Discussion
Deep endometriosis is the most severe form of endometriosis as it involves infiltration of endometrial-like tissue (endometrial glands, stroma, and related fibrosis) into underlying tissue, organs, musculature, and nerves. Deep endometriosis infiltrates through the peritoneum to a depth greater than 5 mm; however, clinically relevant sequalae arise from the fibrosis, which forms from the chronic bleeding and repair cycles of the endometriotic tissue. 2 Over time, in response to cyclical estrogen and progesterone, deep endometriosis lesions undergo a progression of bleeding, inflammation, and scarring, which, if left untreated, may obstruct or impair the function of adjacent organs and nerves. 2
The true prevalence of deep endometriosis is likely underestimated because of clinicians’ poor understanding of this condition and delays in diagnosis; however, it is estimated to be found in approximately 10% of patients with endometriosis. 3 In addition to the more commonly reported symptoms of pelvic pain and abnormal menstrual bleeding, 4 our patient also presented with difficulty ambulating owing to sciatic nerve involvement, unilateral renal death, and complete bowel obstruction. These latter complications are rare but should be considered among patients with suspected or confirmed endometriosis. As an example, urinary tract endometriosis has been described as a rare entity; however; tract involvement has been reported to be in half (52.6%) of patients undergoing surgical management for deep endometriosis. 5 Nearly all patients with urinary tract endometriosis will have ureteric involvement, which presents with nonspecific symptoms (e.g., cyclical dysuria, hematuria, flank pain, increased urinary frequency). 5 It may also be completely asymptomatic, which may in turn lead to serious complications such as loss of renal function due to ureteric stenosis. 6 This case highlights the importance of pelvic ultrasonography performed by an ultrasonographer and interpreted by an imaging expert (radiologist or gynecologist), both trained to systematically evaluate the urinary tract, in addition to the reproductive tract.
The most recent Canadian clinical practice guideline emphasized the importance of expert guided pelvic ultrasonography, also known as advanced pelvic ultrasonography, and MRI for noninvasive diagnosis and monitoring of endometriosis. 7 Such imaging should be performed and interpreted by imaging experts (radiologists or gynecologists) with the appropriate training to accurately identify ovarian and deep endometriosis. 7 Advanced pelvic ultrasonography is preferred over MRI as the primary investigation for patients with symptoms or signs suggestive of endometriosis. A detailed description of the advanced diagnostic imaging and evaluation of endometriosis was outlined in a 2024 Society of Obstetrics and Gynaecology of Canada (SOGC) Clinical Practice Guideline. 7 Physicians should mention symptoms consistent with endometriosis upon ordering any imaging. If deep endometriosis is suspected, then imaging (ultrasonography or CT) of the kidneys is also recommended to rule out hydronephrosis. Clinicians should order MRI (without contrast initially) if advanced pelvic ultrasonography is not possible or unavailable, and for cases with a high degree of suspicion of ovarian endometriomas and deep endometriosis. Abdominal and pelvic MRI is also preferred for mapping complex lesions that have extrapelvic involvement. 7 As outlined in the Canadian guideline, access to advanced pelvic ultrasonography for endometriosis is currently limited across Canada. Adoption of this imaging across the country should be encouraged by all those who provide pelvic imaging for female patients. 7
The SOGC endometriosis guideline also emphasized that management of endometriosis should be personalized and centred on the priorities of the patient. 8 Considerations for plan of care should include pain management, fertility preservation, and future family planning. This may involve a multimodal and interdisciplinary treatment approach, which could include surgical excision, hormonal treatments, analgesics, or alternative nonpharmacologic interventions. However, upon suspicion or detection of deep endometriosis, referral to fellowship-trained experts in minimally invasive surgery should be considered for evaluation and care, particularly if primary medical options are not effective. 7 , 8
In our case, the patient’s primary goal was pain management. She was started on dienogest (a synthetic progestin) followed by leuprolide acetate (a GnRH agonist). Used as a second-line treatment, GnRH agonists suppress systemic estrogen levels and impede the stimulus for the proliferation of endometriosis, resulting in disease regression and symptom suppression. Response rates vary, and the treatment results in menopausal symptoms, which limits its tolerability and safety. 8 The combination of GnRH agonists with hormonal add-back therapy, a low-dose hormonal replacement (usually estrogen, progestin, or both) is recommended to minimize vasomotor symptoms and bone loss among patients who require the treatment long term. 8
In our patient, deep endometriosis involved multiple organs and resulted in renal death, bowel obstruction, and pain with walking. Medical management reduced the volume of disease, thereby improving this patient’s symptoms and quality of life. Multidisciplinary collaboration and the use of advanced imaging techniques provided a team-based approach to care planning and disease monitoring.
The section Cases presents brief case reports that convey clear, practical lessons. Preference is given to common presentations of important rare conditions, and important unusual presentations of common problems. Articles start with a case presentation (500 words maximum), and a discussion of the underlying condition follows (1000 words maximum). Visual elements (e.g., tables of the differential diagnosis, clinical features or diagnostic approach) are encouraged. Consent from patients for publication of their story is a necessity. See information for authors at www.cmaj.ca .