Suppression of an accessory and cavitated uterine mass with norethindrone: a case report.

The patient initially presented as a 16-year-old. She had no past medical surgical or relevant family history. She reported menses starting at the age of 11 years with increasing pain over the past 5 years. Her menses lasted 7–8 days, and with it, she would experience a week of excruciating pain requiring opiates for relief. Her pain with menses caused her to miss multiple days of school with each cycle. For her initial workup, pelvic ultrasound was performed, which showed a cystic area in the left myometrium. For better characterization, MRI was performed, which revealed a 4.1 × 3.9 × 3.5-cm cavitary lesion in the left myometrium with rim of lesion of similar enhancement to the junctional zone and central portion hypodense, consistent with blood products ( Fig. 1 ). These findings were highly suspicious for an ACUM. Of note, there were no abnormalities noted in the kidneys on her MRI. Figure 1 Initial diagnostic magnetic resonance imaging. ( A ) T2-weighted sagittal image, unaffected endometrium noted with arrows. ( B) T2-weighted sagittal image, accessory and cavitated uterine mass (ACUM) seen with bright menstrual products noted in the cavity. ( C ) T2-weighted axial image, ACUM circled, unaffected endometrium noted with arrows. ( D ) T2-weighted axial image, ACUM seen with bright menstrual products noted in the cavity ( E ) Volumetric Interpolated Breath-Hold Examination (VIBE) coronal image, ACUM seen with bright menstrual products noted in the cavity. ( F ) VIBE axial image, ACUM seen with bright menstrual products noted in the cavity, unaffected endometrium noted with arrows. Initial diagnostic magnetic resonance imaging. ( A ) T2-weighted sagittal image, unaffected endometrium noted with arrows. ( B) T2-weighted sagittal image, accessory and cavitated uterine mass (ACUM) seen with bright menstrual products noted in the cavity. ( C ) T2-weighted axial image, ACUM circled, unaffected endometrium noted with arrows. ( D ) T2-weighted axial image, ACUM seen with bright menstrual products noted in the cavity ( E ) Volumetric Interpolated Breath-Hold Examination (VIBE) coronal image, ACUM seen with bright menstrual products noted in the cavity. ( F ) VIBE axial image, ACUM seen with bright menstrual products noted in the cavity, unaffected endometrium noted with arrows. She was started on norethindrone acetate (5 mg orally once a day). Her periods were suppressed on this initial dose, and her pain resolved. She was offered definitive management with surgical intervention. The risks and benefits of surgical management were discussed with the patient; however, the patient declined. She wanted to avoid missing more of her high school classes and sports practices due to downtime after surgery. A discussion with the patient was performed that if the norethindrone acetate continued to cure her pain, she could continue with conservative management, as well as the need for eventual surgical management if the patient desired childbearing in the future. A year later, when she was aged 17 years, she continued to be pain-free and fully asymptomatic on the norethindrone. Repeat MRI showed that her ACUM shrunk in size to 3.4 × 2.8 × 2.7 cm ( Fig. 2 ). Then, at the age of 18 years, transabdominal ultrasound was performed for surveillance, which showed that it further decreased in size to 2.8 × 2.4 × 2.4 cm ( Fig. 3 ). Figure 2 Repeat surveillance magnetic resonance imaging after 1 year of norethindrone use. ( A ) T2-weighted sagittal image, unaffected endometrium noted with arrows. ( B ) T2-weighted sagittal image, accessory and cavitated uterine mass (ACUM) seen with dark menstrual products noted in the cavity. ( C ) T2-weighted coronal image, unaffected bright endometrium noted with arrows, ACUM seen with dark menstrual products noted in the