A 47-year-old woman was referred to the gynecology office by her primary care NP for surgical excision of an enlarging nodule on the right side of her mons pubis. Onset occurred about 6 months earlier. The patient reported that symptoms waxed and waned but had worsened progressively over the past 2 to 3 months, adding that the nodule hurt only occasionally. She noted that symptoms were exacerbated by exercise, specifically running. Further questioning prompted the observation that her symptoms were more noticeable at the time of menses.
The patient’s medical history was unremarkable, with no chronic conditions; her surgical history consisted of a wisdom tooth extraction. She had no known drug allergies. Her family history included cerebrovascular accident, hypertension, and arthritis. Reproductive history revealed that she was G1 P1, with a 38-week uncomplicated vaginal delivery. She experienced menarche at age 14, and her menses was regular at every 28 days. For the past 5 days, there had been no dysmenorrhea. The patient was married, exercised regularly, and did not use tobacco, alcohol, or illicit drugs.
On examination, the patient’s blood pressure was 123/73 mm Hg; heart rate, 77 beats/min; respiratory rate, 12 breaths/min; weight, 128 lb; height, 5 ft 7 in; O2 saturation, 99% on room air; and BMI, 20. The patient was alert and oriented to person, place, and time. She was thin, appeared physically fit, and exhibited no signs of distress. Her physical exam was unremarkable, apart from a firm, minimally tender, well-circumscribed, 3.5 × 3.5–cm nodule right of midline on the mons pubis.
The patient was scheduled for outpatient surgical excision of a benign skin lesion (excluding skin tags) of the genitalia, 3.1 to 3.5 cm (CPT code 11424). During this procedure, it became evident that this was not a lipoma. The lesion was exceptionally hard, and it was difficult to discern if it was incorporated into the rectus abdominis near the point of attachment to the pubic symphysis. The lesion was unintentionally disrupted, revealing black powdery material within the capsule. The tissue was sent for a fast, frozen section that showed “soft tissue with extensive involvement by endometriosis.” The pathology report noted “[m]any endometrial glands in a background of stromal tissue. Necrosis was not a feature. No evidence of atypia.” The patient’s postoperative diagnosis was endometriosis.
Endometriosis occurs when endometrial or “endometrial-like” tissue is displaced to sites other than within the uterus. It is most frequently found on tissues close to the uterus, such as the ovaries or pelvic peritoneum. Estrogen is the driving force that feeds the endometrium, causing it to proliferate, whether inside or outside the uterus. Given this dependence on hormones, endometriosis occurs most often during a woman’s fertile years, although it can occur after menopause. Endometriosis is common, affecting at least 10% of premenopausal women; moreover, it is identified as the cause in 70% of all female chronic pelvic pain cases.1-4
Endometriosis has certain identifiable features, such as chronic pain, dyspareunia, infertility, and menstrual and gastrointestinal symptoms. However, it is seldom diagnosed quickly; studies indicate that diagnosis can be delayed by 5 to 10 years after a patient has first sought treatment for symptoms.2,4 Multiple factors contribute to a lag in diagnosis: Presentation is not always straightforward. There are no definitive lab values or biomarkers. Symptoms vary from patient to patient, as do clinical skills from one diagnostician to another.1
Unlike pelvic endometriosis, inguinal endometriosis is not common; disease in this location encompasses only 0.3% to 0.6% of all diagnosed cases.3,5-7 Since the discovery of the first known case of round ligament endometriosis in 1896, there have been only 70 cases reported in the medical literature.6,7