DOI: 10.1148/rg.256055069
RadioGraphics 2005;25:1629-1638
© RSNA, 2005
Imaging of Penile Neoplasms1
Ajay K. Singh, MD,
Anuradha Saokar, MD,
Peter F. Hahn, MD, PhD and
Mukesh G. Harisinghani, MD
1 From the Divisions of Emergency Radiology (A.K.S.) and Abdominal Imaging and Interventional Radiology (A.K.S., A.S., P.F.H., M.G.H.), Massachusetts General Hospital, White 270, 55 Fruit St, Boston, MA 02114. Presented as an education exhibit at the 2004 RSNA Annual Meeting. Received March 29, 2005; revision requested April 12 and received May 16; accepted May 17. All authors have no financial relationships to disclose.
Address correspondence to A.K.S. (e-mail: Pallaviajay{at}hotmail.com).
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Abstract
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The assessment of penile cancer on the basis of clinical findings alone can often result in inaccurate staging and suboptimal treatment. Imaging of primary penile cancer and metastatic lymphadenopathy can help optimize planning of both primary tumor resection and treatment for lymph node metastases. Magnetic resonance (MR) imaging is the most accurate imaging modality in the assessment of primary penile cancers, which usually manifest as solitary, ill-defined infiltrating tumors that are hypointense on both T1- and T2-weighted MR images. T2-weighted MR imaging allows delineation of the tumor margin and of any extension into the penile shaft. On gadolinium-enhanced T1-weighted images, the tumors enhance to a greater extent than do the corpora cavernosa. In addition, the recently introduced technique known as lymphotrophic nanoparticle–enhanced MR imaging can help identify metastatic lymph node disease. However, further studies will be needed to determine the role of this imaging technique in clinical practice. Computed tomography does not clearly depict the local extension of primary penile cancer; however, it is useful in assessing metastases and postoperative complications.
© RSNA, 2005
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LEARNING OBJECTIVES
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After reading this article and taking the test, the reader will be able to:- Describe the typical MR imaging appearance of primary and secondary penile cancer.
- Discuss the current status of imaging in the assessment of penile cancer.
- List the common histologic types of penile cancer and their imaging features.
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Introduction
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Penile cancer is a relatively rare neoplasm in the developed world. Although it accounts for 10%–20% of all malignancies in males in Asia, Africa, and South America, it has a prevalence of only 1% in Western countries (1,2). In the United States, penile cancer accounts for approximately 0.4% of all male malignancies (3). The main prognostic factors for carcinoma of the penis are the degree of invasion by the primary tumor and the status of the draining lymph nodes (4). In addition to helping predict length of survival, these two factors are crucial in making appropriate treatment decisions. Palpation of the primary tumor and the inguinal nodes has been the traditional approach for assessment of local invasion of the corpora and skin and evaluation for inguinal nodal metastases. Primary tumor staging by means of palpation can often result in understaging of the disease (5). Also, nodal assessment based on the palpation of inguinal lymph nodes can produce both false-positive and false-negative results (6). Although physical examination can reliably help predict primary tumor size and the extent of cavernosal infiltration with a high positive predictive value, magnetic resonance (MR) imaging remains the most sensitive method for making these determinations (7). For these reasons, imaging has a very important role in the management of penile cancer. It can complement the initial clinical evaluation and enhance the accuracy of preoperative staging. MR imaging depicts the penile anatomy in detail, including its relationship to surrounding structures. With the development of newer technologies like lymphotrophic nanoparticle–enhanced MR imaging for distinguishing benign from metastatic lymph nodes, it is possible to accurately image for meta-static disease.
When the diagnosis is made early (stage I or II), penile cancer is often curable. The curability of penile cancer decreases sharply for the more advanced stages of disease (stages III and IV). Therefore, it is important to accurately stage the primary disease and detect extension to local as well as distant lymph nodes. In particular, the accurate assessment of local or distant neoplastic disease in penile carcinoma patients is crucial in determining the proper surgical approach and predicting the length of survival.
In this article, we review the normal penile anatomy as well as MR imaging technique in the evaluation of the penis. We also discuss and illustrate penile cancer in terms of causes, pathologic considerations, location, staging and prognosis, imaging considerations (including manifestations at MR imaging and computed tomography [CT]), and treatment.
