Relevance of computed tomography and magnetic resonance imaging for penile metastasis after prostatectomy: uncommon case report and brief review of the literature

Solitary Prostate Carcinoma Penile Metastasis on 18 F-DCFPyL PET/CT

ABSTRACT

An 83-year-old man was referred for an 18 F-DCFPyL PET scan for the evaluation of rising serum prostate-specific antigen level on the background of previous radical prostatectomy for prostate adenocarcinoma and urinary outflow tract obstruction requiring in-dwelling catheter insertion. The PET scan demonstrated focal increased activity (SUV max , 35.7) at the dorsal aspect of the mid penile shaft, with histopathological confirmation of penile metastasis from primary prostate cancer.

Penile metastasis in prostate cancer patients: Two case reports, surgical excision technique, and literature review

Two cases of penile metastasis from primary prostate cancer in a single center are presented, along with a literature review and description of the excision technique. Despite its rich vascularization, penile metastasis is rare, with 72 new cases from September 2006 to March 2021. There is a wide variety of diagnoses, treatments, and prognoses for penile metastatic lesions. Ga-68 prostatespecific membrane antigen positron emission tomography/computed tomography is the most sensitive imaging tool for detecting metastasis from primary prostate cancer. Magnetic resonance imaging of the penis is the most reliable technique for differentiating penile lesions. Histological diagnosis is mostly performed using fine-needle biopsy aspiration. Metastasis-directed treatment is not considered to contribute to prolonged survival. Local treatment is feasible and can be offered to symptomatic patients. Owing to a heterogeneous group, defining overall survival is difficult. Survival until 46months after detecting penile metastases is described.

A Case of Penile Metastasis from Prostate Cancer, Identified by 68Ga-PSMA PET/CT, Mimicking Peyronie's Disease: A Diagnostic Challenge

A 70-year-old man with high-risk prostate cancer (PCa) received radiation therapy and androgen deprivation therapy (ADT). The patient developed penile tenderness, compatible with Peyronie's disease upon physical examination. An ultrasound revealed a matching hypoechoic plaque and a thrombus in the vena dorsalis profunda, which were treated with anticoagulants. A follow-up ultrasound showed no abnormalities. Despite the use of analgesics, the patient suffered from persistent pain, later accompanied by an increasing PSA level of up to 7.5 ng/mL, despite ADT. 68Ga-PSMA PET/CT showed a PSMA uptake consistent with PCa penile metastasis. Due to severe pain and the presence of metastatic PCa, the patient was referred for penectomy. Histopathological analysis confirmed metastases originating from the PCa. This case underscores the importance of 68Ga-PSMA PET/CT in diagnosing PCa metastases and vigilance towards urogenital symptoms as potential indicators of metastases, despite the rarity of penile metastases.

Penile metastasis from prostate cancer misdiagnosed as Peyronie disease: a case report

Introduction

Penile metastases from prostate cancer are rare, and patients’ prognosis and survival rates are low. Conservative treatment is usually recommended for such patients with an emphasis on improving their quality of life.

Aims

The aims were to raise awareness of penile metastasis from prostate cancer and Peyronie disease among physicians and other health care professionals, as well as to provide a useful experience for future diagnosis and treatment.

Methods

The current case report is based on patient self-report and a literature review. Written informed consent was obtained from the patient.

Results

We report the case of a 68-year-old man who was admitted with a complaint of urinary retention. Preoperative examination and ancillary tests showed a 2.0-cm-long hard nodule palpable on the dorsal aspect of the penile root, which was misdiagnosed as Peyronie disease. However, a biopsy of the penile scleroma was performed, and the final pathology finding confirmed the diagnosis of penile metastasis from prostate cancer. The patient opted for continuous androgen deprivation therapy (abiraterone) and systemic chemotherapy (docetaxel and cisplatin). He was treated for 2 cycles and had no specific discomfort during chemotherapy, except for significant gastrointestinal reactions, hypocellularity, and hair loss symptoms.

Conclusion

This report describes a rare case of penile metastasis from prostate cancer, which was initially misdiagnosed as Peyronie disease, indicating that clinicians need to improve their understanding and discrimination of this disease.

