BACKGROUND Fibrosis in the peripheral nerve is the end stage of leprous neuropathy and the cause of the resulting permanent neural function impairments. Preventive measures to avoid this irreversible pathological state are a relief strategy for leprosy sufferers. OBJECTIVES The present study describes the frequency of fibrosis along with its characterisation and pathogenic development. METHODS Six-hundred-and-thirteen nerve samples were sorted from 278 neural leprosy (NL) and 335 non-leprosy neuropathy patients (ON). The total number of samples was histologically examined by routine staining methods (haematoxylin-eosin, Wade staining and Gomori’s trichrome) and fibrosis was evaluated via semi-quantitative estimation. FINDINGS Fibrosis was most frequent in the NL group (33% against 0.4% in ON) while fibrosis in association with endoneurial microfasciculation was found in 38 (41.3%) of the NL samples in the examination of semithin sections. Pericytic activation in the perivascular environment was confirmed to be the source of the fibroblasts and perineurial cells delimiting microfascicles. End-stage fibrosis in leprosy displays an arrangement of microfascicles devoid of neural components (i.e., Schwann cells and axons) lined by an intermediate phenotype of fibroblastic-perineurial cells filled with bundles of collagen fibres. MAIN CONCLUSIONS The present study underscores that fibrosis is frequently the severe end stage of neural leprosy NL pathogeny after analysing the notably distinct development of fibrosis within the neural environment.

FUNDAMENTOS: As neoplasias malignas da pele de grandes dimensões apresentam dificuldades de reconstrução após a excisão. OBJETIVO: O objetivo deste estudo foi avaliar a exeqüibilidade de uma nova proposta de cobertura para feridas cirúrgicas criadas após a ressecção de grandes tumores cutâneos, a combinação da derme acelular humana com epitélio autólogo cultivado. MÉTODOS: A aplicação dos substitutos de pele foi feita em quatro pacientes com área de implante variando de 33 a 120 cm2. Além da observação dos resultados clínicos, realizou-se estudo morfológico para avaliação da integração dos implantes. RESULTADOS: Ceratinócitos autólogos cultivados foram enxertados em dois pacientes e não demonstraram integração. A derme acelular foi aplicada em quatro pacientes, sendo que em um deles foram feitas duas aplicações. Dos cinco implantes de derme acelular realizados, dois não apresentaram integração, em dois a integração foi de 70%, e de 50% no último. CONCLUSÃO: A cobertura imediata e definitiva de defeitos cirúrgicos através da aplicação de derme acelular humana combinada com epitélio autólogo cultivado é exeqüível. Em oncologia cutânea apenas em situações especiais o uso de substitutos de pele pode ser conveniente no sentido de evitar reconstruções mais complexas.

BACKGROUND: Reconstruction difficulties may arise after excision of large malignant skin neoplasms.a OBJECTIVE: The objective of this study was to assess the feasibility of a new coverage for surgical wounds following resection of large skin tumors: a combination of human acellular dermis with cultured autologous epithelium. METHODS: The skin substitute was implanted in four patients, one of them received two implants and the area ranged from 33 to 120 cm2. Clinical results and morphologic studies were assessed as to implant integration. RESULTS: Cultured autologous epithelium was grafted in two patients and no integration was observed. The acellular dermis was applied to four patients. Out of five acellular dermis implants, two did not present integration, two presented 70% integration and the remaining, 50% integration. CONCLUSION: The immediate and definite coverage of surgical defects by means of application of human acellular dermis combined with cultured autologous epithelium is feasible. In skin oncology, the use of skin substitutes might be convenient only in special situations to avoid more complex reconstructions.