Microsatellite instability in benign skin lesions in hereditary non-polyposis colorectal cancer syndrome.

The coexistence of cutaneous and extra-cutaneous malignancies within one family could be explained by shared genetic mechanisms such as common tumor suppressor gene mutations or oncogene activation, as well as mutations in DNA repair genes. Hereditary non-polyposis colorectal cancer syndrome (HNPCC) and its variant Muir-Torre syndrome (MTS) are caused by germline DNA mismatch repair gene mutations. Colonic and endometrial tumors from HNPCC patients exhibit microsatellite instability (MSI), as do sebaceous lesions in MTS. We recruited individuals from cancer prone families to determine if MSI is found in benign and malignant skin lesions and to assess whether MSI in the skin is predictive of genomic instability with susceptibility to tumors characteristic of HNPCC. One hundred and fifteen benign, dysplastic, and malignant skin lesions from 39 cancer prone families were analyzed. Thirteen benign skin lesions from three individuals belonging to two HNPCC pedigrees showed MSI. No mutations in hMSH2 and hMLH1 were found in two of the three individuals with RER + skin lesions. We found MSI in non-sebaceous non-dysplastic skin lesions in HNPCC pedigrees. MSI was not found in skin lesions within other family cancer syndromes. These results have important clinical implications as the detection of MSI in prevalent readily accessible skin lesions could form the basis of noninvasive screening for HNPCC families. It may also be a valuable tool in the search for new mismatch repair genes

Pioderma gangrenoso: apresentação atípica Pyoderma gangrenosum: an atypical presentation

O pioderma gangrenoso é doença neutrofílica rara, de etiologia incerta e que se associa a doenças sistêmicas em 50% dos casos. Relata-se um caso de pioderma gangrenoso com apresentação atípica em um homem de 39 anos com psoríase associada e ótima resposta à ciclosporina. Este relato de caso aborda as diversas formas clínicas da doença, a dificuldade diagnóstica e as opções terapêuticas atualmente disponíveis.<br>Pyoderma gangrenosum is a rare neutrophilic disease of unknown origin that is associated with systemic diseases in 50% of cases. We report a case of atypical pyoderma gangrenosum in a 39- year-old man with psoriasis associated and optimal response to cyclosporin. This case report shows the diversity of clinical manifestations of this disease, the difficult diagnosis and the therapeutic options currently available