Giant prostatic hyperplasia - A rare entity

Clinical History

A 45-year-old male patient presented with a history of difficulty in passing urine for 1 month, insidious in onset, gradually progressive. On per-rectal examination there was a firm to hard mass palpable in the anterior wall. Patient was referred for USG abdomen, then subsequently CECT abdomen and pelvis.

Imaging Findings

Ultrasound abdomen was performed, which showed a large well-encapsulated homogeneous soft tissue mass lesion at the neck of the urinary bladder in the region of the prostate, measuring 10.2x11.3x5.6 cm (volume: 583ml). Significant post-void residual volume of 80 ml was present in the bladder.
The patient underwent CECT abdomen and pelvis, which showed a large well-defined globular, solid, heterogeneously enhancing soft tissue density mass lesion measuring approximately 10.4x9.8x10 cm in the pelvis, in the region of the prostate, causing mass effect on the urinary bladder and rectum. The lesion was compressing the bilateral distal ureters, causing mild hydroureteronephrosis. Predominant blood supply to the lesion was from bilateral internal iliac arteries.
MRI showed homogenously T2 iso to hyperintense soft tissue mass lesion in the region of the prostate.
The patient underwent transrectal prostate biopsy which revealed no malignant features. We performed simple suprapubic prostatectomy and the prostatic mass was removed en bloc successfully. Final biopsy report revealed benign prostatic hyperplasia.

Discussion

Benign prostatic hyperplasia (BPH) in men is commonly associated with the ageing process. Prostatic hyperplasia is considered to be due to the proliferation of epithelial and stromal cells, impairment of programmed cell death (apoptosis) or both, and to be endocrine-controlled.

Autopsy data indicate that over 90% of men older than 80 years have histological evidence of BPH. Prostates weighing more than 100 g have been recorded in only 4% of men above the age of 70 years. In some people, the prostate enlarges massively, eventually weighing more than 500 g, which is defined as giant prostatic hyperplasia (GPH).

Researchers have not identified to date any specific cause for this massive enlargement of the prostate. The genesis of GPH is not known, however, an exaggerated over-expression of growth factors combined with the absence or reduction of inhibitory factors have been proposed as possible mechanisms. The mutation of certain proto-oncogenes such as
Ras and c-erbB-2 may also be involved, developing a continuous cellular proliferation signal or the loss of influence of the p53 suppressor gene through its mutation or deletion, which would allow for abnormal cell proliferation. [1-6]

Prostate growth and the severity of its symptoms are erratic in each case. Known as prostatism, these clinical symptoms are characterized by the presence of irritative and obstructive lower urinary tract symptoms (LUTS). In this regard, it is fundamental to remember that prostate size is not directly proportional to degree of symptom severity.

Severe prostatic hyperplasia is confirmed by imaging studies such as US, tomography and magnetic resonance, though they can be imprecise in defining tumour origin. [4]

Giant benign prostatic hyperplasia is an extremely rare entity and the mechanisms of its genesis are not known. The fact that there is a greater stromal component in these large prostates explains the lack of PSA elevation over 25 ng, a condition that could perhaps be expected due to the known volume/PSA relation in the benign pathology of the prostate. [4] The PSA level of our patient was 22.05 ng/ml (normal: 4ng/ml)

The surgical procedures that have been recommended to remove the giant prostate are simple suprapubic and retropubic prostatectomy. [3]

Differential Diagnosis List

Final Diagnosis

Giant benign prostatic hyperplasia

URL:	https://www.eurorad.org/case/12469
DOI:	10.1594/EURORAD/CASE.12469
ISSN:	1563-4086