Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.10.3.1 (tyrosinase)
 9,065 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spindle cell melanoma is a rare and distinctive variant of malignant melanoma that is composed of spindled neoplastic cells and includes desmoplastic and neurotropic melanoma. The lack of expression of several melanoma markers may result in a delayed or wrong diagnosis. In this study, we have analyzed in detail the phenotype of the tumor cells in 9 spindle cell melanomas on both paraffin-embedded and frozen material, using melanocytic, neural, and mesenchymal markers. The neoplastic cells expressed the melanocytic markers S-100, Mel-CAM, and NKIC3, but lacked gp100 and Melan-A; tyrosinase and c-Kit were expressed in 2 of 7 cases. Most cases expressed the neural markers p75-nerve growth factor receptor, neural cell adhesion molecule, and NSE. All cases expressed vimentin but lacked the mesenchymal markers CD34 and alpha-smooth muscle actin. Remarkably, all spindle cell melanomas strongly and diffusely expressed the fibroblastic markers Thy1 (CD90) and aminopeptidase N (CD13) and variably expressed the enzyme prolyl-4-hydroxylase, involved in procollagen formation. The coexpression of melanocytic, neural, and fibroblastic markers suggests bidirectional differentiation of neoplastic melanocytes toward (myo)fibroblasts and Schwann cells, a feature that was confirmed by electron microscopy. Furthermore, the lack of CD90 and CD13 staining in a wide range of melanocytic lesions suggests specificity of these markers for spindle cell melanoma.
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PMID:New phenotypical and ultrastructural findings in spindle cell (desmoplastic/neurotropic) melanoma. 1466 57

Melanoma with prominent pigment synthesis or animal-type melanoma (ATM) is a very rare type of melanoma. Its histogenesis has not been elucidated and ultrastructural features have not been described in human beings. We present an additional case of ATM in a 28-year-old woman with positive sentinel node biopsy and provide the results of electron microscopic studies. Histopathologically, the skin lesion was composed of heavily pigmented neoplastic cells mostly arranged as large sheets, focally also in a nodular growth pattern. After bleaching, the neoplastic cells demonstrated round nuclei with 1 or rarely 2 conspicuous nucleoli and a prominent nuclear membrane and abundant, gray, slate-like cytoplasm. Some cells demonstrated round cytoplasmic inclusions. There was no nuclear pleomorphism, and only a few mitotic figures could be found after extensive search. Multiple areas of necrosis en masse of tumor cells were seen. The lymph node biopsy revealed a complete effacement of the lymph node architecture by the extensive proliferation of hyperpigmented cells in the parenchyma. Immunohistochemically, the same pattern of staining was seen on the bleached and unbleached slides both in the skin and in the lymph node. The neoplastic cells stained positively with MiTF (nuclei), NSE, NKI/C3, tyrosinase (weak), p53, and CD68. S-100 protein, HMB45, Melan A, Mac367, and lysozyme reacted negatively. Occasional cells (<1%) reacted with MIB-1. Ultra-structural studies revealed that the neoplastic cells possessed a large, indented nucleus with a prominent nuclear membrane, a single (para) centrally located nucleolus, and peripherally marginated chromatin. The cytoplasm was abundant and contained numerous single melanosomes and rare compound melanosomes. The melanosomes were in stages II to IV of maturation, with a marked predominance of stage II and stage III melanosomes. There was a high number of aberrant melanosomes with a wide variety of configurations. Melanophages were a minor component of the lesion. Our ultrastructural studies provide unequivocal evidence that ATM is a neoplasm of melanosome-producing cells. We also review the literature on ATM.
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PMID:Melanoma with prominent pigment synthesis (animal-type melanoma): a case report with ultrastructural studies. 1524 59

Clear cell sarcoma (CCS) is a high grade soft tissue sarcoma with a distinct molecular profile and with morphological features resembling those of melanoma. CCS has been rarely described in other locations other than the soft tissues, including the gastrointestinal tract. In this study, we report a case of CCS arising in the ileum of a 31-year-old woman. Histologically, the tumor involved the entire thickness of the intestinal wall. Tumor cells were polygonal or fusiform, with clear or eosinophilic cytoplasm, arranged in a uniform nested to fascicular growth pattern. Immunohistochemical studies revealed strong positivity for vimentin and S-100 protein. HMB-45, Melan-A, tyrosinase, cytokeratins, EMA, smooth muscle actin, CD34, CD31, CD117, CD99, synaptophysin, chromogranin A, CD56, and NSE were negative. Fluorescence in situ hybridization analysis demonstrated the presence of a t(12;22)(q13;q12) translocation, the diagnostic hallmark of CCS of soft parts. The present case, together with a detailed review of the literature on this topic, demonstrates that the gastrointestinal tract is a possible site of CCS of soft tissues and that making a reliable diagnosis of this tumor requires cytogenetic or molecular diagnostic investigations.
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PMID:Clear cell sarcoma of the ileum: report of a case and review of literature. 1763 26