Recurrent giant multilocular prostatic cystadenoma: A case report after a decade in Vietnam

Abstract

Giant multilocular prostatic cystadenoma is a rare benign tumor with high recurrence rates and aggressive local growth. We report a 41-year-old man with nearly a decade of recurrent disease presenting with worsening urinary symptoms, pelvic pain, and defecatory difficulties. Despite multiple procedures including transurethral resection and robotic cyst excision with benign histopathology, recurrence persisted. In 2025, MRI revealed a massive multiloculated cystic mass (106 × 109 × 174 mm) compressing the rectum and prostate with elevated PSA (38 ng/mL). Given recurrent disease and severe pelvic compression, he underwent radical prostatectomy with en bloc cyst excision. Three-month follow-up showed no recurrence and complete symptom resolution.

Highlights

• •Giant multilocular prostatic cystadenoma is a rare benign tumor in the prostate that can be misdiagnosed as malignant.
• •It may have long recurrence periods, so patients need annual follow-ups.
• •In some cases, radical prostatectomy may be necessary to prevent recurrence.

1. Introduction

Cystic lesions of the prostate, while uncommon, represent a diverse group of conditions ranging from congenital to inflammatory and neoplastic origins. The majority of prostatic cysts are small and asymptomatic, often discovered incidentally. However, giant multilocular prostatic cystadenoma (GMPC) stands out as one of the rarest benign tumors of the prostate, with fewer than 30 documented cases worldwide.¹ GMPC is featured by sizable multiloculated cystic masses that are lined by benign prostatic epithelium. Despite its histologically benign nature — characterized by bland prostatic glandular epithelium without cytologic atypia or invasive features — GMPC can grow to considerable size, producing significant mechanical displacement of adjacent pelvic structures. Recurrence, while well-documented in the literature, appears to be driven primarily by incomplete surgical excision rather than intrinsic tumor aggressiveness, occurring in only 1 of 15 patients (6.7%) with long-term follow-up in the largest published case compilation.¹ Its rarity often results in misdiagnosis as malignancy or confusion with cystic diseases of nearby pelvic organs, such as the seminal vesicles or bladder. With no established consensus on the best surgical management strategy, especially for recurrent cases, our case report seeks to provide valuable insights from our experience in managing recurrent giant multilocular prostatic cystadenoma, highlighting the need for increased awareness and effective treatment approaches in this challenging area.

2. Case presentation

A 41-year-old man presented with escalating lower urinary tract symptoms, chronic discomfort in the suprapubic area, and persistent challenges with defecation that had progressively worsened over several months. Ten years ago, in 2016, pelvic multi-slice computed tomography (MSCT) identified a cystic mass posterior to the bladder, initially suspected to originate from the right seminal vesicle, potentially causing ejaculatory duct obstruction (Fig. 1). He underwent transurethral endoscopic cyst resection, and the histopathological analysis confirmed the presence of a benign cystic lesion. Two years later, the patient returned to our department, where a MSCT showed considerable prostate enlargement (82 × 78 × 96 mm), almost entirely occupied by multiloculated cystic structures that were compressing the bladder neck (Fig. 2). Following this, he underwent a robotic excision of the cystic mass, and final pathology established the diagnosis of giant multilocular prostatic cystadenoma. In 2025, the patient returned again, now facing worsening urinary symptoms and significant pelvic pressure, along with chronic defecatory difficulties. Notably, his serum PSA was strikingly elevated at 38 ng/mL. A contrast-enhanced pelvic MRI revealed a massive multiloculated cystic mass, approximately 106 × 109 × 174 mm in size, situated in the pelvic retroperitoneal space anterior to the sacrum. This mass caused significant anterior displacement and compression of the rectum, correlating directly with the worsening defecation issues (Fig. 3). Given the clinical history, imaging findings, and prior pathological results, the diagnosis of recurrent giant multilocular prostatic cystadenoma was confirmed. To mitigate the risk of further recurrence, a plan was established for open radical prostatectomy with en bloc excision of the cystic mass. After the successful excision of the prostate and cystic lesion, a tension-free vesicourethral anastomosis was crafted over a 14-Fr silicone Foley catheter. An 18-Fr suprapubic cystostomy catheter was placed for urinary diversion. The postoperative period was remarkably smooth, with no significant complications. Initially, urinary drainage was facilitated through both urethral and suprapubic catheters. On postoperative day 10, a voiding cystourethrography was conducted, which revealed no signs of urinary leakage or fistula. After confirming an intact vesicourethral anastomosis, both the urethral and suprapubic catheters were removed. Following catheter removal, the patient was able to void spontaneously without any difficulty. Remarkably, his defecatory symptoms improved significantly, demonstrating a complete resolution of pelvic pressure and enhanced bowel movements due to the decompression of the rectum. Histopathological examination confirmed the diagnosis of GMPC. Grossly, the specimen comprised a prostate gland measuring 4 × 3 × 3 cm with an associated posterior cystic lesion measuring 13 × 7 × 6 cm. On serial sectioning, the lesion demonstrated a yellowish-brown cut surface with cystic change, containing multiple internal septations filled with greenish-yellow fluid; serial sectioning of the prostate gland itself revealed no lesion. Microscopically, the tumor was well-circumscribed and encapsulated, composed of multiloculated cystic spaces lined by cuboidal to low-columnar epithelial cells with small, round, centrally located nuclei, supported by fibrous stroma. Cytologic atypia, mitotic figures, and stromal invasion were absent. Immunohistochemical staining confirmed expression of PSA, p63, and CK5/6, supporting prostatic glandular differentiation and the integrity of the basal cell compartment (Fig. 4). At the three-month follow-up, no early signs of recurrence were detected, and the patient remained asymptomatic and in excellent health to date.

