Prostate penile metastasis: Incidence and imaging pattern on 68 Ga-PSMA PET/CT

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.

Unusual Case of Missed Penile Metastases on 68Ga-PSMA PET/CT

ABSTRACT

A 75-year-old man with a history of previously treated localized prostate cancer and prostate-specific antigen of 4.86 ng/mL was referred for a 68Ga-prostate-specific membrane antigen PET/CT. PET imaging was reported to be negative. After subsequent review and re-read of the scan, prostate-specific membrane antigen imaging revealed uptake along the penile shaft (SUVmax of 14.7). MRI was compatible with tumor. Penile metastases from prostate cancer, although uncommon, do occur and readers are encouraged to distinguish penile metastatic uptake from residual urine in the urethra.

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.

Unexpected Metastatic Localizations of Prostate Cancer Determined by 68Ga PSMA PET/CT: Series of Four Cases

Prostate-specific membrane antigen (PSMA) is a transmembrane protein with overexpression in most prostate cancer cells. Gallium-68-(⁶⁸Ga) PSMA positron emission tomography/computed tomography (PET/CT) imaging is a game-changer in the management of prostate cancer. ⁶⁸Ga PSMA PET/CT scan is advanced and a promising radioligand has high sensitivity in determining lesions of prostate cancer with a high tumor to background ratio. The most common areas of metastasis are the bone and pelvic lymph nodes. The prognosis of prostate cancer is mainly determined by the status of metastases. The presence and the localization of metastases affects treatment planning. In our cases, we presented some examples of uncommon sites of metastases such as the brain, adrenal glands, penis and orbit. Improvements in imaging techniques, such as ⁶⁸Ga PSMA PET/CT have led to the possibility to make more determi nation of rare metastase sites in prostate cancer patients.

Solitary Penile Metastasis from Prostate Cancer on 18F-Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography

We report a case of a 66-year-old man with prostate cancer who underwent 18F-prostate-specific membrane antigen positron emission tomography/computed tomography for baseline staging that revealed primary lesion in prostate gland along with a solitary metastatic deposit in the penile shaft. Penile metastasis is rare and usually associated with widespread metastatic disease. Solitary penile metastasis is even rarer and can present as a unifocal, multifocal, or diffuse lesion. Early detection is important in guiding treatment and preventing complications.

18F-rhPSMA-7 PET for the Detection of Biochemical Recurrence of Prostate Cancer After Curative-Intent Radiation Therapy: A Bicentric Retrospective Study

This bicentric, retrospective analysis investigated the efficacy of PET/CT with a novel theranostic prostate-specific membrane antigen (PSMA)--targeting ligand, ¹⁸F-rhPSMA-7, in patients with biochemical recurrence (BCR) of prostate cancer after curative-intent primary radiotherapy. Methods: Datasets from patients with BCR of prostate cancer after external-beam radiation therapy or brachytherapy who underwent ¹⁸F-rhPSMA-7 PET/CT at either Technical University Munich or Ludwig-Maximilians-University Munich were retrospectively reviewed by experienced nuclear medicine physicians and radiologists at both centers. The median injected activity was 299 MBq (range, 204-420 MBq), and the median uptake time was 77 min (range, 46-120 min). All lesions suggestive of recurrent prostate cancer were noted. Detection rates were correlated with patients' prostate-specific antigen (PSA) level, primary Gleason score, and prior use of androgen-deprivation therapy (ADT). Results: Ninety-seven patients were included (65 at Technical University Munich and 32 at Ludwig-Maximilians-University Munich). The median prescan PSA was 4.19 ng/mL (range, 0.1-159 ng/mL). The primary Gleason score was ≤6 in 19 patients, 7 in 25, ≥8 in 33, and unknown in 20. Thirty patients received ADT in the 6 mo preceding PET/CT. ¹⁸F-rhPSMA-7 identified lesions in 91 of 97 (94%) patients. Detection rates stratified by PSA were 88% (22/25), 97% (30/31), 90% (19/21), and 100% (20/20) for a PSA of <2, 2-<5, 5-<10, and ≥10 ng/mL, respectively. Detection rates in the subgroup of patients not meeting the Phoenix criteria for BCR were 80% (4/5), 90% (9/10), 100% (4/4), and 83% (5/6) for a PSA of <0.5, 0.5-<1, 1-<1.5, and 1.5-2 ng/mL, respectively. There were no significant differences in detection rates between patients with and without prior ADT (100% vs. 91%, P = 0.173) or patients with a Gleason score of ≤7 and a Gleason score of ≥8 (98% vs. 91%, P = 0.316).¹⁸F-rhPSMA-7 revealed local recurrence in 80% (78/97); pelvic lymph node metastases in 38% (37/97); retroperitoneal and supradiaphragmatic lymph node metastases in 9% (9/97) and 4% (4/97), respectively; bone metastases in 27% (26/97); and visceral metastases in 3% (3/97). In the subgroup of patients with a PSA of <2 ng/mL above nadir, local recurrence occurred in 76% (19/25) and pelvic lymph node metastases in 36% (9/25). Conclusion:¹⁸F-rhPSMA-7 PET/CT demonstrates high detection rates in prostate cancer patients with BCR after primary radiation therapy, even at low PSA values. Its diagnostic efficacy is comparable to published data for other PSMA ligands.