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Normal Anatomy
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The penile shaft is composed of three tubular structures: the paired corpora cavernosa, located in the dorsal aspect of the penis; and the single, ventral midline corpus spongiosum (Figs 1 , 2). The corpus spongiosum contains the urethra and extends anteriorly to form the glans penis. The corpora cavernosa and corpus spongiosum have intermediate signal intensity with T1-weighted MR imaging sequences and high signal intensity with T2-weighted sequences. The muscular walls of the urethra appear hypointense relative to the corpus spongiosum. Three layers of connective tissue cover the corpora of the penis. The innermost layer is the fibrous tunica albuginea, which surrounds the corpora cavernosa and corpus spongiosum and is thicker around the corpora cavernosa (8). Another fibrous layer, the Buck fascia, surrounds the corpora cavernosa and separates them from the corpus spongiosum. Both the tunica albuginea and the Buck fascia are hypointense with T1- and T2-weighted sequences. MR imaging cannot reliably help distinguish the tunica albuginea from the adjacent Buck fascia; they are depicted as a single thick rim that is hypointense relative to the erectile tissues. The contrast between the corpora and the tunica albuginea increases on T2-weighted images. External to the Buck fascia is a loose layer of subcutaneous connective tissue that appears hyperintense relative to the Buck fascia on T2-weighted images. The dartos fascia envelops this layer of subcutaneous connective tissue and separates it from the overlying skin. The dartos fascia is also hypointense with all pulse sequences.
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Figure 1a. Normal penile anatomy. (a) Drawing (axial view) illustrates the normal penile anatomy. 1 = corpora cavernosa, 2 = corpus spongiosum, 3 = tunica albuginea, 4 = cavernosal arteries, 5 = deep dorsal vein, 6 = superficial dorsal vein, 7 = Buck fascia, 8 = dartos tunica. (b) Axial T2-weighted MR image shows the two corpora cavernosa (straight arrows) and the ventral corpus spongiosum (curved arrow). The tunica albuginea (arrowhead) surrounds the corpora cavernosa. (c) Drawing (sagittal view) illustrates the normal penile anatomy. 1 = corpus cavernosum, 2 = corpus spongiosum, 3 = urethra, 4 = glans penis, 5 = tunica albuginea. (d) Sagittal MR image shows the corpus spongiosum (arrow) flaring posteriorly into bulbous spongiosum (arrowheads). (e) Axial T2-weighted MR image shows the base of the penis and the attachment of the posterior portion of the corpora cavernosa, known as the crura (arrowheads), to the pubic arch. (f) Sagittal contrast material–enhanced T1-weighted MR image shows the corpus cavernosum (arrow) and the corpus spongiosum (arrowhead).
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Figure 1b. Normal penile anatomy. (a) Drawing (axial view) illustrates the normal penile anatomy. 1 = corpora cavernosa, 2 = corpus spongiosum, 3 = tunica albuginea, 4 = cavernosal arteries, 5 = deep dorsal vein, 6 = superficial dorsal vein, 7 = Buck fascia, 8 = dartos tunica. (b) Axial T2-weighted MR image shows the two corpora cavernosa (straight arrows) and the ventral corpus spongiosum (curved arrow). The tunica albuginea (arrowhead) surrounds the corpora cavernosa. (c) Drawing (sagittal view) illustrates the normal penile anatomy. 1 = corpus cavernosum, 2 = corpus spongiosum, 3 = urethra, 4 = glans penis, 5 = tunica albuginea. (d) Sagittal MR image shows the corpus spongiosum (arrow) flaring posteriorly into bulbous spongiosum (arrowheads). (e) Axial T2-weighted MR image shows the base of the penis and the attachment of the posterior portion of the corpora cavernosa, known as the crura (arrowheads), to the pubic arch. (f) Sagittal contrast material–enhanced T1-weighted MR image shows the corpus cavernosum (arrow) and the corpus spongiosum (arrowhead).
