Giant multilocular prostatic cystadenoma

Abstract

Background: The giant multilocular prostatic cystadenoma is a very rare benign tumor of the prostate gland. It is composed of predominantly cystic enlarged prostatic glands in a fibrous stroma and spreads extensively into the pelvis. Because of the large size at the time of diagnosis, it is not always possible to determine the exact point of origin for these multilocular cystic neoplasms. Thus, diagnosis before histological examination of a surgical specimen is often difficult. Here, we present a case involving one of the largest giant multilocular prostatic cystadenomas reported in the literature and discuss preoperative diagnoses and appropriate surgical approaches for this rare retroperitoneal tumor.

Case presentation: A 50-year-old man presented with a 2-year history of abdominal distension and lower urinary symptoms. Enhanced CT showed a large retroperitoneal mass with multiple septations in the pelvis and lower abdomen, measuring 30 cm in size, surrounding the rectum and displacing the bladder, prostate, and seminal vesicle to the right anterior side. MRI showed multiple cysts with a simple fluid appearance on T2-weighted images and enhanced solid components on gadolinium-enhanced fat-saturated T1-weighted images, suggesting the retroperitoneal mass as leiomyoma with cystic degeneration or perivascular epithelioid cell tumor. Biopsy of the mass showed a spindle cell tumor with focal smooth muscle differentiation. Differential diagnosis comprising leiomyoma, low-grade leiomyosarcoma, and perivascular epithelioid cell tumor was made. Complete resection of the tumor with low anterior resection of the rectum was performed. The tumor was solid with multilocular cavities containing blackish-brown fluid and measured 33 × 23 × 10 cm. Histologically, the tumor was composed of variously sized dilated glandular structures lined by prostatic epithelia surrounded by fibromuscular stroma. The prostatic nature of the lesions was confirmed by immunohistochemical staining of the epithelium for prostate-specific antigen. Thus, pathological diagnosis was a giant multilocular prostatic cystadenoma.

Conclusions: We present our experiences with one of the largest giant multilocular prostatic cystadenomas. When a retroperitoneal huge lesion with locular cavities fills the pelvis in a male patient, the possibility of giant multilocular prostatic cystadenoma should be considered before planning for retroperitoneal tumor treatment.

Keywords: Giant multilocular prostatic cystadenoma; Prostatic tumor; Retroperitoneal tumor.

Fig. 1

Enhanced abdominal CT. a, b, c A large multilocular mass with soft tissue component displacing the bladder (*) and rectum anterolaterally. d The arrow shows the prostate

Fig. 2

a, b T2-weighted MRI. Most cysts showed high intensity suggesting simple fluid, and some showed the presence of layering which suggests the likelihood of either fat or blood in content. The arrowheads show the presence of layering within the cystic areas. c, d Non-enhanced fat-saturated T1-weighted MRI and e, f gadolinium-enhanced fat-saturated T1-weighted MRI. Several solid components were enhanced

Fig. 3

Intraoperative view. Large mass with a smooth surface in the lower abdomen and pelvis

Fig. 4

Gross photograph. Sectioning revealed a multicystic cut surface

Fig. 5

Pathological examination of the resected specimen. a Low-power magnification of cystadenoma of the prostate with dense fibromuscular stroma (H&E, original magnification × 20). b Cystic dilated glandular structures surrounded by a fibrous stroma resembling prostatic hyperplasia (H&E, original magnification × 20). c Glands and cysts are lined by cuboidal to low columnar epithelial cells with basally located nuclei (H&E, original magnification × 40). d The epithelium of the cysts stained positively with prostate-specific antigen stain (× 20)