Background: Extramedullary hematopoiesis depends on complex pathophysiological mechanisms linked to hematopoietic stem cells and the proteins considered mediators of the inflammation. The identification of hematopoietic cells outside bone marrow in the adult is an occurrence that can occasionally follows the inflammatory response, was considered a secondary occurrence, but current biomolecular studies have changed that concept. Aim: Describe the presence of clusters of precursor cells of platelets (megakaryocytes), and cells of the inflammatory response in the abdominal wall and spleen of rats with experimentally induced incisional hernias and repaired with different synthetic prostheses. Methods: Twenty-five rats with incisional hernias previously performed, were divided into groups of five animals each: Group 1, repair of the hernia defect without prosthetic implant; Group 2, repair with polypropylene prosthesis; Group 3, repair using polypropylene with low weight; Group 4, the use of polypropylene and polyglecaprone prosthesis; Group 5, of polypropylene and polyglactin prosthesis. All prostheses were cut in rhombus format with area 2,625 cm². The animals were reoperated after 10 days, the abdominal walls were removed with the viscera attached to them and the material was processed for histological study. Results: Megakaryocyte niches in the abdominal wall and spleen, occasionally removed together with the adhesions produced in animals with implantation of prostheses and significant inflammatory reaction. Conclusion: The intense inflammatory reaction due to the prostheses with polypropylene in their composition was disproportionate to the expected response, indicating that further studies should be accomplished including immunophenotyping evaluation and specific panels of monoclonal antibodies to better understand the findings.

Os cistos epidermóides, também denominados cistos cutâneos, são tumores muito freqüentes, que podem requere cuidados cirúrgicos. Na maioria das vezes, em razão da apresentação clínica patognomônica e de curso indolente, são simplesmente removidos. Habitualmente, o diagnóstico clínico é de fácil confirmação na cirurgia devido ao aspecto típico de formação cística preenchida com um fluido cremoso. Comumente tais lesões “típicas” não sofrem investigação histológica após a remoção. Entretanto, este relato de caso de um cisto epidérmico em couro cabeludo vai mais além, produzindo, por meio de técnicas laboratoriais de rotina, uma análise histopatológica, que revelou a existência de um cisto típico, esférico e esbranquiçado, preenchido, predominantemente, pro lâminas de queratina, delimitado por um epitélio estratificado e envolvido por uma cápsula de tecido conjuntivo denso modelado.