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At least 217 records · Page 12Linked to original sources
PubMed2000

Benign melanocytic tumor in infancy: discussion on a rare case and review of the literature.

Meningeal melanocytoma is an infrequent neoplasm of the central nervous system (CNS), especially in childhood and infancy. It was first described as an entity different from pigmented meningiomas and schwannomas in 1972, and few cases have been published so far. In this article, a 5-month-old male patient with meningeal melanocytoma is presented. This midline lesion was localized in the posterior fossa and manifested by hydrocephalus. The entire dural origin and extradural growing pattern in addition to the destruction of the adjacent occipital bone were the unexpected presentations since these tumors usually tend to locate on leptomeninges and to extend into the adjacent neural compartment rather than the outside. On the other hand, this case is the only one which had identical lesions in both surrenal glands and the left renal capsule, the structures containing neural-crest-derived cells outside the CNS. The prognostic criteria, differential diagnosis and its embryological aspects are discussed with an extensive review of the related existing literature.

Animals↗
PubMedDate not supplied

Pigmented neuroectodermal tumor of infancy in the epididymis. A case report.

BACKGROUND: Pigmented neuroectodermal tumor of infancy (PNTI) is a rare pigmentary tumor. Cytologic study of this tumor had not been performed before. In the present study, cytology of such a tumor was done in addition to histology, electron microscopy and immunohistochemistry. CASE: A 5-month-old infant had a scrotal tumor. After tumorectomy, touch smear for cytology revealed small and large tumor cells. The small cells showed a high nuclear/cytoplasmic ratio, and the large cells contained pigment in their cytoplasm. Histologically, the small cells and large, pigmented cells showed a typical alveolar and tubular pattern, respectively. The small cells neuroblastlike and the large cells showed melanocytelike features ultrastructurally and immunohistochemically. CONCLUSION: Cytology has not been applied to the diagnoses of PNTI. In our opinion, fine needle aspiration cytology could be helpful in the preoperative diagnosis of this tumor.

Biomarkers↗
PubMed1994

Neurocutaneous melanosis presenting as an intradural mass of the cervical canal: magnetic resonance features and the presence of melanin as a clue to diagnosis: case report.

We present a case of neurocutaneous melanosis in a 1-year-old child who presented with progressive quadriparesis created by an infiltrating extra-axial neoplastic melanin-producing tumor at the foramen magnum. This extensive intra-arachnoid mass filled the basal cisterns of the brain and surrounded the upper cervical cord. An imaging clue to the diagnosis was apparent as T1-weighted shortening on magnetic resonance in the pia and/or cortex of the cerebellar folia, suggesting the presence of melanin.

Cervical Vertebrae↗
PubMed2006

Review of pineal anlage tumor with divergent histology.

Pineal anlage tumor is an extremely rare tumor that is not listed in the 2000 World Health Organization Classification of nervous system tumors. It has been defined as a primary pineal tumor with both neuroepithelial and ectomesenchymal differentiation and without endodermal differentiation. We review the literature on this tumor, including the clinical presentation, gross pathology, histopathology, immunohistochemistry, differential diagnosis, and prognosis.

Biomarkers, Tumor↗
PubMed2002

[Epididymal tumor in a six-months-old infant].

A rare tumor of the epididymis was discovered in a 6-month-old infant. Macroscopically, the tumor had a black focal color. Immunohistochemistry staining and electron microscopy led to the diagnosis of mealnotic neuroectodermal tumor, or progonoma. Prognosis of progonoma, a benign tumor, is generally good, but malignant transformation has been reported.

Epididymis↗
PubMed1995

MR of parenchymal neurocutaneous melanosis.

Two cases of neurocutaneous melanosis are presented. MR showed hyperintense areas in the brain on short-repetition-time/short-echo-time sequences, compatible with intraparenchymal melanin deposits. No leptomeningeal abnormality was seen.

Brain Neoplasms↗
PubMed1993

Stereolithographic modelling for reconstructive head surgery.

Until now, bounds of model creation of medical objects had to be set because of the limited capabilities of available manufacturing equipment. Recently, stereolithography was developed as an alternative to current milling operations. In this process the surface of a photohardening liquid plastic compound is traced by a laser beam and hardened in layers. The models thus produced are extremely accurate and retain excellent detail. Specific implants can be designed and prepared as is illustrated in a case report. If tissue-compatible plastics are used, custom-made implants could soon be manufactured directly with the technique described.

Child↗
PubMed1996

Regulation by retinoic acid of insulin-degrading enzyme and of a related endoprotease in human neuroblastoma cell lines.

