Extragenital endometriosis: assessment with MR imaging. A pictorial review

Abstract

Endometriosis is a gynaecologic disease characterized by endometrial tissue outside the uterine cavity. Commonly it affects the pelvic organs. When endometrial nodules or plaques are localized in sites other than the uterus or ovaries, it is termed extragenital endometriosis. Adequate pre-operative assessment is essential for treatment planning. MRI is a non-invasive method with high spatial resolution that allows the multiplanar evaluation of genital and extragenital endometriosis. Herein, we present a pictorial review of a variety of extragenital endometriosis cases, all of which can be encountered in clinical practice.

Figure 1.

Axial T₂ weighted (a) and fat-saturated T₁ weighted (b) images. Large fibrotic and haemorrhagic endometrial localization (arrow) in the middle and lateral portion of the right round ligament infiltrating the oblique muscle and the T₁ weighted sequence (black arrowheads).

Figure 2.

Axial T₂ weighted image. Retracting endometrial lesion (arrows) of the left uterosacral ligament, with involvement of the piriformis muscle and the lateral wall of the rectus.

Figure 3.

Axial T₂ weighted image. Hypointense endometrial lesion (arrows), with invasion and retraction of the anterior wall of the left colon and of the caecum wall, which is dislocated in the Douglas' pouch. The fat plane is obscured.

Figure 4.

Axial fat-saturated T₁ weighted image without contrast (a), diffusion-weighted image (b = 900) (b) and apparent diffusion coefficient map (c). Endometrial lesion of the right ovary characterized by the presence of blood (arrow); the mass has no specific slightly restricted diffusion water movement.

Figure 5.

Axial T₂ weighted (a) and fat-saturated pre-contrast T₁ weighted (b) images. Coronal (c) and axial (d) fat-saturated T₁ weighted images after the injection of gadolinium contrast media. A 28-year-old patient, with catamenial sciatic pain. Endometrial nodular lesion of the left sciatic nerve (arrows), characterized by hypointense signal with hyperintense foci on the T₂ weighted image. Notice the oedema of the piriformis muscle (arrowheads). After contrast injection, there is enhancement of the piriformis muscle due to inflammation, clearly seen in the coronal image compared with the contralateral.

Figure 6.

Axial T₂ weighted (a) and fat-saturated T₁ (b) weighted images. Exophytic endometrial lesion (arrows) of the posterior bladder wall, showing lobulated margins, low signal in T₂ weighted image and very high signal blood foci in the T₁ weighted image sequence.

Figure 7.

Coronal fat-saturated T₁ weighted image (a), sagittal (b) and coronal (c) T₂ weighted images. Fibrotic and haemorrhagic endometrial nodule (arrows) in the abdominal wall affecting both rectus muscles, arising from the scar of the previous C-section.

Figure 8.

Axial (a) and coronal (b) T₂ weighted images. Small bowel endometrial lesion (arrows), with hypointense signal. The lesion grows in the lumen of the bowel with partial obstruction. In the coronal view, the hypointense vertical lines (arrowheads) represent retracting fibrotic strands.

Figure 9.

Axial (a) and sagittal (b) T₂ weighted images. Retracting endometrial lesion (arrows), located in the lower portion of the right obturator region, anteriorly to the piriformis muscle. The nodule has a stellate shape with undefined margins, and the right ureter (u) is obstructed with consequent hydroureteronephrosis.

Figure 10.

Axial fat-saturated T₁ weighted image (a), axial (b) and sagittal (c) T₂ weighted images. 45-year-old patient, operated for severe pelvic endometriosis (hysterectomy). Solid round-shaped lesion of the bladder neck-first segment of the urethra (arrows), showing high signal in the T₁ weighted sequence and intermediate signal in the T₂ weighted sequences.

Figure 11.

Axial T₂ weighted (a) and fat-saturated T₁ weighted images (b). A 33-year-old patient, with pelvic pain and catamenial haematochezia. Typical “mushroom cup” appearance (arrows) of a stenotic endometrial lesion of the sigma; the wall is irregularly thickened with hypointense signal and some hyperintense foci in the T₂ weighted image. Diffusion-weighted image (b = 900) (c) and apparent diffusion coefficient map (d) showing a slightly restricted movement of water, not specific but consistent with an endometrial lesion as proved after surgery.

Figure 12.

Axial (a) and sagittal (b) fat-saturated T₁ weighted image. 30-year-old patient complaining about dysmenorrhoea and upper abdominal pain, which travelled to the right shoulder. Multiple endometrial lesions of the diaphragm (arrows); the nodules are characterized by a hyperintense signal in the fat-saturated T₁ weighted sequences owing to the presence of blood.

Figure 13.

Sagittal T₂ weighted (a) and fat-saturated T₁ weighted (b) images. A 29-year-old patient, with catamenial bleeding from the navel. Haemorrhagic endometrial lesion located at the navel (arrows). In the anterior wall of the uterus, there is a round-shaped hypointense subserosal fibroid.

Figure 14.

Coronal T₂ weighted image. A 35-year-old patient with chronic pelvic pain. Severe endometrial lesions of the ovaries. The MRI scan showed unspecific multiple lobulated lymph nodes >15 mm (arrows): based on the presence of endometriomas, an additional endometrial localization was supposed, but malignancies could not be excluded. After surgical removal, the lymph nodes proved positive for endometriosis.

Figure 15.

Axial T₂ weighted image (a), axial (b) and sagittal (c) fat-saturated T₁ weighted images. A 32-year-old patient, operated on numerous times for severe pelvic endometriosis (hysterectomy); the patient complained about right catamenial claudication. In (a) and (b), the intracanal root of the right nerve S3 (arrows) is enlarged, with hypointense signal in the T₂ weighted sequence and very high signal in the T₁ weighted sequence. Even the extracanal portion of S3 (arrowheads) is enlarged with very high signal.