Melanotic neuroectodermal tumor of infancy. A review of seven cases

The melanotic neuroectodermal tumor of infancy (MNTI) is a rare, usually benign, pigmented neuroectodermal tumor which most often involves the maxilla. The authors reviewed seven cases of MNTI, with patient ages of our patients ranged from nine weeks to 18 months; six of the seven were less than six months old at initial diagnosis. Four patients were males, and all were white. One tumor each was located in the femur, the temporal bone, and the epididymis; the remaining lesions occurred in the maxilla. Three of the four maxillary tumors recurred locally; the epididymal and femoral tumors metastasized. Two of these cases had unique clinical or pathologic features. The case of the femoral tumor is remarkable in that it is the first reported one of MNTI presenting in a long bone. This tumor was aggressively malignant; within two months after its discovery, a large mass of similar tumor was formed in the pelvis, and the tumor resulted in the patient's death. To the authors' knowledge, the case of the temporal bone tumor is the first one of MNTI in which neuronal differentiation of the neuroblastic cells is convincingly demonstrated. This finding provides additional evidence in support of the neuroectodermal theory of origin of these neoplasms.     

婴儿色素性神经外胚瘤临床病理观察

目的：探讨色素性神经外胚瘤的病理形态、免疫组化及诊断和鉴别要点。对5例色素性神经外胚瘤病例进行临床病理、免疫组化及电镜观察。结果：色素性神经外胚瘤好发于1岁以内的婴儿，3例肿瘤发生在上颌骨，2例发生在附皋。镜下由两种细胞构成，即上皮样瘤细胞和小圆形似成神经细胞样瘤细胞。免疫组化示上皮样瘤细胞CK、HMB45阳性，小圆形瘤细胞NSE阳性，超微结构显示肿瘤细胞内分别可见前黑色素小体、黑色素小体和神经内分泌颗粒。结论：色素性神经外胚瘤是一种少见的原始性神经外胚层肿瘤，生物学行为属于潜在恶性或低度恶性肿瘤。     

Immunocytochemical and ultrastructural studies of the histogenesis of Ewing's sarcoma and putatively related tumors

The histogenesis of Ewing's sarcoma (EW) and extraskeletal Ewing's sarcoma (EEW) is still disputable. Their relationship to the so-called Askin's tumor, neuroectodermal tumor of bone, and peripheral neuroblastoma remains to be established. In an attempt to clarify these points, immunocytochemical and ultrastructural studies were done on tissues from 14 cases of EW, 4 cases of EEW, and 9 cases of primitive neuroectodermal tumor (PNET) and compared with neuroblastoma and olfactory neuroblastoma. Six tumors categorized initially as EW and EEW on biopsy, turned out to be PNET by extensive histologic and/or ultrastructural observations. Abundant glycogen was recognized not only in 16 of 18 cases of EW and EEW, but also in seven of nine cases of PNET. Fine fibrillar cell processes were seen between tumor cells, at least in limited areas even in cases of EW and EEW. Immunocytochemically, neuron-specific enolase (NSE), neuroblastoma cell surface antigen (NBCA), neuron cell surface antigen (NCSA), and neurofilament (NF) were demonstrated not only in neuroblastoma, but also frequently in cases of EW, EEW, and PNET. The results seem to suggest that EW and EEW represent the most immature forms of neuroectodermal tumor. Electron microscopic study showed predominantly primitive cells with occasional areas of cell processes, neurosecretory granules, and microtubules, suggesting a neuroectodermal origin.     

Malignant melanotic neuroectodermal tumor: light and electron microscopic study

An 11-year-old white boy had a melanotic neuroectodermal tumor of infancy (MNTI) in his right mandible. Gross-examination showed that the tumor had originated in the right lower dental nerve, destroyed the right mandible, infiltrated the surrounding soft tissues, and metastasized to several lymph nodes. The typical alveolar pattern was observed in most of the tumor mass; however, solid areas with neuroblastic features were present in the infiltrating and metastasizing portions of the tumor. Ultrastructural study demonstrated unequivocal neuroblastic and melanocytic differentiation.     

