Gene/Protein Disease Symptom Drug Enzyme Compound
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 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Congenital giant nevi are complex cutaneous malformations composed of melanocytic and occasionally neural supportive elements. Malignant neoplasms arising in this setting are not uncommon, and their histologic appearances often differ significantly from the typical pattern of malignant melanoma. We report six patients with neoplasms arising in congenital giant nevi and one patient with a neoplasm arising in an extensive congenital blue nevus, and present a description of the neoplastic patterns encountered. These patterns include 1) poorly differentiated small round cell cancer, 2) malignant cellular blue nevus, 3) spindle-cell malignant tumor with lamellar cell (pseudomeissnerian) differentiation, 4) so-called minimal deviation melanoma, 5) heterologous malignant mesenchymal differentiation including rhabdomyosarcoma and liposarcoma, and 6) undifferentiated spindle cell cancer. We have reviewed the literature in order to address the question of frequency of malignant transformation in congenital giant nevi, the reported experience with the morphology of these cancers, and the histogenesis of these sometimes complex neoplasms as it is illuminated by our current understanding of the embryology of the neural crest.
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PMID:Neoplasms arising in congenital giant nevi: morphologic study of seven cases and a review of the literature. 626 95

The occasional occurrence of primary extra-cutaneous malignant melanomas (MM) has led to the hypothesis that melanocytes derived from the neural crest may be arrested in their migration and may undergo an in situ malignant transformation. However, aggregates of nevus cells have only rarely been identified by histological examination in a few organs other than skin and eye. Tyrosinase is a melanin biosynthetic enzyme that is considered one of the most specific markers of melanocytic differentiation. We have attempted to detect cells committed to the melanocytic lineage, in human tissues, by means of tyrosinase gene expression. Total RNA was extracted from normal and neoplastic tissues and analyzed using a highly sensitive reverse transcription PCR assay with primers specific for the tyrosinase gene. Peripheral blood mononuclear cells (PBMC) from healthy subjects were used as negative controls. Tyrosinase transcripts were identified in a wide range of normal organs such as skin, lymph nodes, antrum, colon, kidney, lung, testis, ovary, breast, and peripheral nerve. Tyrosinase RNA was also detected in neoplastic samples including benign cutaneous nevi, lymph nodes involved by MM, breast carcinoma, liposarcoma, malignant lymphoma, and schwannoma. PBMC from patients with metastatic MM were also positive, while no positivity was detected in blood specimens from patients with other cancers. Therefore, it appears likely that cells expressing the tyrosinase gene are present in a wide range of human tissues. Although these cells still have to be accurately identified, one could propose that they might correspond to either fully differentiated melanocytes, melanocytic precursors, or Schwann cells bearing potentialities of melanocytic differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Tyrosinase gene expression in human tissues. 751 6

A variety of malignancies have been reported to arise within congenital melanocytic nevi, most commonly malignant melanoma, but rarely rhabdomyosarcoma, liposarcoma, and malignant peripheral nerve sheath tumor as well. There have been only three documented cases of rhabdomyosarcoma arising within congenital melanocytic nevi: two embryonal rhabdomyosarcomas and one mixed liposarcoma and rhabdomyosarcoma. One of these cases was also associated with neurocutaneous melanosis. We report a fourth case of rhabdomyosarcoma originating from a congenital melanocytic nevus. A 4-year-old girl presented with a large ulcerated nodule that developed within a hairy congenital nevus on her left gluteal and sacral regions. Her parents refused postoperative adjuvant therapy, and she died 13 months after surgical excision. Histologic sections showed a lesion with two distinct components. There was an expansile proliferation of pleomorphic cells within a fibromyxoid stroma. The neoplastic cells were spindled, and some had abundant eosinophilic globular cytoplasm with occasional cross-striations characteristic of rhabdomyoblasts. They strongly expressed desmin and myoglobin and were negative for S-100 protein and HMB-45. The tumor merged with an adjacent congenital melanocytic nevus characterized by a proliferation of uniform nonatypical melanocytes. The finding of both rhabdomyoblastic and melanocytic differentiation within the same lesion lends support to the hypothesis of their derivation from common pluripotential stem cells or neural crest cells.
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PMID:Rhabdomyosarcoma arising in a congenital melanocytic nevus. 1180 77

