Successful Robotic Enucleation of a Rare Bladder Leiomyoma Through a Trans-Vesical Route: A Novel Surgical Approach

Abstract

Background: Bladder leiomyomas are rare benign tumors (<0.5% of all bladder tumors) arising from the bladder wall’s smooth muscle. Only 250 cases of this condition have been reported worldwide so far. While some leiomyomas present with irritative or obstructive symptoms, hematuria, or nonspecific abdominal pain, others are asymptomatic and are diagnosed incidentally. The surgical approach is based on the leiomyoma’s size and location. Given this tumor’s rarity, standardized management guidelines do not exist; however, transurethral resection of bladder tumor (TURBT), partial or radical cystectomy, or laparoscopic/robotic enucleation are viable therapeutic options. Case history: We report the case of a 64-year-old female presenting with recurrent colic and pelvic pain. An abdominal CT scan showed a 3 cm mass protruding from the posterior bladder wall toward the right vaginal fornix. A transvaginal ultrasound-guided through-cut biopsy confirmed the diagnosis of a bladder leiomyoma. Due to the tumor’s size and location, robotic enucleation was chosen to minimize the risk of bladder perforation. The mass was successfully excised via a transvesical approach. Results: The procedure was completed in 210 min without complications, with 50 mL blood loss. The patient recovered well, with resolution of symptoms and no recurrence at eighteen-month follow-up. Histopathological examination on the surgical specimen confirmed the diagnosis of bladder leiomyoma. Conclusions: This case highlights the feasibility and safety of robotic enucleation for large bladder leiomyomas, emphasizing minimal invasiveness, limited pelvic dissection, and preservation of bladder function. Further research and standardized guidelines are needed for managing this rare condition.

1. Introduction

Leiomyoma is a benign tumor originating from the smooth muscle tissue. These tumors can develop wherever smooth muscle is present, with the most common locations being the uterus (where they are known as fibroids) and the gastrointestinal tract. Bladder leiomyomas are particularly rare, accounting for approximately 0.43% of all bladder tumors [1]. Around 250 cases have been documented so far, including cases involving the urethra. Often, bladder leiomyomas are detected incidentally, as they can present a wide range of nonspecific symptoms, such as lower urinary tract obstruction, irritative urinary symptoms, hematuria, and dysuria [2,3,4].

Surgical removal represents the primary treatment option for leiomyomas, with the approach tailored to the tumor’s size and location. Smaller, accessible bladder tumors can be removed via transurethral resection, while tumors in less accessible areas may require segmental resection or partial cystectomy [5,6].

2. Case Presentation

Our patient was a 64-year-old lady with a medical history significant only for autoimmune hypothyroidism under replacement therapy. She presented to our clinic with general symptoms of colic and pelvic pain, which were poorly controlled with NSAIDs and ranged from 2 to 7 on the VAS scale. An abdominal contrast-enhanced computed tomography (CT) scan revealed a 3 cm mass protruding from the posterior right bladder wall and extending towards the right vaginal fornix (Figure 1A,B). Cystoscopic examination showed a submucosal protrusion in the right lateral wall, approximately 2 cm proximal to the right ureteral orifice. Due to the postero-lateral position and the extravescical protrusion, the patient underwent an ultrasound-guided transvaginal thought-cut biopsy, which allowed the definitive diagnosis of bladder leiomyoma, with overlying benign bladder mucosa.

Given the tumor’s position and size, we deemed an endoscopic resection a high-risk option, due to the potential for bladder perforation and incomplete resection. After discussing the options with the patient, a robotic enucleation was selected as the most suitable approach to reduce invasiveness, allow for better suturing and visualize the right ureteral orifice more closely during the excision. Moreover, a transvesical approach, similar to the one used for repair of a vesico-vaginal fistula in our experience, was preferred, in order to reduce the lateral dissection of the bladder and the vagina and prevent devascularization and denervation at those sites [7].

The patient was positioned supine, and a standard robotic cystectomy port configuration was used (Figure 2). A 7 cm anterior median bladder cystotomy was made, suspended by bilateral stitches to optimize visualization and access to the internal surface of the bladder (Figure 3A). To safeguard the right ureter, a 6 Ch mono-J ureteral stent was placed on a guide passed through the bladder catheter. With the bladder opened, the leiomyoma was identified within the submucosal layer of the right posterior-inferior wall, and excised proceeding from the inside to the outside (Figure 3B,C). Notably, care was taken to preserve the integrity of the right ureteral orifice. The 3 cm mass was placed in an endobag and eventually removed through the camera port-site (Figure 3D). The cystotomy at the right lateral side was closed with a 2-0 V-loc running suture on the muscular layer and with a 4-0 Monocryl suture for the mucosa, as was the anterior median cystotomy. A 20 Ch open-tip Foley catheter was placed transurethrally and secured externally to the ureteral mono-J stent. A para-vesical laminar drain was inserted via a lateral trocar for postoperative drainage.

The procedure was completed successfully in 210 min, with minimal intraoperative blood loss (50 mL) and no intraoperative complications. The mono-J stent was removed after 24 h. The patient was discharged on the third post-operative day with the bladder catheter, which was removed 2 weeks later in an outpatient setting. Histopathological examination confirmed a rare form of leiomyoma of the bladder, with no signs of malignancy (Figure 4A,B). At an eighteen-month follow-up, the patient reported complete resolution of her preoperative symptoms and no other modification of her nycturia habits or lifestyle.