外周原始神经外胚层肿瘤形态学免疫表型及临床预后研究

目的：探讨外周原始神经外胚层肿瘤(PNET)的临床表现，病理及免疫组织化学特点及预后。方法：对15例外周原始神经外胚层肿瘤进行临床资料及预后，病理组织形态学和超微结构特点及免疫组化表型研究。结果：患者以男性为主，男女之比约为6．5：1，年龄6～35岁，年龄中位数为16，发生部位较多，可发生在直肠，腹膜后，腹股沟，淋巴结，胸壁，睾丸，鼻腔及骨组织等；免疫组化：肿瘤均弥漫表达CD99，并不同程度地表达NSE，SYN，CgA等，但不表达CK，Desmin，LCA等，其中1例表达组织化学染色PAS，随访最长时间为24月。结论：PNET是一种发生在年轻男性，进展迅速，预后非常差的恶性小圆细胞肿瘤，认识其临床病理特点及免疫组化表型对于该恶性肿瘤的诊断及临床治疗意义重大。     

Primitive pineal tumor with retinoblastomatous and retinal/ciliary epithelial differentiation: an immunohistochemical study

A one year old boy was found to have a large tumor encompassing the pineal region and extending towards the third and lateral ventricles and quadrigeminal plate. The tumor was composed mostly of small, undifferentiated cells. Some small cells were arranged in Flexner-Wintersteiner rosettes and a few displayed fleurettes. The tumor contained immature cartilage and skeletal muscle and numerous clusters of pigmented epithelial-like cells which, histologically, resembled those found in melanotic neuroectodermal tumors of infancy (retinal anlage tumors) and retinal or ciliary epithelium. Immunologic stains demonstrated neurofilaments, synaptophysin and retinal S-antigen in some of the small cells and transthyretin in some of the epithelial-like cells. The findings indicate that certain primary pineal parenchymal tumors have features in common with tumors of the ocular medullary epithelium.     

Prognoma of maxilla

Prognoma is a rare dysembryogenic tumour of infancy Very few cases have been recorded in the world literature so far A case report of this tumour affecting a female child with involvement of the right maxilla is being presented Histopathologically prognoma is a melanotic neuroectodermal tumour An increased level of a-fetoprotem m the serum and vanillylmendilic acid (V M A ) in a 24 hours urine sample have been reported with prognoma.     

Melanotic neuroectodermal tumor of infancy: Report of a case with ganglionic differentiation

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare but well-documented lesion of neuroectodermal derivation. Maturation of the neural elements has been reported only occasionally. We report a case of MNTI of the maxilla showing maturation of neural elements to ganglionic cells. © Wiley-Liss, Inc.     

Disseminated primitive neuroectodermal tumor: diagnosis using immunocytochemistry, electron microscopy, and molecular probes

A patient with a disseminated small cell tumor presented with hyperuricemia, gingival hypertrophy, lymphadenopathy, and bone marrow replacement with tumor cells. Initial histologic examination and clinical presentation were consistent with presumed marker silent lymphoma/leukemia. Despite initial treatment with and response to lymphoma/leukemia therapy the patient relapsed in the testis, bone marrow, pancreas, and skin whereupon subsequent and retrospective immunocytochemical, ultrastructural, cytogenetic, and molecular analysis led to the diagnosis of primitive neuroectodermal tumor (PNET). Despite extensive investigation and autopsy no primary site of tumor could be found demonstrating that PNET should be considered in the differential diagnosis of disseminated small cell tumors without an apparent primary.     

Non Malignant Maxillary Lesions: Our Experience

A wide variety of lesions occur in maxilla. Non specificity of clinical and radiological features makes diagnosis of these lesions a difficult task. We report six interesting cases of maxillary swelling among a total number of 37 such lesions of maxilla. These six cases are as follows two cases of central giant cell granuloma, two cases of fibrous dysplasia, one case of pigmented melanotic neuroectodermal tumor and one case of solitary myofibroma.     

Enhanced tumorigenicity, melanogenesis, and metastases of a human malignant melanoma after subdermal implantation in nude mice

