin lesions, 40% cutaneous myxomas, 37% adrenal cortical disease, 27% myxoid mammary fibroadenoma and 34% male patients with testes tumors. A low percentage had pituitary adenoma, melanotic schwannomas and thyroid disease. The diagnosis is made when two or more of these criteria are present. In agreement with these findings the four chambers of the heart should be examined at surgery for atypical myxoma locations, right atriotomy and combined superior-transseptal approach improve exposure of the cavities, careful screening of the first degree family members should be conducted, and closed short and long term follow up controls are important. Complex myxoma appears as a multi-systemic disorder, occasionally having an ominous prognosis and malignant potentiality, and is still undergoing investigation for better understanding and identification.

Immunohistochemical staining for KIT (CD117) in soft tissue sarcomas is very limited in distribution.

We performed immunohistochemical analysis for KIT in 365 soft tissue sarcomas. Most tumors evaluated were completely negative for KIT, including all cases of leiomyosarcoma, rhabdomyosarcoma, myxofibrosarcoma, liposarcoma, solitary fibrous tumor, synovial sarcoma, dermatofibrosarcoma protuberans, schwannoma, malignant peripheral nerve sheath tumor, clear cell sarcoma, low-grade endometrial stromal sarcoma, and follicular dendritic cell sarcoma. Tumors showing occasional immunoreactivity for KIT included extraskeletal myxoid chondrosarcoma (2/20), Ewing sarcoma/malignant primitive peripheral neuroectodermal tumor (4/20), melanotic schwannoma (3/5), metastatic melanoma (4/20), and angiosarcoma (5/20). In most cases, staining for KIT was focal. Rare tumor cells showing KIT positivity were identified in a small number of other tumors. This study demonstrates very limited expression of KIT in soft tissue tumors other than gastrointestinal stromal tumors and underscores the discriminatory value of KIT immunohistochemical analysis for differential diagnosis. As some of these findings differ markedly from previous reports, it is evident again that variations in immunohistochemical technique can lead to major discrepancies in positive staining. Since treatment eligibility for selective tyrosine kinase inhibitors such as STI571 hinges on positive immunostaining, standardization and reproducibility of meaningful results are critically important.

Pituitary Adenoma in Carney Complex: An Immunohistochemical, Ultrastructural, and Immunoelectron Microscopic Study

First described in 1985, Carney complex is a rare, heritable disorder featuring abnormal skin pigmentation, cardiac and cutaneous myxoma, melanotic schwannoma of psammomatous type, and endocrine abnormalities, including pituitary adenomas. Patients with the latter present with elevated growth hormone (GH) levels and acromegaly or gigantism. Prolactin (PRL) elevation may also be seen. The authors have investigated 2 resected pituitary adenomas from patients with Carney complex. One, a 19-year-old female acromegalic with elevated GH, IgF-1, and PRL levels, had a mammosomatotroph adenoma immunoreactive for GH and PRL. Ultrastructurally, GH and PRL were present in the same secretory granules. The second patient, a 27-year-old acromegalic, had a sparsely granulated GH cell adenoma that by immuno-electron microscopy revealed GH immunoreactivity only. The lack of morphologic similarity between the 2 adenomas indicates that pituitary tumors in patients with Carney complex may not exhibit the same phenotype.

A Muscle Mass in a Patient with Polymyalgia Rheumatica

We report the extremely uncommon case of a 77-year-old woman in whom a tumor found to be a melanotic schwannoma, arising from the right rectus abdominis muscle, was detected during investigation for a rheumatic disorder, finally identified as polymyalgia rheumatica (PMR). Tumors of this type most commonly occur in spinal nerve roots, and their clinical behavior is very difficult to predict. As far as we are aware, this is the first reported case affecting the aforementioned site. The challenging issue in this case concerns the possible link between the 2 clinical conditions, in particular the development of PMR as a paraneoplastic syndrome. Although such an association has not been reported, PMR is included among the rheumatic disorders reported to be associated with malignancies and occasionally with benign tumors. However, given that tumor resection did not result in remission of PMR and symptoms improved rapidly with prednisone, it seems likely that the above disorders might simply coexist.

Microphthalmia transcription factor and melanoma cell adhesion molecule expression distinguish desmoplastic/spindle cell melanoma from morphologic mimics.

