The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
M Bonczkowitz - One of the best experts on this subject based on the ideXlab platform.
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Pigmented Atypical Fibroxanthoma.
Histopathology, 1998Co-Authors: C Diaz-cascajo, S Borghi, M BonczkowitzAbstract:Aim: The purpose of this report is to call attention to a pigmented variant of Atypical Fibroxanthoma that resembles malignant melanoma, both clinically and histopathologically. Methods and results Thirty-eight cases of Atypical Fibroxanthoma were examined for the presence of pigmented areas. Four such cases were found. Neoplastic cells showed erythrophagocytosis and accumulation of haemosiderin pigment in the cytoplasm. In three cases, immunohistochemical studies using a battery of antibodies were performed. Neoplastic cells were strongly positive for vimentin and weakly positive for CD68, whereas they were negative for melanocytic markers, including S100 protein, HMB45, and the monoclonal antibody NK1-C3 to melanoma-associated antigen. Conclusions Pigmented Atypical Fibroxanthoma represents a poorly recognized variant of the neoplasm that may be easily misinterpreted as malignant melanoma. To the best of our knowledge, this is the first report of erythrophagocytosis in Atypical Fibroxanthoma.
Christopher D M Fletcher - One of the best experts on this subject based on the ideXlab platform.
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ultraviolet induced p53 mutations in Atypical Fibroxanthoma
American Journal of Pathology, 1994Co-Authors: A Dei P Tos, Roberta Maestro, Claudio Doglioni, Daniela Gasparotto, M Boiocchi, Licia Laurino, Christopher D M FletcherAbstract:Atypical Fibroxanthoma (AFX) is an uncommon neoplasm of the superficial soft tissue occurring in actinically damaged skin of elderly patients. Sun-exposed skin also represents the main site of squamous and basal cell carcinomas and malignant melanoma, and a key role for ultraviolet (UV) radiation in their pathogenesis has long been suspected. UV-related mutations of the p53 gene have been identified in human skin cancers. To verify whether the pathogenesis of AFX is related to the effect of sunlight, p53 protein and gene status have been investigated in a series of 10 cases of AFX. Seven of 10 showed p53 immunoreactivity in most of the neoplastic cells. Molecular analysis of the p53 gene revealed an abnormal single strand conformation polymorphism pattern in all the p53 positive cases. Polymerase chain reaction direct sequencing revealed that all the mutations involved cytosine bases. Four cases showed C to T transitions (including two CC-TT double base substitutions) and two cases showed C to G transversion. All but one mutation took place at dipyrimidine sites. These findings provide the first objective evidence for the central role of UV radiation in the development of AFX and also represent the first in vivo demonstration of solar UV-induced mutations in a human mesenchymal neoplasm.
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spindle cell non pleomorphic Atypical Fibroxanthoma analysis of a series and delineation of a distinctive variant
Histopathology, 1993Co-Authors: Eduardo Calonje, Catherine Wadden, Edward Wilsonjones, Christopher D M FletcherAbstract:Atypical Fibroxanthoma is a bizarre, cytologically malignant but usually clinically benign, lesion which typically arises in sun-damaged skin of the head and neck region in the elderly. Classically, its morphology is said to represent the dermal counterpart of pleomorphic malignant fibrous histiocytoma. We have identified 10 cases of a more monomorphic spindle-celled, fascicular variant which, paradoxically, was often mistaken for a clinically malignant lesion because it lacked the pleomorphism of conventional Atypical Fibroxanthoma. These tumours all arose in the head and neck region as polypoid lesions in the elderly. The tumours were confined to the dermis, often had an epidermal collarette, showed an eosinophilic fascicular morphology and were highly mitotic. All 10 were vimentin positive and five showed very focal actin positivity. Desmin, keratin and S-100 protein were negative in all cases. The clinical course was benign in all cases, justifying their accurate recognition. The principal differential diagnoses are spindle cell squamous carcinoma, spindle cell melanoma and leiomyosarcoma. Immunohistochemistry plays a key role in this distinction.
Antje Sucker - One of the best experts on this subject based on the ideXlab platform.
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Atypical Fibroxanthoma and pleomorphic dermal sarcoma harbor frequent notch1 2 and fat1 mutations and similar dna copy number alteration profiles
Modern Pathology, 2018Co-Authors: Klaus G Griewank, Thomas Wiesner, Rajmohan Murali, Carina Pischler, Hansgeorg Müller, Christian Koelsche, Inga Möller, Cindy Franklin, Ioana Cosgarea, Antje SuckerAbstract:Atypical Fibroxanthomas and pleomorphic dermal sarcomas are tumors arising in sun-damaged skin of elderly patients. They have differing prognoses and are currently distinguished using histological criteria, such as invasion of deeper tissue structures, necrosis and lymphovascular or perineural invasion. To investigate the as-yet poorly understood genetics of these tumors, 41 Atypical Fibroxanthomas and 40 pleomorphic dermal sarcomas were subjected to targeted next-generation sequencing approaches as well as DNA copy number analysis by comparative genomic hybridization. In an analysis of the entire coding region of 341 oncogenes and tumor suppressor genes in 13 Atypical Fibroxanthomas using an established hybridization-based next-generation sequencing approach, we found that these tumors harbor a large number of mutations. Gene alterations were identified in more than half of the analyzed samples in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter. The presence of these alterations was verified in 26 Atypical Fibroxanthoma and 35 pleomorphic dermal sarcoma samples by targeted amplicon-based next-generation sequencing. Similar mutation profiles in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter were identified in both Atypical Fibroxanthoma and pleomorphic dermal sarcoma. Activating RAS mutations (G12 and G13) identified in 3 pleomorphic dermal sarcoma were not found in Atypical Fibroxanthoma. Comprehensive DNA copy number analysis demonstrated a wide array of different copy number gains and losses, with similar profiles in Atypical Fibroxanthoma and pleomorphic dermal sarcoma. In summary, Atypical Fibroxanthoma and pleomorphic dermal sarcoma are highly mutated tumors with recurrent mutations in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter, and a range of DNA copy number alterations. These findings suggest that Atypical Fibroxanthomas and pleomorphic dermal sarcomas are genetically related, potentially representing two ends of a common tumor spectrum and distinguishing these entities is at present still best performed using histological criteria.
Leslie Robinsonbostom - One of the best experts on this subject based on the ideXlab platform.
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squamous cell carcinoma detected by high molecular weight cytokeratin immunostaining mimicking Atypical Fibroxanthoma
Archives of Pathology & Laboratory Medicine, 2001Co-Authors: Yulia Gray, Henry J Robidoux, David S Farrell, Leslie RobinsonbostomAbstract:Abstract Atypical Fibroxanthoma can mimic other tumors, particularly spindle cell squamous cell carcinoma and spindle cell or desmoplastic melanoma. We describe a patient with chronic lymphocytic l...
Serdar Ugras - One of the best experts on this subject based on the ideXlab platform.
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Atypical Fibroxanthoma of the skin and the lower lip in xeroderma pigmentosum
British Journal of Dermatology, 2000Co-Authors: Fatma Husniye Dilek, Nusret Akpolat, Ahmet Metin, Serdar UgrasAbstract:Xeroderma pigmentosum (XP) is a rare, usually autosomal recessive disorder related to DNA repair defects. Atypical Fibroxanthoma (AFX) is a pleomorphic tumour that occurs infrequently on the limbs and trunk in children. We report a child with XP who presented with AFX of the facial skin and the lower lip. The diagnosis of AFX was confirmed using histological and immunohistochemical techniques. We discuss the possibility that ultraviolet-induced damage might be implicated in the pathogenesis of AFX.