Transplantation of human tumors into the organ or tissue of their origin (orthotopic transplantation) in nude mice can result in significant enhancement of tumor growth and metastases, compared with sc (ectopic) transplantation. Because melanocytes are normally found in the epidermal-dermal junction, intradermal inoculation of melanoma cells might be expected to improve their potential for malignant growth as xenografts. The purpose of our study was to examine this possibility. We found that because mouse epidermis and dermis are so thin, it was not possible to inject a bolus of tumor cells intradermally; instead the cells were actually deposited in the most superficial layer of the subcutis (i.e., subdermally). We evaluated the behavior of cells from a human melanoma cell line after sc or subdermal inoculation into National Institutes of Health Swiss athymic nude mice. The cells used were from (1) the predominantly amelanotic human malignant melanoma cell line MeWo, originally established from a melanotic lymph node metastasis, and (2) two MeWo variants resistant to wheat germ agglutinin (WGAr), which were selected for altered malignant capacities. Whereas 5 X 10(5) MeWo cells were required to achieve 100% tumor take with sc injection, only 2 x 10(4) cells were required with subdermal inoculation. Subdermal injection of the MeWo cells resulted in the development of highly melanotic and nonencapsulated primary tumors, which grew quickly into the dermis and epidermis and metastasized at high frequency to draining lymph nodes. In contrast, the tumors that developed after sc injection were found in the deepest layer of the subcutis and were predominantly amelanotic and encapsulated; they rarely metastasized to lymph nodes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Melanotic primitive neuroectodermal (neuroepithelial) tumor of medulla

A 69-year-old man had a melanotic primitive neuroectodermal tumor of the medulla displaying various neuroepithelial elements including undifferentiated neuroepithelial cells forming Homer Wright's rosettes as well as neoplastic neuroglia resembling those seen in medulloblastoma. The neuroglial tumor cells were verified by demonstrating glial fibrillary acidic protein (GFAP) in the cells. These findings support the concept that the primitive neuroectodermal tumor and medulloblastoma are similar neoplasms. They have been described by such diverse names as melanotic medulloblastomas and progonomas. Review of 18 reported cases of intracranial melanotic primitive neuroectodermal tumors, including the present one, reveals that they have common pathologic features, are most frequent in the cerebellum and fourth ventricle, often metastasize widely within the neuraxis or even systemically, occur more frequently in children than adults, and strike males more often than females.     

Simultaneous occurrence of melanotic neuroectodermal tumor and brain heterotopia in the oropharynx.

A case is described of heterotopic brain tissue with simultaneous occurrence of melanotic neuroectodermal tumor in the oropharynx of a 6-week-old infant. The melanotic neuroectodermal tumor was embedded within the heterotopic glial tissue. This coexistence leads us to speculate that a defect causing a pinching-off of both neural crest cap and medullary epithelium of neural tube might have taken place at, or before, the 25-30 somite stage. The displaced embryonic structures subsequently differentiated into glial tissue, choroid plexus, and melanotic neuroectodermal tumor. This observation may be interpreted as further support in favor of a neural crest origin of juvenile melanotic neuroectodermal tumor.     

Large cell medulloblastoma with myogenic and melanotic differentiation: a case report with molecular analysis

We present a case of large cell medulloblastoma with myogenic and melanotic differentiation arising in the cerebellar vermis of a 2-year-old boy and following an aggressive clinical course. Histologic and immunohistochemical features of this tumor include primitive neuronal, rhabdomyoblastic, and pigmented epithelial elements, along with large cell features. Immunohistochemical and molecular data (c-myc gene amplification and the presence of isochromosome 17q) support the contention that this histologically diverse tumor represents a pattern of medulloblastoma with striated muscle and pigmented epithelial differentiation, rather than a teratoma or a cerebellar variant of melanotic neuroectodermal tumor of infancy (‘progonoma’).     

Primary B-cell malignant lymphoma of the maxilla with a sarcomatous pattern and multilobated nuclei

Three cases of primary malignant lymphoma of the maxilla are reported. The primary intraosseous origin of these tumors was demonstrated by x-ray examination and surgical exploration. The initial interpretation as odontogenic infection led to a delay in starting therapy of 9 months in one case. Biopsies of two cases were initially interpreted as sarcoma because of a dense reactive fibrosis between the tumor cells. Subsequently, hemimaxillectomy was performed in one case. Histologically and ultrastructurally the tumor cells showed marked nuclear abnormalities with cleavage, folding, and lobulation. Immunohistochemical studies of two cases showed a monoclonal immunoglobulin expression, IgG-K; T-lymphocyte-associated antigens were not detected on the tumor cells. The findings indicate the existence of a primary B-cell malignant lymphoma of bone with multilobated nuclei. The lymphoid nature may be masked by a dense proliferation of connective tissue. The relation of these tumors to the classifications for malignant lymphoma of lymph node is discussed.     