Fig. 1.

In 2016, MSCT showing a cystic mass posterior to the bladder, initially suspected to originate from the right seminal vesicle, potentially causing ejaculatory duct obstruction (white arrow) arising from the prostate gland and measuring about 80.5 mm × 74.5 mm in size.

Fig. 2.

In 2018, MSCT, (A) axial and (B) coronal views, showing a large multiloculated mass with heterogeneous density (yellow arrow) arising from the prostate gland and measuring about 80.4 mm × 67.7 mm × 74.1 mm in size, almost entirely occupied by multiloculated cystic structures that were compressing the bladder neck.

Fig. 3.

In 2025, T2-weighted magnetic resonance imaging showing a recurrent cystic multiseptated mass displacing the surrounding structures, (A) axial and (B) sagittal views.

Fig. 4.

Microscopic findings of the resected specimen. (A): Variously sized multiloculated cystic spaces lined by benign prostatic-type epithelium, on low-power magnification (hematoxylin and eosin, original magnification 10 × ). (B): Cystic spaces lined by cuboidal to low-columnar epithelial cells with small, round, centrally located nuclei and a distinct, intact basal cell layer; cytologic atypia, mitotic figures, and stromal invasion are absent (40 × ). (C): Immunohistochemical staining showing positive expression of prostate-specific antigen (PSA), p63, and CK5/6 in the cystic epithelium, confirming prostatic glandular differentiation and basal cell layer integrity (20 × ).

3. Discussion

A giant multilocular prostatic cystadenoma is an extremely rare benign tumor that originates in the prostate glands. Since Maluf et al. reported the first case in 1991, fewer than 30 cases have been documented 1, 2, 3. This rarity, combined with its nonspecific presentation, often leads to misdiagnosis as cystic disease arising from adjacent pelvic organs or as a malignant tumor of the prostate or seminal vesicles.

On imaging studies, a giant multilocular prostatic cystadenoma typically appears as a large, well-defined, multiloculated cystic mass with thin septations on computed tomography (CT) and magnetic resonance imaging (MRI). However, these radiological features are not definitive and can overlap with those of malignant cystic tumors of the prostate or pelvis, making a conclusive diagnosis usually possible only after surgical excision and histopathological examination.⁴

Histologically, a giant multilocular prostatic cystadenoma features multiloculated cystic spaces lined by benign prostatic glandular epithelium, with no signs of cytologic atypia or invasive characteristics. Despite its benign pathology, as the cystadenoma enlarges, its symptoms can extend beyond lower urinary tract obstruction, affecting nearby pelvic organs. Although urinary symptoms are the most commonly reported, large tumors can compress the rectum, bladder, and neurovascular structures. In our patient, the advancing disease led to significant rectal compression and persistent difficulties with defecation, emphasizing that this condition should be recognized as a pelvic space-occupying disease rather than merely a urological issue.⁵