Physiologically, the action of insulin-like growth factors (IGFs) is controlled at different levels, from its transcription start by tissue-specific and development-specific transcriptional factors to its degradation by peptidases such as insulin-degrading enzyme (IDE). Since IGF-II is the major autocrine/paracrine growth factor for neuroblastoma cells, we studied the expression and the role of IDE in this system. Here, we show that (a) IDE is expressed in several human neuroectodermal tumor cell lines, including neuroblastoma cell lines; (b) in a neuroblastoma cell line, IDE expression is up-regulated by retinoic acid, a well-known inducer of neuronal differentiation and/or programmed cell death; (c) IDE is probably not the only IGF-degrading enzyme present in these cells, since the activity of a novel thermolysin-like metalloendopeptidase, clearly distinct from IDE, is also detected. The TME activity is inhibited by IGF-I, Des-IGF-I, and IGF-II, and it is down-regulated by retinoic acid. Since retinoic acid plays a relevant role in controlling the growth of these cells and affects the expression of IDE, we have also: (a) identified the retinoic acid receptors (RARs) and retinoid X receptors (RXRs) expressed in these cell lines and (b) by means of synthetic retinoid analogues identified the RAR/RXR isoforms whose activation may be sufficient to induce the expression of the IDE gene. These results provide evidence that complex posttranslational molecular mechanisms participate in the autocrine/paracrine growth control of the IGF-II loop in neuroblastomas involving proteolytic systems.

Endopeptidases↗
PubMed1978

Melanotic medulloblastoma. Report of a case with ultrastructural findings.

A pigmented neoplasm of the cerebellar vermis in a four year old child was typical of differentiating medulloblastoma with islands of epithelial-like cells containing melanin pigment. There have been several previous reports of such melanotic cerebellar neoplasms. Reported cases have had a clinically malignant behavior with dissemination in the central nervous system. They appear to be variants of medulloblastoma and not pigmented neuroectodermal tumors of infancy (melanotic prognomas or retinal anlage tumors). Ultrastructurally the neoplasm was compatible with medulloblastoma with focal poorly differentiated cells which contained melanin pigment. The pigment resembled neural crest (cutaneous or ocular) melanin rather than neuromelanin.

Cerebellar Neoplasms↗
PubMed2008

Cerebellar medullomyoblastoma with melanotic tubular structures.

This report describes a midline cerebellar primitive neuroectodermal tumor with muscular differentiation, that is, medullomyoblastoma with melanotic tubular structures, which developed in the cerebellar vermis in a 23-month-old male. Rhabdomyoblastic differentiation consisted both of striated muscle fibers and undifferentiated cells showing immunoreactivity for desmin and myogenic transcription factors. The presence of melanotic epithelial structures raised the issue of a teratomatous tumor. This case demonstrates the occurrence of this very rare tumor in early childhood as well as the utility of a careful search for the presence of myogenic and/or melanotic features in medulloblastomas.

Cerebellar Neoplasms↗
PubMedDate not supplied

Melanocytoma of the foramen magnum.

This report concerns a 66-year-old man with a melanocytoma arising at the foramen magnum. Magnetic resonance imaging disclosed a well-circumscribed tumor extending from the medulla oblongata to C1 with gadolinium enhancement. A heavily pigmented tumor located under the leptomeninges was removed surgically. Although the patient died 8 months later of renal cell carcinoma, no recurrence or metastasis of the melanocytoma was detected by radiographic examination. Microscopically, the resected tumor was composed of polygonal to spindle-shaped cells containing large amounts of melanin. The bland nuclei of the tumor cells were of uniform size. No mitotic figures were seen. The tumor cells were positively immunostained for S-100 protein and by antibody HMB-45. They were not stained using the Ki-67 (MIB-1) antibody, indicating low proliferative activity. The ultrastructural examination revealed numerous mature melanosomes and basal laminae surrounding nests of cells. The tumor was diagnosed as a melanocytoma on the bases of its microscopic features and the lack of Ki-67 immunoreactivity. The ultrastructural and immunohistochemical features of melanocytomas are distinct from those of meningiomas. It is likely that melanocytomas and melanotic schwannomas represent opposite extremes of the continuous spectrum of neuroectodermal tumors derived from the neural crest.

Aged↗
PubMedDate not supplied

[Congenital melanotic tumors].

Congenital melanotic tumors are among the very rare tumors of early childhood. Their histogenesis and biological significance are still controversial today. The ideas of an odontogenic origin and of a neuroectodermal pathogenesis of these tumors range among the most frequently advocated hypotheses. Until about 1970 this type of tumor was almost always referred to as benign. Meanwhile there has been a change in the assessment of the character of congenital melanotic tumors. Above all, this is due to the fact that malignant cases have been repeatedly reported since 1970. Apart from an extensive review of the literature, 2 own cases are described which were treated surgically. The histological evaluation of the tumor material supports the assumption that these tumors are of odontogenic origin.

Female↗