Bladder endometriosis mimicking bladder neoplasm: A case report

Abstract

Endometriosis has traditionally been considered a gynecological condition. However, it is increasingly recognized as a multiorgan and systemic inflammatory disease that requires interdisciplinary care, spearheaded by a gynecologist with specialized training in clinical and surgical management. Bladder endometriosis is an extremely uncommon but dangerous type of infiltrating endometriosis, for which only pathological examination can establish a diagnosis. This case report describes a rare presentation of endometriosis mimicking a bladder neoplasm in a 44-year-old woman, emphasizing the importance of a thorough evaluation.

Introduction

Endometriosis is characterized by the presence of endometrial-like epithelium and/or stroma outside the endometrium and myometrium, typically accompanied by inflammation. The etiology of endometriosis remains largely unknown. It is most likely a hereditary chronic disorder with an unknown mode of inheritance [1,2]. Endometriosis is a chronic and benign disease that affects up to 10% of women. Bladder endometriosis is a type of endometriosis that occurs due to the presence of endometrial tissue and stroma in the detrusor muscle. This disease can affect different parts of the bladder, especially the base and dome, with varying degrees of penetration [3]. Historically, it has been considered as a gynecological condition and was treated by obstetricians and gynecologists. Recently, endometriosis has been considered a multiorgan inflammatory disease that requires coordinated management [4,5]. It is believed to cause pelvic pain and infertility. Other symptoms include pelvic pain, bloating, changes in bowel movements, urinary problems, and fatigue. Urinary tract endometriosis is a rare but uncommon condition yet severe variant of infiltrating endometriosis, with the potential for urinary tract blockage and renal function impairment. The diagnosis of urinary tract endometriosis has become increasingly prevalent, accounting for approximately 7% of all endometriosis cases [3]. Endometriosis rarely involves the uterus extra peritoneally; however, it can involve the chest [6] or skin around implants from previous gynecological procedures [7]. Imaging techniques currently used to diagnose pelvic endometriosis include ultrasonography and magnetic resonance imaging (MRI). This study presents a case of suspected bladder neoplasm in a patient with bladder endometriosis.

Case presentation

A 44-year-old married woman presented with a 2-day history of gross hematuria and lower abdominal pain. The patient was otherwise healthy and had no significant family or medical history. Physical examination was unremarkable. A complete blood count, urinalysis, and renal function tests were performed to exclude urinary tract infection. The complete blood count result showed a decrease in the levels of hemoglobin (HB), hematocrit (HCT), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) with normal erythrocytes and white blood cells (HB: 10.3 g/dl, HCT: 31.2%, MCV: 73.6 fL, MCH: 24 pg, erythrocytes: 4.3 × 10¹²/L, white blood cells: 10 × 10⁹/L). Urinalysis was negative except for red blood cells (urine albumin: negative, red blood cells: 6-8/HPF, white blood cells: 1-2/HPF). The results of the renal function test were normal (blood urea nitrogen: 9 mg/dl, creatinine 0.6 mg/dl). An ultrasound was performed to assess the condition of the kidneys and urinary bladder to check for stones in the urinary tract. The scan revealed focal mural thickening of the posterior wall of the urinary bladder. Further investigation using computed tomography urography (CTU) revealed a filling defect and focal thickening in the left posterolateral wall of the urinary bladder (Fig. 1A and B), indicative of a potential bladder neoplasm. Pelvic MRI with IV contrast was performed and confirmed the presence of the mass with multiple T1 hyperintense areas within it and heterogeneous enhancement (Fig. 1C and D). A bladder neoplasm with hemorrhagic foci and bladder endometriosis were the top differential diagnoses. After an MDP meeting, a decision was made to perform transurethral resection of the bladder tumor (TURT). The final diagnosis of bladder endometriosis was made after surgical excision and histopathological examination. The histopathological results showed the tumor lining up with benign urothelium, with some of the epithelial layers replaced by bland-looking glandular epithelium lining up with ciliated cells that went into the lamina propria. Intervening stroma showed scattered hemosiderin-laden macrophages (Fig. 2). The findings were compatible with mullerinosis (endosalpingiosis and endometriosis). These findings emphasize the importance of excisional biopsy in cases with ambiguous imaging findings, crucial to achieve a definitive diagnosis.

Fig. 1.

