Com os objetivos de conhecer melhor a morfologia do megacólon chagásico e contribuir para o conhecimento da patogênese da fibrose dos megas, realizou-se estudo morfométrico na muscular circular do cólon, contando-se o número de mastócitos e medindo o conjuntivo fibroso nessa camada. Foram avaliados anéis do sigmóide distal de 15 chagásicos com megacólon (MCC), 15 sem megacólon (CSMC) e 15 não chagásicos (NC). Os anéis foram fixados em formol, incluídos em parafina, cortados com 7mm de espessura e corados por Azan-Heidenhain e Giemsa. O número de mastócitos e a fibrose foram maiores no grupo com MCC em relação ao CSMC e NC (p < 0,05; teste de Kruskal-Wallis); não houve diferença significante entre os dois últimos grupos. Diante destes achados, é possível, que haja relação entre mastocitose e fibrose no megacólon chagásico, como já se demonstrou em outras doenças.

A morphometric study of the circular colon musculature was performed, in which the mast cell count was determined and the connective fibrous tissue in this layer was measured. The objective was to gain better understanding of Chagas megacolon morphology and contribute towards the knowledge of fibrosis pathogenesis in Chagas megas. An evaluation was made of 15 distal sigmoid rings from Chagas patients with megacolon (MCC), 15 without megacolon (CSMC) and 15 non-Chagas patients (NC). The rings were fixed in formol, embedded in paraffin, and 7mm thick sections were cut and stained using Azan-Heidenhain and Giemsa. The mast cell count and fibrosis were greater in the MCC group than in the CSMC and NC groups (p < 0.05; Kruskal-Wallis test) and there was no significant difference between the latter two. The fibrosis and increased mast cell count in the colon musculature of the MCC group possibly indicates that there is a relationship between mastocytosis and fibrosis, as has already been demonstrated in other pathologies.