3. Discussion

Bladder leiomyoma is a rare, benign mesenchymal tumor, constituting less than 0.5% of all bladder tumors. It was first described by Kretschmer et al. in 1931. Between 2012 and 2017, He et al. documented 21 cases across 20 reports in the English literature, finding that the incidence is twice as high in women as in men. Additionally, middle-aged patients around age 50 tend to experience the most significant symptoms [8].

The exact cause of bladder leiomyomas remains unclear, though several theories offer potential explanations. Blum’s irritative theory suggests chronic inflammatory stimuli on the bladder wall and detrusor muscle could be the cause. Other hypotheses propose that leiomyomas may arise from perivascular inflammation or chromosomal alterations. Piegel’s disontogenic theory links these tumors to embryonic remnants from Mullerian and Wolffian ducts, while Lipschutz’s theory suggests an endocrine basis, implicating the effects of estrogen and progesterone. This hormonal theory is supported by the higher prevalence among fertile women and the presence of ovarian steroid receptors on some tumors [9].

Bladder leiomyomas are classified by location as endovesical (63–86% of cases), intramural (3–7%), or extravesical (11–30%). Patients may be asymptomatic; however, most experience symptoms based on tumor size and location, such as obstructive symptoms (49%), irritative symptoms (38%), or hematuria (11%) [9]. Larger or strategically positioned tumors, particularly in the bladder trigone, are more likely to cause severe obstruction.

Diagnosis of bladder leiomyomas typically involves ultrasound, CT, MRI, and cystoscopy. Ultrasound often reveals smooth, homogeneous lesions with peripheral hyperechogenicity. CT is useful for determining tumor size and bladder displacement, and MRI offers superior detail in delineating tumor boundaries. On MRI, leiomyomas appear as medium signal on T1-weighted imaging and homogeneous low-signal on T2-weighted imaging, resembling uterine leiomyomas. Post-gadolinium contrast may show variable enhancement, with degenerated areas showing no enhancement [3,8]. However, only histopathological analysis can confirm the diagnosis of a benign tumor, as imaging alone cannot rule out malignancy.

Histologically, leiomyomas are well-demarcated, encapsulated masses with yellow-tan cut surfaces. Microscopically, they consist of smooth muscle fascicles arranged around vascular structures with no signs of mitotic activity, hemorrhage, or necrosis. Immunohistochemistry shows positive staining for markers such as smooth muscle actin (SMA), muscle-specific actin (MSA), desmin, h-caldesmon, and vimentin, while negative for keratins and epithelial membrane antigen (EMA). Invasion of the detrusor muscle is critical for distinguishing leiomyomas from leiomyosarcomas [10], with only one reported case of malignant transformation [11].

The choice of treatment (

Table 1. Comparison of the most common surgical approaches for the treatment of bladder leiomyomas.

Surgery Method	Suitable Condition	Costs	Expected Outcome	Recovery Time
TURB	Small, endovescical mass	Low	Bladder preservation, possible recurrence	Short
Transvaginal resection	Extravescical mass adjacent to vagina	Low	Bladder preservation, low recurrence rate	Medium
Partial cystectomy	Large mass, extravesical growth or unfavorable position	Low–Medium	Reduction on bladder capacity, low recurrence rate	Medium
Minimally Invasive Enucleation	Endovescical, intramural, extravescical	Medium–High	Bladder preservation, low recurrence rate	Short

) depends on tumor size, location, and relation to the bladder wall, with surgery generally recommended to prevent potential tumor growth [9]. Conservative surgery is preferred, with options ranging from transurethral resection to open excision. Transurethral resection is typically recommended for smaller tumors. Other minimally invasive approaches, such as laparoscopic cystotomy or robotic extramucosal excision, are suitable for certain cases [9,12]. In rare instances, transvaginal resection has been performed for accessible tumors [13]. In our case, the patient’s symptoms and tumor location made robotic resection an effective approach, yielding a successful outcome despite the tumor’s large size.

Recurrence after surgery is rare, with recurrent tumors managed successfully through repeat transurethral resection or enucleation [8]. No formal guidelines exist currently for follow-up; however, routine invasive monitoring is generally not recommended for treated asymptomatic patients, avoiding unnecessary exposure to invasive or radiologic tests.

Conclusive Remarks

Bladder leiomyomas are rare tumors, and can cause a range of clinical problems, including pain, hematuria, and obstructive lower urinary tract symptoms. Data on mini-invasive surgical excision of bladder leiomyomas are scarce. We present a case of a large bladder trigone leiomyoma, treated successfully using a robotic trans-vesical approach, with curative intent. Follow-up demonstrated successful outcome and no residual symptoms, relapse, scarring, distortion of the bladder trigone, or ureteral orifice damage, underscoring the potential of thorough tumor removal with the mini-invasive approach, while preserving bladder and pelvic function. Case reports on rare urological diseases are crucial to share experiences on cases where limited data are present, and no shared guidelines can be applied. The European Reference Network eUROGEN is currently working on facilitating data exchange between different European centers and developing guidelines on rare diseases in Urology [14]. It is the authors’ intention to contribute to the Network work by reporting this experience on a rare urological case with successful outcome using a novel surgical approach.