Ependymoblastoma associated with prenatal exposure to diphenylhydantoin and methylphenobarbitone

Ependymoblastoma developed in a 28-month-old girl whose epileptic mother took diphenylhydantoin and methylphenobarbitone throughout pregnancy. The child was also shown to be a genetic carrier for ornithine transcarbamylase deficiency, an x-linked inborn error of urea cycle metabolism. The possibility of transplacental carcinogenesis should be considered, as other juvenile embryonic tumors such as neuroblastoma, melanotic neuroectodermal tumor, and mesenchymoma have been reported in offspring after diphenylhydantoin use by the mother during pregnancy.     

Sinonasal primitive neuroectodermal tumor arising in a long-term survivor of heritable unilateral retinoblastoma.

BACKGROUND. Patients who survive retinoblastoma (RB) are at risk for having second nonocular tumors, usually osteosarcomas, which often are fatal. Such patients almost always have bilateral RB. METHODS. This article reports a woman who, at the age of 1 year had been cured of a unilateral RB by radiation therapy and enucleation. Eighteen years later, she had a sinonasal small cell tumor that rapidly recurred and proved fatal 2 months after surgical debulking. The tumor was studied by immunohistochemistry and electron microscopic (EM) examination. RESULTS. It showed diffuse neuron-specific enolase staining, focal weak staining for chromogranin, synaptophysin, and Leu-7 monoclonal antibodies in paraffin-embedded, B5-fixed tissue (Great Lakes Diagnostics, Troy, MI). EM study showed an undifferentiated primitive neuroectodermal tumor with many polyribosomes, simple cell junctions, few microtubules, and rare dense core granules. CONCLUSIONS. The combined immunohistochemical, ultrastructural, and clinical features of the tumor were interpreted as a sinonasal primitive neuroectodermal tumor with early neuronal differentiation. The tumor was pathologically indistinguishable from poorly differentiated olfactory neuroblastoma (ONB) and Ewing sarcoma.     

Intracranial and Spinal Melanotic Schwannoma in the Same Patient

Melanotic schwannoma is a nerve sheath tumor composed of melanin - producing cells with ultrastructural features of Schwann cells, which is very rare. These tumors can appear intracranially and less common in the spinal canal. The prognosis is usually good although cases with metastases and death are described in the literature. We present the unusual and rare case of a young man with a spinal melanotic schwannoma at L5/S1 who presented 30 months later with an intracranial melanotic schwannoma.     

Melanin in a dentigerous cyst and associated adenomatoid odontogenic tumor

The authors report on a case of dentigerous cyst associated with odontogenic adenomatoid tumor in an 8-year-old black Nigerian boy. Both the cyst and the tumor contained melanocytes and melanin-laden epithelial cells. To their knowledge this is the first reported case of melanotic follicular cyst and adenomatoid tumor. A review of the literature revealed that melanin is rarely found in odontogenic lesions. Since the neural crest influence on the development of odontogenic tissues is well established, the occurrence of melanocytes in these tissues is not surprising. A racial predisposition may be present; black patients predominated in the 15 reported cases of melanotic odontogenic lesions.     

Amelanotic malignant melanoma of the esophagus: case report and review of the literature

A case of amelanotic malignant melanoma of the esophagus in a 76-year-old woman is reported. A whitish polypoid tumor, measuring 3 x 2 x 2.7 cm, surrounded by black pigmented mucosa, was detected in the middle intrathoracic esophagus. The tumor showed a lobulated surface lined by squamous cell layer, and had epithelioid and polyhedral cells forming alveolar clusters. Melanin pigments or stainability for the dihydroxyphenylalanine (DOPA) reaction were only observed in a few tumor cells. Junctional changes and mucosal melanosis, however, were found freely in the mucosa around the tumor. Many tumor cells showed a strongly positive immunohistochemical reaction for neuron specific enolase (NSE) and S100 protein. The patient died of widespread metastases six months after surgery. Further, a review of 106 reported cases of primary esophageal malignant melanoma, including 29 autopsies, was made; the melanomas were found to include 10 of amelanotic type, eight of which had been misdiagnosed at biopsy. Junctional changes could be found in the mucosa over or around the tumor, in four cases, and mucosal melanosis in one. Lymph node metastasis was the most frequently observed development at autopsy regardless of whether the tumor was amelanotic or melanotic. For correct diagnoses of melanomas of the amelanotic type, peripheral mucosal findings, such as junctional changes or melanosis, should be helpful; and, in order to obtain a good prognosis, a careful resection of the regional lymph nodes could prove valuable.