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William G Campbell - One of the best experts on this subject based on the ideXlab platform.
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primary treatment of choroidal Amelanotic Melanoma with photodynamic therapy
Clinical and Experimental Ophthalmology, 2005Co-Authors: Mark J Donaldson, Lyndell L Lim, Alex C Harper, John Mackenzie, William G CampbellAbstract:The management of choroidal Melanoma involves a delicate balance between preserving vision and preventing metastasis. Plaque brachytherapy has become standard management of most small lesions; however, this can result in radiation retinopathy and optic neuropathy. Transpupillary thermotherapy avoids these side-effects; however, it can also result in visual loss and its effectiveness is limited in Amelanotic lesions. Photodynamic therapy with verteporfin has shown promise in animal studies of choroidal Melanoma, and has recently been used in the management of lesions that have failed to respond to conventional therapy. The authors report a case of primary treatment of a small choroidal Amelanotic Melanoma with photodynamic therapy using verteporfin.
Daniel M Albert - One of the best experts on this subject based on the ideXlab platform.
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spontaneous uveal Amelanotic Melanoma in transgenic tyr ras ink4a arf mice
Archives of Ophthalmology, 2005Co-Authors: William H Tolleson, Jason C Doss, John R Latendresse, Alan Warbritton, William B Melchior, Lynda Chin, Richard R Dubielzig, Daniel M AlbertAbstract:Objective To characterize a murine model of spontaneous Amelanotic Melanoma arising in the uvea of transgenic mice bearing a targeted deletion of the Ink4a / Arf tumor suppressor locus (exons 2 and 3) and expressing human H- ras controlled by the human tyrosinase promoter. Methods Ocular lesions developed in 20 (15.7%) of 127 male albino Tyr-RAS + Ink4a/Arf −/− transgenic FVB/N mice within 6 months, and were evaluated histologically and ultrastructurally. Results Uveal Melanomas were locally invasive but confined to the eye, with no evidence of metastasis. Tumor cells exhibited epithelioid and spindle-shaped morphological features and closely resembled the human counterpart. Melan-A, S100 and neuron-specific enolase expression were detected immunohistochemically. Melanosomal structures were detected using electron microscopy. The retinal pigment epithelium was intact above small Melanomas, and electron microscopy of the tumors failed to show the presence of basement membrane formation or desmosomes. Conclusion Spontaneous uveal malignant Melanomas occurring in male Tyr-RAS + Ink4a/Arf −/− transgenic mice arise within the choroid or ciliary body and share histopathological features characteristic of human uveal Melanoma. Clinical Relevance Uveal Melanoma research has benefited from xenograft models, but engineered mouse models of spontaneous uveal Amelanotic Melanoma will undoubtedly further our understanding of the genetic underpinning for this disease.
Giovanni Pellacani - One of the best experts on this subject based on the ideXlab platform.
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hyporeflective pagetoid cells a new clue for Amelanotic Melanoma diagnosis by reflectance confocal microscopy
British Journal of Dermatology, 2014Co-Authors: A Losi, Caterina Longo, A M Cesinaro, Elisa Benati, Alexander Michael Witkowski, Pascale Guitera, Giovanni PellacaniAbstract:Summary Background Amelanotic Melanoma represents a diagnostic challenge both clinically and dermoscopically. Few studies based on case series have explored the possibility of using reflectance confocal microscopy (RCM) to diagnose Amelanotic Melanoma. Objectives To validate a new confocal feature, named hyporeflective pagetoid cells (HPCs), for the diagnosis of Amelanotic Melanoma. Methods A group of 20 Amelanotic Melanomas and a control population of nonpigmented melanocytic naevi (10), hypo/nonpigmented nonmelanocytic lesions (20) and pigmented Melanomas (20), imaged by RCM, were retrospectively evaluated. The presence of HPCs and other diagnosis-specific confocal features was assessed and correlated with histopathology. Results HPCs were present, and usually abundant, in the majority of Amelanotic Melanomas (85%). As expected, they were also observed in Spitz naevi. On histopathology, they were correlated with pagetoid infiltration of hypomelanotic melanocytes in all melanocytic lesions. Few nonmelanocytic lesions (three squamous cell carcinomas, two seborrhoeic keratoses and one basal cell carcinoma) showed the presence of HPCs. In these cases, they corresponded to enlarged or dyskeratotic keratinocytes by histopathology. Conclusions The identification of HPCs in the epidermis is a new parameter that is frequently found in Amelanotic Melanoma. Possible confounders are represented by atypical keratinocytes that can be present in nonmelanocytic lesions. However, the whole architecture and the presence of additional diagnostic criteria should be considered in order to obtain a correct diagnosis.
Carola Berking - One of the best experts on this subject based on the ideXlab platform.
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reflectance confocal microscopy in the diagnosis of partially and completely Amelanotic Melanoma report on seven cases
Journal of The European Academy of Dermatology and Venereology, 2013Co-Authors: T Maier, Elke Sattler, Markus Braunfalco, H C Korting, T Ruzicka, Carola BerkingAbstract:Background The clinical diagnosis of Amelanotic Melanoma is often challenging, because the classical clinical and dermoscopic features of pigmented Melanoma are usually missing. The reflectance confocal microscopy (RCM) offers an additional possibility of an in vivo diagnosis of both pigmented and Amelanotic Melanoma lesions. Objectives To test the value of RCM in vivo in the preoperative prediction of Melanoma lesions lacking significant pigment and to compare the results with the evaluation by dermoscopy and histopathology. Methods We examined seven patients with the clinically uncertain differential diagnosis of partially or completely Amelanotic Melanoma by RCM and dermoscopy prior to surgical excision of the lesions according to the previously suggested dermoscopy algorithm and RCM score for Melanoma. The following RCM features were evaluated: major criteria scored +2 (non-edged papillae, cytological atypia at the dermo-epidermal junction) and minor criteria +1 (roundish pagetoid cells, widespread pagetoid infiltration, nucleated cells within dermal papillae, cerebriform cell clusters). The dermoscopic evaluation included the following criteria: polymorphous vessels, dotted and linear irregular vessels, hairpin vessels, pink-erythematous colour, milky red areas, irregularly shaped depigmentation, blue-grey dots and subtle pigmentation. Results The preoperative in vivo RCM analysis revealed common features of Melanoma also found in pigmented Melanoma lesions. All lesions showed a score above three in the applied RCM algorithm which was proposed earlier as the threshold for malignancy. In dermoscopy, five of seven lesions showed characteristic vascular changes. Conclusion In vivo RCM is a valuable tool in the preoperative diagnosis of partially and completely Amelanotic tumours suspicious for Melanoma in addition to dermoscopic evaluation.
Mark J Donaldson - One of the best experts on this subject based on the ideXlab platform.
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primary treatment of choroidal Amelanotic Melanoma with photodynamic therapy
Clinical and Experimental Ophthalmology, 2005Co-Authors: Mark J Donaldson, Lyndell L Lim, Alex C Harper, John Mackenzie, William G CampbellAbstract:The management of choroidal Melanoma involves a delicate balance between preserving vision and preventing metastasis. Plaque brachytherapy has become standard management of most small lesions; however, this can result in radiation retinopathy and optic neuropathy. Transpupillary thermotherapy avoids these side-effects; however, it can also result in visual loss and its effectiveness is limited in Amelanotic lesions. Photodynamic therapy with verteporfin has shown promise in animal studies of choroidal Melanoma, and has recently been used in the management of lesions that have failed to respond to conventional therapy. The authors report a case of primary treatment of a small choroidal Amelanotic Melanoma with photodynamic therapy using verteporfin.