Case Report: 18F-PSMA-1007 PET/CT Avid Solitary Penile Metastasis of Castration-Resistant Prostate Cancer With a PSA of 0.072 ng/ml

Penile metastasis of prostate cancer is rare, with a poor prognosis, and only a limited number of relevant cases have been reported so far. With the application of ¹⁸F-PSMA-1007 PET/CT, the biochemical recurrence of prostate cancer can be detected at an early stage for providing important evidence, facilitating clinical decision-making. Here, we have reported a case of solitary penile metastatic recurrence in the context of mild PSA progression (PSA: 0.072 ng/ml). This case highlights the preferable sensitivity of ¹⁸F-PSMA-1007 PET/CT imaging in prostate cancer.

Brachytherapy for oligometastatic prostate cancer to the penis

The origin of penile metastases is in 70% of cases from primary pelvic cancers (genitourinary and recto-sigmoid primary tumors). The prognosis is poor and it is often associated with synchronous bone metastases at the time of diagnosis. We present the case of a 61-year-old patient who developed a penile induration 7 years after radical prostatectomy followed by adjuvant external beam radiation therapy for high-risk prostatic adenocarcinoma. Biopsies confirmed the metastatic localization and a detailed assessment failed to find any further remote lesions. Faced with this penile oligometastatic prostate cancer, we proposed an ablative treatment based on interstitial multi-catheter high-dose rate brachytherapy. At the six-month follow-up, clinical examination and ⁶⁸Ga-PSMA-11-PET confirmed a complete response of the penile tumor without new lesion at a distance.

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.

Penile secondary lesions: a rare entity detected by PET/CT

While penile metastases are rare, PET/CT has facilitated their detection. We aimed to describe penile secondary lesions (PSL) identified by PET/CT. We reviewed 18F-FDG and Ga68-PSMA PET/CT records performed in a single center during May 2012-March 2020, for PSL. Of 16,774 18F-FDG and 1,963 Ga68-PSMA-PET scans, PSL were found in 24(0.13%) men with a mean age of 74. PSMA detected PSL in 12 with prostate cancer; FDG identified PSL in 4 with lymphoma, 3 with colorectal cancer, 2 with lung cancer, and one each with bladder cancer, pelvic sarcoma, and leukemia. Mean SUVmax of PSL was 7.9 ± 4.2 with focal uptake in 13(54%). Mean lesion size was 16.5 ± 6.8 mm; 8 at the penile root, 4 along the shaft, and 1 at the glans. CT detected loss of the penile texture in 15(63%). PSL were observed only during relapse or follow-up of disseminated disease. Among those with prostate cancer, PSA varied widely. Fifteen (62.5%) died, at a mean 13.3 ± 15.9 months following PSL demonstration, nine had non-prostate malignancies. PET/CT identified and characterized PSL in a fraction of cancer patients, most commonly those with prostate cancer. PSL universally surfaced in advanced disease, and signaled high mortality, especially in non-prostate cancers.