Hybrid Open and Robot‐Assisted Excision of a Giant Multilocular Prostatic Cystadenoma With Unusual Dorsal Growth: A Case Report

Large prostatic tumors are rare conditions that may present with atypical morphology on imaging studies and can pose substantial challenges in preoperative diagnosis. We encountered a case of giant multilocular prostatic cystadenoma (GMPC) with dorsal growth in which malignancy could not be excluded despite multiple biopsies demonstrating stromal hyperplasia. A 71‐year‐old man presented with lower abdominal pain associated with defecation, and imaging revealed a large pelvic mass with increased uptake on positron emission tomography. Because malignancy could not be excluded, radical prostatectomy was performed. The procedure was initiated robotically but required conversion to an open approach due to intraoperative difficulty. Histopathological examination of the 500‐g resected mass revealed stromal hyperplasia with multilocular cystic architecture, consistent with GMPC. Postoperatively, urinary function remained satisfactory, and no recurrence has been observed to date. This case highlights the diagnostic challenges associated with GMPC presenting with atypical growth patterns and demonstrates that complete excision is feasible with an appropriate surgical approach.