A clinically important attribute of this condition is its tendency for recurrence following incomplete surgical resection. Numerous studies indicate that treatments such as cyst marsupialization, transurethral resection, or limited cyst excision often fail to achieve lasting disease control. Comparing previously reported recurrent cases with our own highlights a consistent pattern across all three dimensions: initial surgical choice, time to recurrence, and definitive management. Choi et al. performed laparoscopic marsupialization as the initial approach, resulting in recurrence within 12 months, ultimately resolved by complete re-excision.⁶ Fan et al. similarly reported serial recurrences following two TURPs and a laser prostatectomy before robot-assisted radical prostatectomy achieved durable control.⁷ Abed El Rahman et al. documented a late recurrence 16 years after initial excision, managed by laparoscopic re-excision, underscoring that residual prostatic tissue can regrow over decades under androgenic stimulation.⁸ In our case, robotic cyst excision in 2018 — an inherently incomplete approach — preceded recurrence at seven years, ultimately requiring open radical prostatectomy with en bloc excision for definitive control. Across all cases, the trajectory is the same: conservative or organ-preserving initial surgery defers rather than eliminates recurrence, and complete glandular excision remains the only strategy associated with durable disease control.⁶

Elevated serum prostate-specific antigen (PSA) levels further complicate the management of a giant multilocular prostatic cystadenoma. While PSA is traditionally associated with prostate cancer, elevated levels have been observed in several cases of this condition. This increase is thought to reflect the substantial volume of benign glandular epithelium and chronic inflammatory processes rather than malignant transformation 9, 10, 11. Nonetheless, significantly elevated PSA levels can raise concerns about potential malignancy, prompting extensive diagnostic workups, including repeat imaging and biopsies.

A review of previous literature on such cases has reported several treatment modalities for giant multilocular prostatic cystadenoma, including conservative treatments such as gonadotropin-releasing hormone (GnRH) antagonists,¹² transurethral resection,¹³ enucleation of the prostate, laparoscopic cyst resection,⁸ and partial or complete tumor resections, even radical prostatectomy or pelvic exenteration. Currently, the consensus for management is complete surgical excision.

In our case, given the patient's history of multiple recurrences, significant tumor burden, and progressive symptoms, a radical surgical approach was favored over further conservative management. Therefore, a radical prostatectomy with en bloc excision of the cystic mass was strategically chosen to minimize the risk of recurrence and long-term morbidity. Nevertheless, the current follow-up of three months, while reassuring, does not permit conclusions regarding long-term recurrence-free survival. Published cases have documented recurrence at intervals ranging from 12 months to 17 years following surgical excision, even in cases where resection appeared complete,⁸ highlighting the need for long-term surveillance with serial PSA measurements and periodic pelvic MRI. In our case, postoperative PSA was not obtained, which represents a limitation in the oncologic follow-up documentation.

Finally, our case reinforces the emerging consensus in the literature that complete surgical excision is the cornerstone of durable disease control in GMPC, and that conservative or organ-preserving approaches — regardless of technique — carry a substantial risk of recurrence. Furthermore, given that recurrence has been documented as late as 16 years after apparently complete resection, our experience underscores that three months of follow-up is merely the beginning of a long surveillance journey, and that long-term structured follow-up with serial PSA measurement and periodic imaging is not optional but essential.

4. Conclusion

Giant multilocular prostatic cystadenoma is a rare, benign tumor characterized by a high rate of recurrence due to incomplete removal which can result in severe urinary and gastrointestinal symptoms, including difficulties with bowel movements. For selected patients with recurrent or advanced disease, radical prostatectomy might represent a rational surgical strategy to minimize further recurrence. However, given that late recurrence has been reported after complete resection, long-term surveillance with serial PSA measurement and periodic imaging remains essential.

CRediT authorship contribution statement

Hung Lenh Do: Writing – original draft, Investigation, Conceptualization. Nguyen Hai Dang Le: Writing – review & editing, Writing – original draft. Tan Tinh Chung: Writing – original draft. Tuan Thanh Le: Writing – original draft. Thien Tan Tri Tai Truyen: Writing – review & editing.

Consent

Informed consent has been obtained from our patient.

Author agreement

All authors have seen and approved the final version of the manuscript being submitted.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

None.