Prostatic adenocarcinoma presenting with metastases to the testis and epididymis: A case report

Introduction

Prostate cancer is the most commonly diagnosed solid malignancy that occurs in the Western male population, with an incidence rate that is continually increasing (1). Prostate cancer is the sixth leading cause of cancer related mortality in males, worldwide (2); annual global mortality rates increased from 156,000 to 256,000 mortalities between 1990 and 2010 (3). Patients diagnosed with prostate cancer usually exhibit one or more symptoms, including frequent urination, nocturia, difficulty starting and maintaining a steady stream of urine, hematuria and dysuria. Prostate cancer is diagnosed by biopsy. Medical imaging may then be performed to determine if the cancer has spread to other parts of the body (4). Approximately 8% of all prostate cancers are diagnosed at an advanced stage (5). Bone and lung metastases from prostate cancer are common, but metastases to both the testis and epididymis are rare, with a usually poor prognosis (6). The treatments for prostate cancer include a combination of surgery, radiation therapy, hormone therapy and chemotherapy. Patient outcome depends on the patient's age and general medical condition, as well as how aggressive and extensive the cancer is (7). The current study presents the case of a 69-year-old male who was diagnosed with synchronous testicular and epididymal metastases from a high-grade prostate carcinoma, without distant metastasis. To the best of our knowledge, such a case has seldom been described in the literature. Written informed consent was obtained from the patient.

Case report

In July 2012, a 69-year-old male was admitted to The First Hospital of Shijiazhuang (Shijiazhuang, China) with a 2-year history of lower urinary tract symptoms, including increased frequency of urination, noturia and a weak urinary stream, without dysuria or hematuria. In a routine examination 1 month prior to admittance, it was found that the patient's serum prostate-specific antigen (PSA) level was >100 ng/ml (normal range, <4.0 ng/ml). The patient's medical history included 24 years of diabetes treated with insulin (fasting glucose level of 6.55 mmol/l; normal range, 3.89–6.1 mmol/l) and a 20-year history of hypertension that was treated with benazepril and metoprolol. The patient had undergone a prostate transurethral resection five years previously due to prostate bleeding. The current prostate pathology showed prostatic hyperplasia. The patient also had a history of smoking 10 cigarettes per day for 40 years.

Physical examination showed that the right testicle was slightly enlarged and tough, without tenderness. No abnormalities were found in the spermatic cord and left testicle. B-mode ultrasound showed prostatic hyperplasia with calcification (51×63×58 mm). An increased post-void residual urine volume of 110 ml (normal range, 5–12 ml) was noted. The kidneys, ureters, bladder, liver and spleen were normal. Magnetic resonance imaging revealed prostate carcinoma with seminal vesicle involvement. A prostate biopsy revealed prostate gland adenocarcinoma, with a Gleason score of 3+3 (8). Immunohistochemical staining showed strong positive staining for prostatic acid phosphatase (PAP) (+++), PSA (+++) and P504s (+++), but not for p63 (−)or CK34βE12 (−) (9). The Ki-67 was ~5%. A metastatic evaluation of the chest, abdomen, pelvis, bones, kidneys, ureters, bladder, liver and spleen were negative. The patient was treated with a bilateral orchiectomy. The testicular pathology showed that the right testicle, the tunica albuginea and the epididymis were infiltrated by metastatic adenocarcinoma (Figs. 1 and 2); microscopically, malignant round tumor cells were observed within the interstitium of the testicular parenchyma beneath the capsule. The cells had infiltrated the seminiferous tubules and exhibited a discohesive growth pattern. Immunohistochemical staining once again showed strong positive staining for PAP (+++), PSA (+++) and P504s (+++). The left testis and epididymis were normal.

Figure 1. Neoplasm infiltrating the testicular tissue with adenocarcinoma. The white arrow indicates the tunica albuginea, which was invaded by prostatic adenocarcinoma. The black arrow indicates the prostate adenocarcinoma (hematoxylin and eosin staining; magnification, ×10).

Figure 2. Neoplasm infiltrating the epididymal duct with adenocarcinoma. The white arrow indicates the epididymal duct, with carcinoma invasion around the duct. The black arrow indicates the prostate adenocarcinoma tissue (hematoxylin and eosin staining; magnification, ×10).

The patient was treated with ongoing conventional flutamide (250 mg, 3 times/day) endocrine therapy and radiotherapy (60 Gy/30 fractions 5 times/week) for 6 weeks, and currently remains in a stable condition after follow-up for 24 months.

Discussion

Prostate cancer is a common cancer in older men (10). With changes in life style, diet and environment, as well as the improved detection level, the incidence of prostate cancer has recently increased (11). The majority of prostate cancer is adenocarcinoma, usually occurring in the peripheral zone of the prostate (12). Prostate cancer may spread through the lymph and blood vessels, or through direct invasion to adjacent organs. Blood transfer accounts for 35% of this spread. The most common sites of metastases are the bones, lungs, liver, pleura and adrenal glands (13), while the occurrence rates of metastases in the testes and epididymis are low. Johansson and Lannes showed that ~4% of metastases to the testes are found incidentally during orchiectomy for advanced prostate carcinoma (14). Following the examination of 24,000 autopsy results, Pienkos and Jablokow reported a testicular metastasis rate of 0.06% (15). However, asymptomatic metastases of prostate carcinoma to both the testis and the epididymis are extremely rare occurrences; only a small number of cases have been reported previously (1,2). Thon et al (16) reported a case of carcinoma of the prostate in a German patient who exhibited metastases to the testis and epididymis. However, to the best of our knowledge, to date no cases of such have been reported in Asia. Prostate cancer metastasis to the testes usually lacks symptoms and signs, and can only can be incidentally detected during autopsies, or following a bilateral orchiectomy for hormonal management in cases of advanced prostate carcinoma. Prostate carcinoma may spread to the testes or epididymis by retrograde venous diffusion, arterial embolism, retrograde lymphatic spread or direct extension via the vas deferens (14,15).

The prognostic significance of testicular metastasis from prostate carcinoma remains unknown. The study by Tu et al suggested that prostate cancer with testicular metastasis is equally sensitive to endocrine and radiation therapy (17). The mean sensitive period for endocrine treatment is 33 months, while the mean lifetime of prostate cancer patients following diagnosis is 78 months (14). The present patient had been treated with endocrine therapy and radiation therapy for 1 month, and the serum PSA level was slowly being reduced. However, after 1 year of treatment with endocrine therapy, the patient's serum PSA level returned to normal. The patient remains under close follow-up.

Acknowledgements

This study was supported by grants from the National Natural Science Foundation of China (no. 31171097), the Natural Science Foundation of Hebei Province (no. C2014206419), the Hebei Province Overseas Returnees Start-up Fund (no. C2012003031) and the Research Project of Science and Technology of Higher Education of Hebei Province (nos. ZD2015007 and Z2015005).

References