An unusual case of large endometrioma within the rectus abdominis muscle misdiagnosed as desmoid tumour.

We describe an unusual case of giant intramuscular abdominal endometrioma clinically misdiagnosed as desmoid tumour in a 36-year-old female patient with a one-year history of lower abdominal pain. Endometriosis is defined by the presence of endometrial tissue outside the uterine cavity, associated with fibrosis and inflammatory reaction. Although the abdominal wall is one of the most frequent sites of extra pelvic endometriosis, the localization in the anterior rectus abdominis muscle is unusual and associated with previous cesarean section. In most cases, the preoperative diagnosis is erroneous because the different imaging modalities are nonspecific but only useful in determining the extent of disease and in the planning of operative resection. A better acquaintance with the imaging presentation of abdominal wall endometriosis holds the potential of positively impact disease confirmation and may play a crucial role in the face of innovation in treatment. KEY WORDS: Desmoid tumour, Endometrioma, Surgery.