RESUMO
BACKGROUND: An acute abdomen is an emergency that requires accurate diagnosis and prompt treatment. In pregnancy, the process is even more challenging and sometimes the radiological findings are unclear. Moreover, endometriosis- related complications are rare, especially in previously unknown endometriosis. CASE PRESENTATION: We report on a case of acute endometriosis-related sigmoid perforation during pregnancy (34 weeks of gestation) due to a previously unknown deep intestinal infiltrating endometriosis with focal ulceration of the affected colonic mucosa. CONCLUSIONS: Despite the low relative risk, clinicians should be aware of possible endometriosis-associated complications in pregnancy with potentially life-threatening events, even in previously unknown endometriosis. Further studies should evaluate intestinal complications during pregnancy in relation to previous treatment of intestinal endometriosis (conservative vs. surgical).