Atypical Metastases in the Abdomen and Pelvis From Biochemically Recurrent Prostate Cancer: 11C-Choline PET/CT Imaging With Multimodality Correlation

PET imaging with targeted radiotracers has become integral for mapping the location and burden of recurrent disease in patients with biochemical recurrence (BCR) of prostate cancer (PCa). PET with 11C-choline is part of the National Comprehensive Cancer Network and European Association of Urology guidelines for evaluation of BCR. With advances in PET technology, increasing use of targeted radiotracers, and improved survival of patients with BCR due to novel therapeutics, atypical sites of metastases are being increasingly encountered, challenging the conventional view that PCa rarely metastasizes beyond bones or lymph nodes. We describe such atypical metastases in the abdomen and pelvis on 11C-choline PET (including in the liver, pancreas, genital tract, urinary tract, peritoneum, and abdominal wall, as well as perineural spread), presenting multimodality imaging features and relevant imaging pitfalls. Given atypical metastases' inconsistent relationship with serum PSA and non-specific presenting symptoms, they are often first detected on imaging. Awareness of their imaging features is important as their detection impacts clinical management, patient counseling, prognosis, and clinical trial eligibility. Such awareness is particularly critical as the role of radiologists in the imaging and management of BCR will continue to increase given the expanding regulatory approvals of other targeted and theranostic radiotracers.

Case Report: 18F-PSMA PET/CT May Improve the Clinical Management of Penile Metastases From Prostate Cancer

Metastases from prostate cancer (PCa) to the penis are extremely rare, and few case reports exist in the literature. Because most patients usually present with multiple distant metastases at diagnosis, the prognosis is very poor. With the wide application of prostate-specific membrane antigen (PSMA) PET/CT, penile metastases may be detected at an early stage. Thus, questions regarding whether early diagnosis and precise treatment will equate to a survival advantage have recently been raised. In the present study, we reported 3 cases of penile metastasis from castration-resistant PCa. Moreover, a patient with asymptomatic penile metastases was diagnosed by ¹⁸F-PSMA PET/CT followed by lesion biopsy, and the prognosis was very well, despite with an aggressive pathological feature and low treatment intensity. In addition, we performed a literature review and found 62.5% of asymptomatic penile metastases were diagnosed by PSMA PET/CT in past seven years. Thus, we believe that PSMA PET/CT may detect more asymptomatic penile metastases in future, which led to early diagnosis, treatment and survival advantage.

A rare case of penile metastases from small cell prostate cancer

We present a case of an 83-year-old-male with painless penile nodules several months after he was diagnosed with pure prostatic small cell carcinoma. Penile doppler ultrasound and magnetic resonance imaging demonstrated solid nodules in both corpora cavernosa. Fine-needle aspiration of the nodules with immunohistochemical examination confirmed prostatic small cell carcinoma origin of metastases. Small cell carcinoma of the prostate is a rare disorder accounting for less than 1% of all prostate cancers, the penis being an uncommon site for metastasis. An extremely low number of cases of penile metastases from prostatic small cell carcinoma has been reported to date in the literature.

Current Imaging Techniques for and Imaging Spectrum of Prostate Cancer Recurrence and Metastasis: A Pictorial Review

Relapsing level of prostate-specific antigen (PSA) after initial curative-intent local therapy for organ-confined prostate cancer is often the first sign of recurrence. However, PSA level recurrence does not enable accurate differentiation of locally recurrent tumor from metastatic disease or a combination of both. Metastatic prostate cancer most frequently involves bones and lymph nodes, followed by other organs such as the liver, lung, pleura, adrenal gland, ureter, peritoneum, penis, testis, and meninges. Conventional imaging including CT and bone scintigraphy has long been the standard of care but has limited sensitivity in depicting early local recurrence or metastatic disease. Multiparametric MRI has been shown to be more sensitive in detecting locally recurrent tumor in the prostatectomy bed as well as in situ recurrence in a prostate gland that has been treated with radiation therapy or thermal ablation. In addition, lesions detected with multiparametric MRI may be amenable to targeted biopsy for definitive diagnosis of recurrence. PET/CT or PET/MRI using the U.S. Food and Drug Administration (FDA)-approved tracers carbon 11 choline or fluorine 18 fluciclovine has demonstrated markedly increased sensitivity and specificity for diagnosis of early metastatic disease such as small-volume lymph node metastasis, as have a range of investigational gallium 68 prostate-specific membrane antigen (PSMA) radioactive PET tracers. With recent advances in imaging modalities and techniques, more accurate early detection, localization, and characterization of recurrent prostate cancer have become possible. The authors present a contemporary review of the strengths and limitations of conventional and advanced imaging modalities in evaluation of patients with recurrent prostate cancer and a systematic review of the clinical and imaging features of locally recurrent and metastatic disease.^©RSNA, 2020See discussion on this article by Barwick and Castellucci.