病例報告：膀胱前列腺切除術後十年的惡性陰莖異常勃起

廖凡霆、吳俊德、蘇世桓

林口長庚紀念醫院外科部泌尿科

Malignant Priapism 10 Years After Cystoprostatectomy for Urinary Bladder Urothelial Carcinoma: A Rare Case Report

Fan-Ting Liao, Chun-Te Wu, Shih-Huan Su

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

Introduction:

Malignant priapism is a rare, yet serious urological condition characterized by persistent, non-sexual related erections, often associated with primary neoplasm direct invasion or metastasis. Most case reports described active disease with penile metastasis or early recurrence with penile metastasis; however, we present a case of late occurring malignant priapism after no-evidence of disease after initial successful cystoprostatectomy which is suggestive of field cancerization with new second primary in residual distal urethra.

Presentation of Case:

        A 74-year-old man patient was initially presented to our outpatient department due to priapism for since morning and returned to our emergency department due to unresolved priapism 3 days later. The patient had medical history of gouty arthritis, perforated peptic ulcer status post subtotal gastrectomy and Billroth-II gastroduodenostomy 60 years ago, microcytic anemia and history of urinary bladder infiltrating urothelial carcinoma (UBUC) status post robotic assisted radical cystoprostatectomy with uretero-ileal cutaneous diversion 10 years ago. Initial pathology disclosed pT1 during first transurethral resection and final pathology from cystoprostatectomy disclosed residual pTa disease with negative margin and absence of lymphovascular invasion. During follow up for UBUC, the patient had episodes of hematuria from native urethra with fiberscope survey showing negative results and had been declared no-evidence of disease a year ago. The patient had penile pain relating to priapism and there were no other symptoms of dysuria, hematuria from native urethra, nor scrotal or inguinal lesions. Upon physical examination, penile hard erection, penile shaft irregular surface and severe penile tenderness were observed. Bedside penile echography disclosed normal blood flow of bilateral corpus cavernosa and aspiration was done 2 times with sampling for cavernosal blood gas analysis, partial pressure of oxygen (PO₂) 75.6mmHg. Results were suggestive of non-ischemic type priapism and biopsy was suggested to rule out neoplasm due to irregular contour; however, patient refused during first admission episode and was discharged with improved pain and still erected penis.

        Priapism with penile pain persisted and patient returned to our emergency department 2 days later. T-shunt was performed for priapism and penile biopsy done over glans and bilateral cavernosum. Dorsal slit of prepuce was also done due to severe phimosis. Post-operative symptomatic improvement was noted with still residual stiffness over proximal penile shaft. There had been minor intermittent wound bleeding and patient discharged smoothly on post-operative day 8. Pathology reported metastatic urothelial carcinoma with invasive nests and focal lymphatic permeation for glans and bilateral cavernosum biopsies. Around one month later, the patient was admitted third time and received total penectomy. Surgical pathology disclosed high grade urothelial carcinoma in the

penile glans, shaft, penile urethral, the corpora cavernosa and corpus spongiosum, with close surgical margin at ventral resection otherwise negative margin involvements. The patient discharged under acceptable condition at post-operative day 8.

        Afterwards, the patient was referred to Oncologist where image survey also shown bone and nodal metastasis. Salvage chemotherapy of gemcitabine was completed. However, the patient was further admitted for scrotal and right inguinal soft tissue infection and during hospitalization generalized tonic-clonic seizure episode occurred. Brain magnetic resonance angiography was arranged by Oncologist with results of superior cerebellum metastasis. Poor and drowsy conscious with impaired Glasgow coma scale (E3V3M6) and also left side weakness developed, imminent poor prognosis was anticipated.

Discussion:

Priapism, a condition characterized by prolonged and often painful erections lasting more than 4 hours, poses a significant medical challenge due to its diverse etiologies and potential complications. While typically associated with conditions like sickle cell disease in children and pharmacological agents in adults, priapism seldomly can also arise secondary to malignancies. Malignant priapism, a manifestation of penile metastases from systemic cancers, presents unique diagnostic and therapeutic dilemmas even to current days.

Penile metastases could arise from various primary tumors and the most frequent primary sites being genitourinary tract (70%) and gastrointestinal system (23%), with predominantly bladder (28.6%) and prostate (27.9%) cancers. Common clinical features included indurated nodules, penile masses, or the hallmark presentation of malignant priapism, which is estimated to affect 20%-50% of patients across series. The exact mechanism behind malignant priapism remains undetermined and current hypothesis comprise of spread to the corpora cavernosa by direct extension, retrograde venous or lymphatic transport, and arterial embolism. Priapism is due to compromised penile hemodynamics, including hyper-viscosity of blood and accentuation of the cavernous outflow in hematologic malignancies, obstruction cavernosa outflow by tumor directly or thrombus, irritation of the neural pathways and cavernosa arterial rupture by tumor invasion. Both low flow and high flow priapism had been described in malignant priapism. Diagnostic cavernosal blood gas analysis could help to distinguish between ischemic and non-ischemic types and aid in treatment planning, while penile ultrasonography with or without duplex could also provide clinical information. Final confirmation would be made by pathological diagnosis with penile biopsy.

Management of malignant priapism presents significant challenges, often requiring a multidisciplinary approach tailored to individual patient characteristics and disease stage. Current treatment strategies encompass a spectrum of interventions, including conservative measures like pain control, systemic therapy, and invasive procedures such as shunting and penectomy. However, the optimal management approach remains unclear, necessitating individualized treatment decisions guided by clinical judgment which ultimately should prioritize symptom control and quality of life, considering the advanced age and poor prognosis often associated with underlying malignancies. There is a strong need for further research to refine diagnostic algorithms and therapeutic strategies.

Another interesting point would be the late occurrence of malignancy priapism of urothelial carcinoma in our case, as primary urothelial carcinoma is generally with high early recurrence rate. Molecular evidence had provided support of field cancerization effect precipitated by carcinogens which could explain the late onset of recurrent urothelial carcinoma of distal urethra in our case. Literature review and review of cases of penectomy in our institution had no precedents, one case reported by Ahmed (2012, Medicine & Health Rhode Island) reported priapism in early recurring urothelial carcinoma 3 months after cystoprostatectomy.

Conclusion:

        Malignant Priapism is a rare entity which had been managed through different methods including conservative treatment, shunting and partial or total penectomy. Itself is an indicator of poor prognosis with life expectancy less than 1 year despite current modalities of management. In the presence of malignancy, the usual algorithm for priapism is unpractical and there is no guidance on optimal treatment and individual efficacies relating to life quality nor cancer-specific survival due low volume cases. It is a topic yet to be investigated.