Multimodality imaging of penile cancer: what radiologists need to know

MR imaging of the penis: What a radiologist needs to know!

Magnetic resonance imaging (MRI) plays an important role in imaging of penile pathologies due to its excellent soft tissue resolution and multiplanar imaging capabilities. This imaging review describes the MRI protocols and anatomical considerations in penile pathologies. MRI not only serves as a complementary tool to ultrasound in evaluation of trauma, infections, inflammatory diseases, and malignancies, but is also used as the definitive imaging modality for evaluation of penile prosthesis and complex cases.

MR imaging of penile pathology and prostheses

Penile MRI is a vital yet underutilized diagnostic tool that provides detailed information crucial for managing various penile pathologies. Due to its infrequent use, many radiology trainees lack confidence in interpreting these exams. This article reviews the anatomy, key technical considerations, and interpretive pearls for penile trauma, Peyronie's disease, priapism, penile neoplasms, prosthesis evaluation, and a few miscellaneous conditions. Through illustrative case examples, this review aims to enhance the understanding and proficiency of radiologists in performing and interpreting penile MRI in these clinical scenarios.

Novel erectile analyses revealed augmentable penile Lyve-1, the lymphatic marker, expression

Purpose

The pathophysiology of penis extends to erectile dysfunction (ED) to conditions including sexually transmitted diseases (STDs) and cancer. To date, there has been little research evaluating vascular drainage from the penis. We aimed to evaluate penile blood flow in vivo and analyze its possible relationship with the lymphatic maker.

Materials and Methods

We established an in vivo system designed to assess the dynamic blood outflow from the corpus cavernosum (CC) by dye injection. To analyze lymphatic characteristics in the CC, the expression of Lyve-1, the key lymphatic endothelium marker, was examined by the in vitro system and lipopolysaccharide (LPS) injection to mimic the inflammatory conditions.

Results

A novel cavernography methods enable high-resolution morphological and functional blood drainage analysis. The expression of Lyve-1 was detected along the sinusoids. Furthermore, its prominent expression was also observed after penile LPS injection and in the erectile condition.

Conclusions

The current in vivo system will potentially contribute to the assessment of penile pathology from a novel viewpoint. In addition, current analyses revealed inducible Lyve-1 expression for LPS injection and the erection state, which requires further analyses on penile lymphatic system.

Malignant Neoplasms of the Penis with Radiologic and Pathologic Correlation

Penile malignancy is the third most common male-specific genitourinary malignancy, with squamous cell carcinoma representing the most common histologic type. Squamous cell carcinoma is an epithelial malignancy, frequently developing from the mucosal surfaces of the foreskin, glans, and coronal sulcus and manifesting as a distal infiltrative or ulcerated mass. This typically occurs in men from the 6th to 8th decades of life, and risk factors include human papillomavirus, phimosis, presence of foreskin and poor hygiene, chronic inflammatory conditions such as lichen sclerosus, trauma, and smoking. Primary urethral malignancies including urothelial carcinoma and adenocarcinoma can occur but may lack this distal predilection. Sarcoma, melanoma, leukemia or lymphoma, and metastatic disease are less common sources of penile malignancy. Because of the sensitive nature of penile malignancies, there may be delays in seeking care and in subsequent diagnosis. Recently, the staging guidelines for penile cancer have been updated concurrently with a shift toward more penile-preserving therapies, which have led to a larger role of imaging in diagnosis, staging, and treatment planning for penile malignancies. A variety of imaging modalities may play a role in the identification and staging of penile malignancy, including an increased use of MRI for local staging of tumors, CT and PET/CT for identification of nodal and distant disease, and US for image-guided biopsy. The authors discuss an imaging approach to a spectrum of penile malignancies, with an emphasis on radiologic and pathologic correlation and how knowledge of normal tissue types and anatomic structures can aid in the diagnosis and staging of these tumors. ^©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Current trends in penile cancer survivorship amongst remote patients and Aboriginal people in Western Australia

BACKGROUND

Penile cancer is a rare urological malignancy, accounting for less than 1% of all cancers in males. Given its rarity, few studies exist reporting survival outcomes. The primary objective of this project was to review the mortality of patients diagnosed with penile cancer in Western Australia between 1992 and 2017 and to determine if Aboriginal and Torres Strait Islander people and patients in rural and remote regions experience discrepancies in survival outcomes.

METHODS

All cases of penile cancer recorded within the Western Australia Cancer Registry between 1992 and 2017 were reviewed. Analysis was performed using chi-squared test of association, binomial logistic regression and survival analysis was conducted using Kaplan Meier and Cox Regression analysis.

RESULTS

One hundred eighty-six cases of penile cancer were identified; 62 patients (33%) were from regional or remote locations and nine patients (4.8%) were Aboriginal. 13 of the regional or remote patients and 5 of the Aboriginal patients died from penile cancer. Patients who were Aboriginal (HR 6.512, CI 2.123-19.968; P = 0.001) or from regional or remote Western Australia (HR 2.382, CI 1.050-5.401; P = 0.038) were at an increased risk of penile cancer-specific mortality.

