Giant multilocular prostatic cystadenoma in a 14-year-old male: A case report

Background: Giant multilocular prostatic cystadenoma (GMC) is a rare, benign tumor that originates from prostatic tissue, comprising of glandular and cystic epithelial tissue. The pelvic mass is typically located within the rectovesical pouch and does not usually invade surrounding tissue, although variations have been reported. Common symptoms include abdominal pain, urinary retention, and dysuria. Reported cases have ranged from 16 to 80 years old, with the first known case described in 1990. Here, we present the case of the youngest patient reported to date with GMC. Case Information: A fourteen-year-old male presented to the Emergency Department (ED), accompanied by his mother, with complaint of severe, intermittent abdominal pain with two episodes of emesis, onset 12 hours prior. The physical exam demonstrated an ill-defined abdominal mass localized over the right lower quadrant. The mass was confirmed on ultrasound, measuring 17.0x13.8x12.3cm, and appearing heterogeneously solid and cystic in nature. MRI demonstrated hydroureteronephrosis with suggestion of bladder compression. Labs showed elevated creatinine, revealing possible obstructive uropathy. To alleviate ureteral and bladder obstruction, the patient underwent attempted placement of bilateral ureteral stents. Once the cystoscopy was performed, however, neither ureteral orifice could be observed. The next day, the patient underwent excision of the pelvic mass. The surgeon identified and removed the multiloculated cystic mass, found within the retropubic space. Approximately two liters of brown fluid was drained from the tumor. The histology was consistent with giant multilocular prostatic cystadenoma. Four months post-excision, MRI demonstrated no evidence of residual lesion and interval resolution of hydroureteronephrosis, and the patient's symptoms had resolved. Conclusion: GMC of the prostate is an extremely rare benign tumor, with less than 40 known cases, and less than five occurring in patients younger than 30. GMC is most likely to be misdiagnosed due to its rarity and heterogenous nature. While most known cases have been treated with surgical excision with good outcomes, there have been cases of recurrence and co-involvement with malignant cells. Therefore, follow-up is vital for these patients. Here, our case further reveals that GMC and tumors alike can occur in the pediatric population, and thus in young males with pelvic masses of unknown origin, CMC should be considered.