攝護腺類澱粉沉積症：個案及文獻回顧

洪瑞陽¹、廖凡霆²、莊正鏗²、邵翊紘²

¹馬偕醫學院；

²林口長庚紀念醫院泌尿外科,長庚大學

Prostate Amyloidosis: A Case Report and Literature Review

Jui-Yang Hung¹, Fan-Ting Liao², Cheng-Keng Chuang², I-Hung Shao²

¹Mackay Medical College

²Division of Urology, Department of Surgery, Linkou Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan

Purpose:

Amyloidosis is a rare disease which deposits of amyloids may occur in many different organs, with potential severe consequences. End-stage-diseases of cardiac amyloidosis and renal amyloidosis may result in mortality. We present a case of prostate amyloidosis in a male with refractory hemospermia and elevated PSA.

Presentation of Case:

        A 60-year-old male was presented to our urology outpatient department (OPD) with complaint of hemospermia persisting for one year. His medical history included left bullous keratopathy, pseudophakia status post-cornea transplantation, and a history of urolithiasis treated with extracorporeal shock wave lithotripsy in June 2023 at local hospital.

    Upon history taking, the patient had complained of hemospermia for one year accompanied with hematuria, dysuria, nocturia 2-3 times per night and dribbling. Digital rectal examination revealed a mildly enlarged prostate with elastic consistency. Initial urine analysis showed hematuria and pyuria. His PSA levels were measured at 9.17 ng/mL, with a free PSA of 1.27 ng/ml. Transrectal ultrasound of the prostate showed enlarged prostate (32cc) with heterogenous echogenicity. KUB revealed the presence of renal stones. Oral cefuroxime was prescribed based on urine culture susceptibility test ( E Coli)

One month later, due to persistence of hemospermia, hematuria and rising PSA (12.98 ng/mL) Intravenous pyelogram (IVP) was performed which revealed left lower calyceal stones and segmental irregular contour of the right upper ureter at L4 level with no obvious obstructive uropathy. Right ureterorenoscopy and TRUS prostate biopsy was arranged. Ureteroscopy demonstrated a focal narrow lumen in the right upper ureter, with no apparent tumors observed. Prostate biopsy results revealed benign prostatic tissue and amorphous material deposits surround few glands. Further special stain showed salmon color on Congo red exhibiting apple green birefringence under polarized light. These characteristics confirmed the presence of amyloid deposits in the prostate and diagnosis of prostatic amyloidosis.

Subsequent OPD follow-up included cardiac echocardiography, which showed a left ventricular ejection fraction (LVEF) of 74% with normal wall motion. Additionally, a whole-body MRI was scheduled to screen for systemic amyloidosis.

Discussion:

Systemic amyloidosis, characterized by the extracellular deposition of amyloid fibrils, is a rare disease that can affect multiple organs, leading to organ dysfunction. Although its precise incidence remains poorly documented, estimates suggest it ranges between 5 and 13 cases per million individuals annually.

The prostate, being part of the genitourinary system, is susceptible to amyloid deposition. However, prostate amyloidosis typically presents with nonspecific symptoms. Given the increasing prevalence of benign prostatic hyperplasia (BPH) and prostate cancer with age, there has been a rise in prostate-related procedures such as biopsies and prostatectomies. Consequently, prostate amyloidosis is often diagnosed incidentally during these procedures.

Diagnosis of amyloidosis is confirmed by the characteristic green birefringence observed under congo red staining. The most common subtypes encountered in prostate amyloidosis include AL, ATTR, and Asem1. While Asem1 subtypes are often localized, AL and ATTR subtypes tend to manifest as systemic diseases, with prognosis heavily influenced by cardiac involvement.

Interestingly, in previous studies, prostate amyloidosis has been observed as the initial site of involvement in systemic amyloidosis. Early detection of systemic amyloidosis, often facilitated by the identification of prostate amyloidosis, enables timely intervention and treatment.

Once prostate amyloidosis is identified, it becomes imperative to conduct a comprehensive evaluation to differentiate between systemic and localized forms of the disease. Further evaluation in cases of suspected cardiac amyloidosis includes heart echocardiography to assess cardiac function. Whole-body MRI or PET to identify potential involvement of other organs beyond the prostate gland. Regular outpatient department (OPD) follow-ups are essential for monitoring disease progression and response to treatment.

Conclusion:

    Prostate amyloidosis is a rare condition and is frequently diagnosed incidentally, often during procedures such as biopsies or prostatectomies performed for other reasons. Localized prostate amyloidosis may not pose significant health risks, but the possible presence of systemic amyloidosis should not be ignored. Systemic amyloidosis can lead to organ dysfunction and serious health implications. Therefore, it's important to conduct regular surveillance and follow-up for early detection of potential progression to systemic disease.