Nuck canal endometriosis: MR imaging findings and clinical features

The purpose of this study was to describe the MR imaging findings of Nuck canal endometriosis (NCE). In a 10-year period, 486 out of 612 patients, with laparoscopically and/or surgically proven diagnosis of pelvic endometriosis, underwent MR imaging examination. The examinations were reviewed by two urogenital experienced radiologists working in consensus. Data analysis included: lesions location, size, morphological and signal intensity pattern, involvement of the adjacent muscles, and tendons. In 372 out of 486 patients an MRI diagnosis of endometriosis was made. NCE was found in eight patients. All the lesions were located on the right side. The mean size of the lesions was 2.5 cm (range 1.5-4.5 cm). Two patterns of NCE were found: type 1, prevalently cystic (n = 2); and type 2, prevalently solid with small scattered cysts within lesion (n = 6). In all the patients, hemorrhagic hyperintense cysts could be seen on T1-weighted images. In four patients, the lesions involved the inguinal canal, and in another four patients, the lesions were only outside the inguinal canal. Involvement of the abdominis rectus muscle was seen in two patients, and of the adductor common tendon in two patients. MR imaging permits the diagnosis of NCE as well as the evaluation of exact extension of the disease.