Desmoplastic/spindle cell melanoma is a rare variant of melanoma. A number of factors complicate the diagnosis of desmoplastic/spindle cell melanoma, including the variable absence of a lentiginous component, its spindle cell morphology, and its many morphologic mimics, including scars, malignant peripheral nerve sheath tumor, neurofibroma, atypical fibroxanthoma, and spindled carcinoma. The immunohistochemical confirmation of desmoplastic/spindle cell melanoma may also be difficult, because the majority of tumors are negative for specific melanocytic markers such as HMB-45 and Melan-A, despite their usual expression of S-100 protein. Two new and potentially promising melanocytic markers, microphthalmia transcription factor (MiTF) and melanoma cell adhesion molecule (Mel-CAM), have been shown to be sensitive markers of epithelioid melanoma, but have not been tested in desmoplastic/spindle cell melanoma or in other rare melanocytic neuroectodermal tumors such as clear cell sarcoma. We immunostained 79 tumors (20 desmoplastic/spindle cell melanomas, 10 scars, 10 neurofibromas, 12 malignant peripheral nerve sheath tumors, 10 atypical fibroxanthomas, 10 clear cell sarcomas, 3 melanotic schwannomas, and 4 cellular blue nevi) for MiTF and Mel-CAM. MiTF expression was seen in 11 of 20 desmoplastic/spindle cell melanomas, 0 of 10 scars, 2 of 10 neurofibromas, 0 of 12 malignant peripheral nerve sheath tumors, 1 of 10 atypical fibroxanthomas, 7 of 10 clear cell sarcomas, 3 of 3 melanotic schwannomas, and 3 of 4 cellular blue nevi. Mel-CAM expression was present in 14 of 17 desmoplastic/spindle cell melanomas, 0 of 10 scars, 4 of 10 neurofibromas, 3 of 11 malignant peripheral nerve sheath tumors, 0 of 10 atypical fibroxanthomas, 9 of 10 clear cell sarcomas, 3 of 3 melanotic schwannomas, and 0 of 4 cellular blue nevi. MiTF and Mel-CAM were coexpressed in 6 of 17 desmoplastic/spindle cell melanomas and in no other tumor. Regarding desmoplastic/spindle cell melanoma, scar, neurofibroma, malignant peripheral nerve sheath tumor, and atypical fibroxanthoma, the sensitivity and specificity of MiTF for desmoplastic/spindle cell melanoma were 55% and 91%, respectively. For this same group of tumors, Mel-CAM had a sensitivity of 82% and a specificity of 83%. We conclude that the sensitivity and specificity of MiTF for desmoplastic melanoma equals or exceeds that of such markers as HMB-45 or Melan-A, and that MiTF should be part of the initial immunohistochemical panel for the work-up of such cases. Mel-CAM, while very sensitive, is relatively nonspecific, because it is also expressed in a variety of mesenchymal tumors and carcinomas. Mel-CAM is best reserved for cases morphologically suspected to be desmoplastic/ spindle cell melanoma, in which S-100 is positive and MiTF and other melanocytic markers are negative. These markers may also be helpful in certain other differential diagnoses, such as distinguishing clear cell sarcomas from epithelioid malignant peripheral nerve sheath tumors.

Mutations of the gene encoding the protein kinase A type I-alpha regulatory subunit in patients with the Carney complex.

Carney complex (CNC) is a multiple neoplasia syndrome characterized by spotty skin pigmentation, cardiac and other myxomas, endocrine tumours and psammomatous melanotic schwannomas. CNC is inherited as an autosomal dominant trait and the genes responsible have been mapped to 2p16 and 17q22-24 (refs 6, 7). Because of its similarities to the McCune-Albright syndrome and other features, such as paradoxical responses to endocrine signals, genes implicated in cyclic nucleotide-dependent signalling have been considered candidates for causing CNC (ref. 10). In CNC families mapping to 17q, we detected loss of heterozygosity (LOH) in the vicinity of the gene (PRKAR1A) encoding protein kinase A regulatory subunit 1-alpha (RIalpha), including a polymorphic site within its 5' region. We subsequently identified three unrelated kindreds with an identical mutation in the coding region of PRKAR1A. Analysis of additional cases revealed the same mutation in a sporadic case of CNC, and different mutations in three other families, including one with isolated inherited cardiac myxomas. Analysis of PKA activity in CNC tumours demonstrated a decreased basal activity, but an increase in cAMP-stimulated activity compared with non-CNC tumours. We conclude that germline mutations in PRKAR1A, an apparent tumour-suppressor gene, are responsible for the CNC phenotype in a subset of patients with this disease.