CONCLUSIONS

Aboriginal people with penile cancer and men from regional and remote Western Australia experience worse penile cancer-specific survival outcomes.

Imaging for the Initial Staging and Post-Treatment Surveillance of Penile Squamous Cell Carcinoma

Although relatively rare in the United States, penile squamous cell carcinoma is encountered worldwide at a higher rate. Initial diagnosis is often made on clinical exam, as almost all of these lesions are externally visible and amenable to biopsy. In distinction to other types of malignancies, penile cancer relies heavily on clinical nodal staging of the inguinal lymph node chains. As with all cancers, imaging plays a role in the initial staging, restaging, and surveillance of these patients. The aim of this manuscript is to highlight the applications, advantages, and limitations of different imaging modalities in the evaluation of penile cancer, including ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography.

Diagnostic Performance of Magnetic Resonance Imaging for Preoperative Local Staging of Penile Cancer: A Systematic Review and Meta-Analysis

Invasion of the tunica albuginea (TA) and/or urethra are key factors in determining the feasibility of organ-preserving surgery in penile cancer (PC). Magnetic resonance imaging (MRI) appeared to be a promising technique for preoperative local staging. We performed a systematic review (SR) and pooled meta-analysis to investigate the diagnostic performance of MRI in preoperative local staging of primary PC. An SR up to May 2021 was performed according to the PRISMA statement. The diagnostic performance of MRI was evaluated according to TA invasion, urethra invasion, and pT-stage ≥ 2. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) from eligible studies were pooled and summary receiver operating characteristic (SROC) curves were constructed. Overall, seven qualified studies were deemed suitable. Diagnostic performance of MRI showed an accuracy of 0.89 for TA invasion (sensitivity 0.78, PPV 0.79, specificity 0.91, and NPV 0.90); an accuracy of 0.88 for urethra invasion (sensitivity 0.65, PPV 0.46, specificity 0.86, and NPV 0.93); an accuracy of 0.90 for pT ≥ 2 (sensitivity 0.86, PPV 0.84, specificity 0.70, and NPV 0.73).Currently available evidence indicates that MRI might be a one-stop shop for local staging of primary PC and play a central role with regard to conservative surgical management.

MRI of the penis

This article reviews the anatomy and magnetic resonance imaging (MRI) appearance of the penis. The recommended technique for MRI of the penis is outlined, with discussion of the benefits and drawbacks to imaging the penis after artificial erection. Common penile pathologies are reviewed, with a summary of their clinical features, MRI appearance, and treatment. The ability to demonstrate the erectile bodies and vasculature helps to evaluate vascular pathologies such as priapism, Mondor disease, and cavernosal thrombosis. MRI is also a useful tool to assess for traumatic abnormalities of the penis, with the depiction of soft tissue anatomy and fascial layers allowing for evaluation of penile fracture and penile contusion. Malignant disease of the penis is also reviewed, including squamous cell carcinoma, urethral carcinoma, metastases, and rare neoplasms. Staging of these neoplasms is addressed, with discussion of how MRI can be used to assess the extent of tumor involvement. MRI also clearly demonstrates the tunica albuginea, which allows for evaluation of Peyronie's disease.

Applications of PET/MR Imaging in Urogynecologic and Genitourinary Cancers

Positron emission tomograph (PET)-magnetic resonance (MR) is a new modality combining PET and MR. In gynecologic cancers it can be used for staging of cervical and endometrial cancer, planning of radiation therapy in cervical cancer, assessing response to chemotherapy in ovarian cancer, and detection of recurrence in most gynecologic cancers. It is being explored for prostate cancer and other genitourinary cancers, but is still in experimental stages.

Use of dual-phase contrast computed tomography for evaluation of the normal canine male genital tract

OBJECTIVES

To evaluate the use of dual-phase contrast-enhanced computed tomography for the depiction of the features of the male genital tract, highlighting differences between entire and neutered dogs.

METHODS

Computed tomography exams of 23 entire and 23 neutered male dogs with no history of urogenital disease were included in this retrospective study, with exams acquired pre-, 30 and 98·9 ±27·4 seconds after intravenous contrast administration. The genital structures were subjectively evaluated for visibility, contrast enhancement and enhancement pattern and differences between entire and neutered dogs were described. Objective measurements of attenuation and size of the prostatic tissue were acquired.

RESULTS

The root, body and glans of the penis could be evaluated in all dogs and appeared larger in entire dogs, though objective measurements could not be reliably made because these structures are small and curved. There was contrast enhancement of the cavernous structures, most reliably in the bulb and corpus spongiosum and most frequently in entire dogs in the delayed post-contrast phase. In entire dogs, the small testicular vessels most commonly had a vermiform shape in the early post-contrast phase, and a homogeneous appearance in the delayed phase. Sternal recumbency with the coxofemoral joints extended improved visibility of the genital structures.

CLINICAL SIGNIFICANCE

Dual-phase contrast-enhanced computed tomography is useful for depiction of the structures of the male genital tract, with the early phase especially highlighting the vascular and the delayed phase the cavernous structures.