(A and B) CT Urography delayed phase images (A) axial cut (B) and sagittal cut. They shows filling defect and mural thickening in the left posterolateral wall of the urinary bladder (Black arrow). (C and D) MRI pelvis (C) T1fat saturation image axial cut (D) post contrast image. They shows areas of T1 high signal intensities (white arrow) (C) which shows heterogeneous enhancement on post contrast images (white arrow) (D).

Fig. 2.

Endometriosis histopathology shows Transitional urothelium with foci of endometrial glands (glandular epithelium lining up with ciliated cells) (black arrows) (A) H&E stain. (B) Positive estrogen receptors.

Discussion

Endometriosis is a complex medical condition that continues to challenge medical practitioners. Urinary tract endometriosis has been reported to affect up to 1% of women with pelvic endometriosis, particularly bladder endometriosis, with a frequency of 20%-50% in women with deep endometriosis [8]. The prevalence of urinary tract endometriosis in the general female population is ambiguous, with approximately 50% of women with urinary tract endometriosis being asymptomatic [8]. As in the present case, urinary tract endometriosis predominantly affects the bladder [9]. The precise pathophysiological mechanism of this condition remains controversial; nonetheless, 3 predominant theories exist about the etiology of bladder endometriosis:

• •It originates from Müllerian remnants in the vesicouterine/vesicovaginal septum.
• •It is, in fact, an expansion of an adenomyotic nodule of the anterior uterine wall.
• •It arises from the implantation of regurgitated endometrium [10].

Individuals with bladder endometriosis typically exhibit vague symptoms. Approximately 50% of women with ureteral obstruction are asymptomatic, 25% exhibit flank pain, and 15% experience significant hematuria, as observed in the present case [[11], [12], [13]]. Additional concurrent symptoms linked to urinary tract endometriosis include dysmenorrhea and profound dyspareunia [8].

Transabdominal and transvaginal ultrasounds are the preferred initial modality for assessing suspected bladder endometriosis due to their immediate availability and accessibility [14]. Ultrasound can reveal localized thickening of the bladder wall, contributing to the differential diagnosis of bladder endometriosis, subserosal anterior leiomyoma, and bladder cancer, as in the present case. However, MRI not only clearly shows the morphological issues of bladder endometriosis but may also show other more common locations, especially at the uterosacral ligament, where ultrasonography is not as reliable. Common MRI characteristics include localized or diffuse thickening of the bladder wall, particularly affecting the dome or posterior wall, heterogeneous T2 isointensity, and sporadic T1 hyperintense foci [15], as observed in the present case.

Cystoscopy, along with ultrasonography or MRI, is an essential procedure for accurately identifying the lesion and assessing its depth and proximity to the ureters. Bladder endometriosis can present in many ways, from a raised mucosa that appears normal because of a submucosal nodule to full invasion through the mucosa. Additionally, it can aid in the exclusion of cancers [16]. The proximity of the lesion to the ureteral orifices may also facilitate surgical planning.

Tissue biopsy and histological confirmation represent the definitive standards for diagnosing upper extremity conditions [8].

Excluding compromised renal function is crucial when upper extremity issues are suspected. Renal function tests and urinalysis, including assessments for infection, should be performed in patients presenting with flank pain or hemorrhage [17].

The aim of treating bladder endometriosis is to alleviate symptoms and prevent potential kidney impairment. The selection of treatment is contingent upon various parameters, including the size of the nodule, quantity, location, symptoms, and presence or absence of hydronephrosis. Potential strategies encompass expectant care, pharmacological intervention, and surgical procedures. Asymptomatic women without hydronephrosis may choose a conservative strategy with regular ultrasound examinations. Nevertheless, surgical intervention is essential for patients with ureteral blockage and hydronephrosis. Medical interventions or surgical procedures may address illness-related pain [15]. Medical treatment involves progesterone, combined estrogen-progesterone therapy, and GnRH analogs [17].

Treatment involves surgical resection, performed via laparotomy or laparoscopy. The recurrence rates range from 16% to 25% at 36 months [18]. In a previous study, Chen indicated that a partial cystectomy is the preferable approach for full-thickness bladder lesions due to its efficacy [19]. However, the clinical management in the present case was different; the mass was removed transuretherally because of suspicion of a bladder neoplasm.

Conclusion

Bladder endometriosis is a rare condition with no specific clinical or radiological findings, and its diagnosis can only be established via histopathology. For these reasons, female patients of reproductive age with complaints of urinary symptoms and a bladder mass should be investigated for bladder endometriosis in collaboration with urologists and gynecologists.

Patient consent

Informed, written consent was obtained from the patient for publication of his son case.