Congenital melanocytic naevi, consisting of clusters of naevo-melanocytes, develop in utero. Although many congenital naevi are visible at birth, some may not become evident until later in life. The timing of naevo-melanocyte proliferation, senescence and melanogenesis may all contribute towards determining when a naevus will become clinically manifest on the skin. Besides the fact that congenital melanocytic naevi may be aesthetically displeasing, resulting in a multitude of psychosocial issues, they also increase the risk for developing cutaneous melanoma, leptomeningeal melanoma, neurocutaneous melanocytosis, malformations of the brain and, rarely, other tumours such as rhabdomyosarcoma and liposarcoma. Whereas the risk of developing malignancy in association with congenital naevi is dependent, to some extent, on the size of the naevus, the risk of developing neurocutaneous melanocytosis correlates best with the number of satellite naevi. Management of patients with congenital melanocytic naevi requires individualization, taking into account the naevus size and location, and the risk of developing cutaneous melanoma or neurocutaneous melanocytosis. When contemplating treatment options, it is important to set realistic expectations and to address the possible aesthetic and functional outcomes, while at the same time addressing the risk for developing cutaneous and/or extracutaneous melanoma.
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PMID:Congenital melanocytic naevi. 1991 64

Malignant melanoma is commonly known as the great mimicker and can present in various clinical manifestations and with diverse morphological variants. One of the rare histological variants is the signet-ring cell type. The signet-ring morphology has been reported in numerous other neoplasms including adenocarcinoma, lymphoma, liposarcoma, squamous cell carcinoma, and basal cell carcinoma. We report a rare case of primary signet-ring cell malignant melanoma in a 62-year-old man. He initially presented with an enlarging nevus on his right flank with surrounding erythema. A biopsy showed atypical epithelioid and signet cells with prominent nucleoli and occasional mitoses. Initial diagnosis favored metastatic signet-cell carcinoma of gastrointestinal origin. Review of the biopsy and immunohistochemical analysis revealed the malignant signet-ring cells stained with S100, vimentin, and melanoma cocktail, in keeping with melanoma. The signet-cell morphology can be found in a variety of other malignancies. To prevent potential misdiagnoses, thorough histological examination should be aided by an appropriate immunohistochemical panel to confirm melanoma and exclude erroneous differentials.
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PMID:Signet-ring cell melanoma: a potential diagnostic pitfall. 2532 Oct 87

The p16 gene belongs to INK4 family of genes and is made up of four members: p16 INK4A , p15 INK4B , p18 INK4C and p19 INK4D , all of which share biological properties, namely, inhibition of cell growth and tumour suppression. After p53, p16 is the second most common tumour suppressor gene. It has been regarded as the familial melanoma gene. Immunohistochemistry for p16 has a well-defined role in distinct pathological scenarios. It is used to distinguish desmoplastic melanoma from reactive fibrous proliferation, with former showing strong nuclear positivity. In other types of melanoma, p16 protein expression is lost. Spitz nevi show retention of nuclear staining for p16. Benign mesothelial proliferations tend to retain nuclear p16 immunoreactivity, while malignant mesotheliomas lose expression. However, p16 fluorescent in-situ hybridisation analysis is recommended in the workup of malignant mesothelioma. Another common application of p16 immunohistochemistry is as an indicator for human papillomavirus (HPV) infection and p16 protein is overexpressed in HPV-associated tumours. In this context, p16 immunopositivity should be strong, diffuse, nuclear or nuclear and cytoplasmic in location. Another use for p16 is demonstration of p16 immunopositivity in well-differentiated and dedifferentiated liposarcoma.
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PMID:p16. 3007 91

Congenital nevi and fibrolipomatous hamartoma are benign tumors of childhood, the latter being very uncommon. Fibrous hamartoma of infancy typically occurs in <2 years of life. The concurrence of these two lesions is extremely rare. We report a case of congenital fibrolipomatous hamartoma and congenital nevus of infancy in a 6-month-old male infant. Clinically, a suspicion of benign versus malignant lesion beneath the giant congenital nevus prompted its surgical removal. The histopathology confirmed it to be a compound lesion with benign melanocytic nevi and fascicles of spindle cells with eosinophilic cytoplasm representing hamartoma. Several types of melanocytic combined lesions have been noted with neuroectodermal and mesenchymal components. Sometimes, malignant soft-tissue neoplasm such as liposarcoma, rhabdomyosarcoma, and ganglioneuroblastoma do occur. This case report highlights the role of prompt surgical excision and histopathological examination.
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PMID:Concurrent Congenital Fibrolipomatous Hamartoma and Congenital Nevus of Infancy: A Syndromic or Chance Association. 3044 19