Psammomatous melanotic schwannoma: presentation of a rare primary lung tumor

A 30-year-old nonsmoking man underwent a left lower lobectomy with bronchoplasty for an obstructing lesion of the left lower lobe. Pathology results demonstrated a psammomatous melanotic schwannoma, a rare pigmented neural tumor of which only 25 cases have been reported as originating in the respiratory tract.

Fine‐needle aspiration diagnosis of psammomatous melanotic schwannoma

A 51-yr-old male presented with an 8-mo history of lower back pain. Computerized axial tomography (CT) and magnetic resonance imaging (MRI) studies showed a 3.5 × 3.0 cm sacral mass within the spinal canal in the region of the left S2 nerve root. A fine-needle aspirate biopsy (FNAB) was performed under CT guidance. The cytologic findings included a spindle-cell population with a fibrillary background arranged in a vaguely streaming pattern, wavy nuclei with mild atypia, wispy cytoplasm, rare intranuclear inclusions, and dilated vascular spaces. Some cells contained a nonrefractile granular brown pigment consistent with melanin. Also identified were calcified concentric laminations typical of psammoma bodies. Immunohistochemically, the neoplastic cells were strongly immunoreactive for S-100 protein and HMB-45. A diagnosis of psammomatous melanotic schwannoma was rendered. No stigmata of Carney's complex were identified on physical examination. The patient has declined the recommendation of surgical excision of the mass. We herein describe a case unequivocally diagnosed as psammomatous melanotic schwannoma by FNAB. Diagn. Cytopathol. 23:55–58, 2000. © 2000 Wiley-Liss, Inc.

Melanotic schwannoma mimicking myositis ossificans.

Pelvic radiographs of a 20-year-old woman showed a bony mass lesion lateral to the left iliac bone. CT and Tc-99m MDP whole-body scanning were also performed for further assessment. All studies strongly suggested a diagnosis of myositis ossificans; however, a pathologic diagnosis of melanotic schwannoma was made after the mass was excised. Cases of melanotic schwannoma have been reported in different anatomic locations, some of which were reported to be a component of the Carney complex. Further diagnostic work-up in this patient revealed no other signs of this complex.

Spinal melanotic schwannoma: a tumour with poor prognosis

To clarify the prognosis of melanotic schwannoma. This is a rare tumour which is generally considered as a benign lesion, reported in many cases with a short follow-up only. Five cases of spinal melanotic schwannoma were retrospectively studied. The tumours were examined using standard histological, immunohistochemical and ultrastructural methods. No features of malignancy (high mitotic count, atypia or necrosis) were found in the primary tumours. The follow-up period ranged from 3 to 7 years. Malignant clinical behaviour was clear-cut in four cases: three patients died from metastases to various sites and one presented several discrete spinal tumours of the same type seven years after the first operation. Only one patient presented no recurrence and was free of disease 6 years after initial diagnosis. The review of 57 cases of the literature (including our cases), showed that 15% of the cases had recurrences and 26.3% were complicated by metastasis. Only 53% of the cases followed for more than 5 years, were free of disease vs. 67.5% of the cases with shorter follow-up. Twenty additional cases had no follow-up. Appropriate long-term follow-up is required for all melanotic schwannomas, as it may recur or metastasize after more than 5 years, even in the absence of overt malignant histological features.

Melanotic Schwannoma

A case of a melanotic schwannoma presenting as a soft tissue mass of the abductors of the hip is reported. The radiographic findings suggested myositis ossificans, but several subtle findings raised the concern for something else. A bilobed appearance, lack of classic zoning pattern of the ossification, and atypical pain pattern should alert the physician. Biopsy should be considered if the radiographic and clinical presentations are not classic for myositis ossificans.

Intramedullary melanotic schwannoma. Report of a case and review of the literature

A case of an intramedullary melanotic schwannoma located in the spinal cord at the T2-T3 level is described. The lesion occurred in a 44-year-old woman with a 10-year history of weakness and sensory numbness in both legs and feet. At operation the lesion appeared as a well-demarcated grey-brown intramedullary mass. Histologically, it was composed of interlacing bundles of spindle cells showing their cytoplasm filled with melanin. Among spinal cord neoplasms, melanotic schwannomas are rare tumours, which have apparently been reported only in three previous instances. The clinical, diagnostic and pathological features, as well as the possible aetiology of these rare tumours are discussed.

Ophthalmic Eponyms From the Mayo Clinic

Ophthalmic Eponyms From the Mayo Clinic