cavity. ( D ) T2-weighted axial image, unaffected bright endometrium noted with arrows, ACUM seen with dark menstrual products noted in cavity. ( E ) Volumetric Interpolated Breath-Hold Examination (VIBE) axial image, ACUM seen with bright menstrual products noted in the cavity, unaffected endometrium noted with arrows. ( F ) T1-weighted axial image, ACUM seen with bright menstrual products noted in the cavity. Figure 3 Repeat surveillance ultrasound after 2 years of norethindrone use. ( A ) Uterus seen in transverse view, accessory and cavitated uterine mass marked on image. ( B ) Uterus seen in sagittal view, accessory and cavitated uterine mass marked on image. ( C ) Unaffected endometrium in sagittal view, marked on image. Repeat surveillance magnetic resonance imaging after 1 year of norethindrone use. ( A ) T2-weighted sagittal image, unaffected endometrium noted with arrows. ( B ) T2-weighted sagittal image, accessory and cavitated uterine mass (ACUM) seen with dark menstrual products noted in the cavity. ( C ) T2-weighted coronal image, unaffected bright endometrium noted with arrows, ACUM seen with dark menstrual products noted in the cavity. ( D ) T2-weighted axial image, unaffected bright endometrium noted with arrows, ACUM seen with dark menstrual products noted in cavity. ( E ) Volumetric Interpolated Breath-Hold Examination (VIBE) axial image, ACUM seen with bright menstrual products noted in the cavity, unaffected endometrium noted with arrows. ( F ) T1-weighted axial image, ACUM seen with bright menstrual products noted in the cavity. Repeat surveillance ultrasound after 2 years of norethindrone use. ( A ) Uterus seen in transverse view, accessory and cavitated uterine mass marked on image. ( B ) Uterus seen in sagittal view, accessory and cavitated uterine mass marked on image. ( C ) Unaffected endometrium in sagittal view, marked on image. After 4 years of conservative management, the patient requested definitive surgical management at the age of 20 years during the winter break of her sophomore year of college. She reported that her pain continued to be absent on norethisterone acetate. Decision was made to use an open approach to minimize uterine damage because it would be easier to better locate the dissection plane between the ACUM and normal myometrium and allow for better closure of the uterine myometrium. In preparation of surgery, patient was instructed to stop the norethindrone acetate 8 weeks preoperatively to allow the ACUM to refill with two cycles worth of menstrual products so it would be easier to locate at the time of the operation. The patient underwent uncomplicated laparotomy 4 years after her initial diagnosis via Pfannenstiel skin incision. A small uterus was appreciated with a 3-cm palpable mass on the left side of the uterus. The uterus otherwise appeared normal with both fallopian tubes appropriately entering the uterine fundus. The mass was incised and then excised ( Fig. 4 and Supplemental Fig. 1 , available online). The central cavity was noted to be filled with hemosiderin and dark-brown blood. The myometrium was then closed in two layers. The deepest layer was closed in a running unlocked fashion. The serosal layer was closed using a baseball stitch. The total estimated blood loss for the case was 50 mL. She was discharged on postoperative day 2 after meeting all postoperative milestones. Pathology from the procedure confirmed the diagnosis of ACUM. Of note, no entry into the uterine cavity was performed, allowing the patient to labor in the future, should she desire. Signed written, informed consent was obtained by the patient authorizing publication. Figure 4 High-resolution image of the accessory and cavitated uterine mass cavity with surgical marking pen for size. High-resolution image of the accessory and cavitated uterine mass cavity with surgical marking pen for size.

