Uterine Incarceration Caused by Adenomyosis: A Case Report With Review of Relevant Literature

A 49 year old multiparous woman was admitted to the emergency department due to a 1 week history of lower abdominal pain and difficulty urinating. The patient denied any prior history of urinary tract infections or urinary retention. One week prior to admission, she began experiencing dysuria with a urinary frequency of 8–10 episodes daily, accompanied by a sensation of incomplete bladder emptying. Three days before presentation, she developed progressively worsening lower abdominal distension and pain. Upon admission, she reported an inability to void for nearly 10 h, with severe suprapubic discomfort. The patient was transferred from the emergency department to the gynecology ward. Upon admission, her vital signs remained within normal limits. Abdominal examination revealed a soft and relaxed abdomen with mild suprapubic tenderness. On vaginal examination, an enlarged retroverted uterus (approximately 16‐week size) was noted, with anterior displacement of the cervix. A palpable mass was detected in the posterior fornix. The indwelling urinary catheter remained in place. Attempts at manual repositioning through vaginal manipulation failed to mobilize the incarcerated uterus. Serum β‐human chorionic gonadotropin (β‐hCG) testing returned negative results, effectively excluding pregnancy as a contributing factor to her symptoms. Laboratory tests showed anemia (hemoglobin: 80 g/L) and elevated CA‐125 (150.30 U/mL). All laboratory parameters including liver function, renal function, coagulation, electrolytes, and urinalysis were within normal limits. Ultrasound demonstrated an enlarged, heterogeneous uterus, bilateral adnexal cystic lesions (O‐RADS 2–3), and significant post‐void residual urine (531 mL) (Figure  1A ). Pelvic MRI demonstrated a markedly enlarged uterus (9.0 × 11.0 × 9.0 cm) with characteristic features of adenomyosis. The uterine body was incarcerated posterior to the cervix, forming a 180‐degree retroflexion (Figure  1B ). Pelvic imaging findings. (A) Transvaginal ultrasound reveals an anteverted uterus with marked post‐void residual urine in the bladder. (B) Abdominal magnetic resonance imaging (MRI) shows a retroverted uterus, adenomyosis, and diffuse thickening of the uterine walls. BL, bladder; CX, cervix; UT, uterine body.

Ziwen Lei: conceptualization, formal analysis, methodology. Jie Liu: conceptualization, data curation, formal analysis, investigation, methodology, writing – original draft, writing – review and editing. Na Sang: data curation, investigation. Qi Tian: investigation, methodology, resources, validation, writing – review and editing. Chuqiang Shu: investigation, methodology, resources, validation, writing – review and editing. Guang Li: project administration, resources, validation, visualization, writing – review and editing.

This work was supported by Hunan Provincial Department of Education Scientific Research Project (24C0185). Changsha Natural Science Foundation (kq2502014). Hunan Provincial Health Commission Research Project (20254316). Ruixin project of Hunan Provincial Maternal and Child Health Care Hospital (2023RX31). National Natural Science Foundation of China (82503240).

Postoperatively, the patient's symptoms resolved completely, with normal bladder function restored by postoperative Day 2. She was discharged on Day 5 without complications. Follow‐up at 6 weeks confirmed complete resolution of symptoms and no evidence of residual urinary dysfunction.

This case illustrates an exceptionally rare complication of adenomyosis, where marked uterine enlargement precipitates pelvic incarceration culminating in complete urinary obstruction. The pathophysiological cascade involves both direct mechanical compression of the bladder neck/urethral outlet and predisposing anatomical factors—in this case, diffuse adenomyosis led to uterine enlargement and retroversion, while pelvic adhesions (possibly secondary to chronic inflammation or prior subclinical events) may have contributed to fixation [ 3 ]. However, the primary driver appeared to be adenomyosis. These pathological changes manifest clinically through characteristic compression symptoms: positional lower abdominal pain, progressive dysuria evolving to acute retention, and associated bowel dysfunction (constipation/tenesmus) [ 4 ]. Such acute urinary retention constitutes a urological emergency, necessitating immediate intervention to avert severe sequelae including detrusor dysfunction, ascending UTI, obstructive uropathy, and in extreme cases, bladder rupture [ 5 ]. Diagnosis relies on thorough physical examination and imaging. Although ultrasound is the initial screening tool, MRI is superior for delineating uterine‐cervical anatomy and assessing surrounding structures [ 6 ]. Key MRI findings include: (1) retroverted uterus fixed in the sacral hollow, (2) elongated and elevated cervix, and (3) bladder compression with distension [ 7 ]. Early imaging is crucial to prevent irreversible bladder damage. Management should be individualized. Conservative approaches (e.g., postural reduction, vaginal manual reduction, cervical traction) may be attempted initially [ 8 ]. Refractory cases may require minimally invasive techniques (e.g., laparoscopic ligamentopexy or colonoscopic‐assisted decompression) [ 9 , 10 ]. Short‐term intrauterine device placement has been proposed to prevent recurrence, though evidence remains limited [ 11 ]. For patients without fertility desires, hysterectomy is a definitive solution [ 6 ]. Urinary retention mandates prompt catheterization and decompression to avert renal complications [ 12 ]. We acknowledge that the causal role of adenomyosis in incarceration is based on a single observational case. Larger studies are needed to validate this association and refine treatment protocols. In conclusion, this case demonstrates that adenomyosis, though rare, can cause uterine incarceration in non‐gravid women. MRI is the diagnostic gold standard, and hysterectomy is an effective treatment for patients not seeking fertility preservation. Clinicians should consider uterine incarceration in cases of unexplained urinary retention, particularly with concurrent uterine enlargement. Further research is needed to elucidate the relationship between adenomyosis and incarceration and to refine treatment protocols.

Written consent for the publication of this case report was obtained from the patient.

Uterine incarceration is an uncommon complication that occurs when the uterus becomes trapped between the sacral promontory and the pubic symphysis [ 1 ]. Although predominantly recognized as an obstetric complication with an estimated incidence of 1 in 3000 pregnancies, it is exceedingly rare in non‐pregnant women, with only sporadic cases reported in the literature. Adenomyosis represents a potential contributing factor for uterine incarceration, particularly when affecting the posterior uterine wall. The clinical manifestations often overlap with those of adenomyosis, including abnormal uterine bleeding and pelvic pain [ 2 ]. However, uterine incarceration secondary to adenomyosis presenting primarily with urinary retention is exceptionally uncommon. Here, we report a rare case of uterine incarceration causing acute urinary retention in a non‐gravid patient and discuss its management strategies.

The authors declare no conflicts of interest.

Urinary retention was immediately managed with catheterization (350 mL drained). Due to the inability to perform hysteroscopy (cervix inaccessible), further diagnostic procedures were deferred. The bilateral adnexal cystic lesions were considered benign based on imaging and did not influence the surgical plan, as the primary indication for hysterectomy was symptomatic uterine incarceration. Given the patient's lack of fertility desire and concerns regarding symptom recurrence, she underwent an open abdominal hysterectomy. Intraoperative findings revealed a fixed uterus within the pelvic cavity, densely adherent to the bowel and pelvic sidewalls, retroverted and incarcerated in the cul‐de‐sac. Prior to hysterectomy, the surgical team first performed adhesiolysis to release pelvic adhesions. Manual anterosuperior traction was then applied to the uterine fundus to successfully dislodge the incarcerated uterus from the cul‐de‐sac. Histopathological examination confirmed the diagnosis of adenomyosis (Figure  2 ). Histopathological appearances of the uterine specimen at different magnifications. Typical pathological features of adenomyosis are observed under 40×, 100×, and 400× microscopic magnification, respectively.