“…Immunohistochemistry has been performed in 29 cases, always showing the usual immunohistochemical profile of mesothelial cells, including strong immunoreactivity for cytokeratin (pankeratin, high-molecular weight cytokeratin 5/6) and calretinin. Ultrastructural analysis has been used in 10 cases, 8,9,11,14,16,18,21,30 in all of which the classical microvilli of coelomic type were always observed, these being the substrate of the ''brush'' border some people were able to observe and depict even on hematoxylin and eosin stained slides in mesothelial derived tumors, including AT-AG. 10 In all cases the AT-AG was totally resected (either by laparoscopic or open surgery), except for 1 (case 34, Table 1) where the diagnosis was made on core biopsy and the lesion was left for follow-up.…”