Hope Knochenhauer: Writing – review & editing, Writing – original draft. Lili Mohebbi: Writing – original draft. Eric Knochenhauer: Writing – review & editing, Conceptualization.

In a review of the literature, minimal recommendations were found for conservative and medication management of ACUM. On the basis of this case report, for patients with severe pain secondary to ACUM, norethindrone acetate suppression may be a viable option. Because the patient was asymptomatic with norethindrone acetate (5 mg orally once a day), there was no need to titrate the dose higher. However, if patients continue to have pain with the starting regimen, it is reasonable to titrate the dose up to the maximum dose of norethindrone acetate (15 mg orally once daily). Because our patient was not sexually active throughout her treatment period, contraceptive benefits did not need to be considered. For patients who additionally desire contraception, combination OCPs given continuously can also be considered for conservative management. Due to leuprolide acetate’s side effect profile, it is not considered first-line treatment. Additionally, its safety has not yet been studied in patients aged <18 years, similar to our patient was when she initiated medical therapy. Although the intention for this patient was to delay surgery, for patients who are poor surgical candidates or do not desire surgical management, norethindrone acetate may be a viable, long-term option.

Accessory and cavitated uterine mass (ACUM) is defined by an accessory cavity lined by functional endometrium in an otherwise normal uterine cavity ( 1 , 2 ). Accessory and cavitated uterine masses are usually located in the lateral aspect of the myometrium near where the round ligament inserts ( 3 , 4 ). The endometrial cavity itself is usually unaffected and communicates normally with the fallopian tubes ( 3 ). Accessory and cavitated uterine mass, although rare, often presents with severe dysmenorrhea and chronic pelvic pain that significantly impact affected individuals and can be indistinguishable from other conditions such as endometriosis ( 2 , 4 , 5 , 6 ), rudimentary horn ( 3 , 4 ), degenerating fibroids ( 3 , 4 ), and cystic areas within adenomyosis ( 3 ). These factors make it a unique challenge in gynecological diagnostics and management. Symptoms of ACUM typically manifest in adolescents and nulliparous individuals, with an average symptom duration of around 24 months before diagnosis ( 7 , 8 ). Although there is currently no studied association of ACUM with infertility, a few case reports report coexistent infertility ( 4 ). Imaging techniques such as pelvic ultrasound and magnetic resonance imaging (MRI) are instrumental in establishing an early diagnosis. In patients with ACUM, pelvic ultrasound commonly shows a well-defined mass within the myometrium, surrounded by a vascular ring and featuring a heterogeneous center. Magnetic resonance imaging provides further detail, identifying the lesion as intramyometrial and clearly distinct from the endometrial cavity, with a heterogeneous hyperintense core ( 4 , 9 , 10 , 11 ). Expertise and standardization in radiologic diagnostic criteria for ACUM using these modalities remain an area requiring further development. Initial medical treatment, usually before diagnosis of ACUM, includes use of nonsteroidal anti-inflammatory drugs and hormonal treatments such as oral contraceptive pills (OCPs); however, their effectiveness is usually variable ( 8 ). A systematic review of ACUM literature found that only 16.7% of patients proceeded with conservative, nonsurgical management, such as sclerotherapy and medication management, after the diagnosis of ACUM was made ( 8 ). Of those patients who pursued conservative management, 21% eventually required surgical intervention ( 8 ). Another review found that 90.7% of patients had complete resolution of pain and symptoms with surgical management ( 4 ). In a Letter to the Editor titled “Accessory and cavitated uterine mass versus juvenile cystic adenomyoma,” the investigators state that ACUMs require surgical excision ( 3 ). Strug et al. ( 4 ) similarly argue that medical management of ACUM is unnecessary because it only delays definitive treatment of surgery and reduces fertility via prolonged hormonal suppression. Although surgical resection of the accessory mass remains the definitive treatment, lack of standardized trials due to the low incidence of ACUM and delayed diagnosis hinders the opportunity for long-term nonsurgical management of ACUM ( 7 , 8 ). Our case report describes a unique case where conservative management of ACUM using norethindrone acetate successfully suppressed symptoms for an extended period of time. Norethindrone acetate was chosen for its menstrual suppression abilities and minimal side effect profile ( 12 ). Seventy-six percent of patients taking norethindrone acetate (5 mg orally once a day) achieve amenorrhea ( 12 ). If this dose does not achieve amenorrhea, it can be titrated up to the maximum dose of norethindrone acetate (15 mg orally once a day). Although estrogen-containing OCPs achieve similar rates of amenorrhea when used continuously (49%, 68%, and 88% at cycles 2, 6, and 12, respectively), estrogen-containing products have an increased risk of breakthrough bleeding ( 12 ). Because even breakthrough bleeding has the potential to cause pain for patients with ACUM, norethindrone acetate is theoretically more likely to help achieve complete symptomatic control. One drawback of norethindrone acetate is that is it not Food and Drug Administration approved for contraception use ( 12 , 13 ). Gonadotropin-releasing hormone agents, such as leuprolide acetate, can also be used for amenorrhea ( 12 ). These agents achieve high rates of amenorrhea with 98% of patients experiencing amenorrhea after their second 3-month injection ( 14 ). Despite this high rate of amenorrhea, they are not the preferred first-line agent for patients because the side effects of menopausal symptoms can be limiting and there is a negative effect on bone density with prolonged use ( 12 , 14 ). Its safety has not been studied in patients aged <18 years ( 14 ). Additionally, the initial stimulatory effect may cause increased pain in patients with an ACUM ( 14 ). The aim of this report is to delineate the clinical features, diagnostic approaches, and management strategies for ACUM, highlighting current gaps in knowledge and exploring potential improvements in nonsurgical treatment protocols.

H.K. has nothing to disclose. L.M. has nothing to disclose. E.K. has nothing to disclose.