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Figure 1c. Normal penile anatomy. (a) Drawing (axial view) illustrates the normal penile anatomy. 1 = corpora cavernosa, 2 = corpus spongiosum, 3 = tunica albuginea, 4 = cavernosal arteries, 5 = deep dorsal vein, 6 = superficial dorsal vein, 7 = Buck fascia, 8 = dartos tunica. (b) Axial T2-weighted MR image shows the two corpora cavernosa (straight arrows) and the ventral corpus spongiosum (curved arrow). The tunica albuginea (arrowhead) surrounds the corpora cavernosa. (c) Drawing (sagittal view) illustrates the normal penile anatomy. 1 = corpus cavernosum, 2 = corpus spongiosum, 3 = urethra, 4 = glans penis, 5 = tunica albuginea. (d) Sagittal MR image shows the corpus spongiosum (arrow) flaring posteriorly into bulbous spongiosum (arrowheads). (e) Axial T2-weighted MR image shows the base of the penis and the attachment of the posterior portion of the corpora cavernosa, known as the crura (arrowheads), to the pubic arch. (f) Sagittal contrast material–enhanced T1-weighted MR image shows the corpus cavernosum (arrow) and the corpus spongiosum (arrowhead).
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Figure 1d. Normal penile anatomy. (a) Drawing (axial view) illustrates the normal penile anatomy. 1 = corpora cavernosa, 2 = corpus spongiosum, 3 = tunica albuginea, 4 = cavernosal arteries, 5 = deep dorsal vein, 6 = superficial dorsal vein, 7 = Buck fascia, 8 = dartos tunica. (b) Axial T2-weighted MR image shows the two corpora cavernosa (straight arrows) and the ventral corpus spongiosum (curved arrow). The tunica albuginea (arrowhead) surrounds the corpora cavernosa. (c) Drawing (sagittal view) illustrates the normal penile anatomy. 1 = corpus cavernosum, 2 = corpus spongiosum, 3 = urethra, 4 = glans penis, 5 = tunica albuginea. (d) Sagittal MR image shows the corpus spongiosum (arrow) flaring posteriorly into bulbous spongiosum (arrowheads). (e) Axial T2-weighted MR image shows the base of the penis and the attachment of the posterior portion of the corpora cavernosa, known as the crura (arrowheads), to the pubic arch. (f) Sagittal contrast material–enhanced T1-weighted MR image shows the corpus cavernosum (arrow) and the corpus spongiosum (arrowhead).
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Figure 1e. Normal penile anatomy. (a) Drawing (axial view) illustrates the normal penile anatomy. 1 = corpora cavernosa, 2 = corpus spongiosum, 3 = tunica albuginea, 4 = cavernosal arteries, 5 = deep dorsal vein, 6 = superficial dorsal vein, 7 = Buck fascia, 8 = dartos tunica. (b) Axial T2-weighted MR image shows the two corpora cavernosa (straight arrows) and the ventral corpus spongiosum (curved arrow). The tunica albuginea (arrowhead) surrounds the corpora cavernosa. (c) Drawing (sagittal view) illustrates the normal penile anatomy. 1 = corpus cavernosum, 2 = corpus spongiosum, 3 = urethra, 4 = glans penis, 5 = tunica albuginea. (d) Sagittal MR image shows the corpus spongiosum (arrow) flaring posteriorly into bulbous spongiosum (arrowheads). (e) Axial T2-weighted MR image shows the base of the penis and the attachment of the posterior portion of the corpora cavernosa, known as the crura (arrowheads), to the pubic arch. (f) Sagittal contrast material–enhanced T1-weighted MR image shows the corpus cavernosum (arrow) and the corpus spongiosum (arrowhead).
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Figure 1f. Normal penile anatomy. (a) Drawing (axial view) illustrates the normal penile anatomy. 1 = corpora cavernosa, 2 = corpus spongiosum, 3 = tunica albuginea, 4 = cavernosal arteries, 5 = deep dorsal vein, 6 = superficial dorsal vein, 7 = Buck fascia, 8 = dartos tunica. (b) Axial T2-weighted MR image shows the two corpora cavernosa (straight arrows) and the ventral corpus spongiosum (curved arrow). The tunica albuginea (arrowhead) surrounds the corpora cavernosa. (c) Drawing (sagittal view) illustrates the normal penile anatomy. 1 = corpus cavernosum, 2 = corpus spongiosum, 3 = urethra, 4 = glans penis, 5 = tunica albuginea. (d) Sagittal MR image shows the corpus spongiosum (arrow) flaring posteriorly into bulbous spongiosum (arrowheads). (e) Axial T2-weighted MR image shows the base of the penis and the attachment of the posterior portion of the corpora cavernosa, known as the crura (arrowheads), to the pubic arch. (f) Sagittal contrast material–enhanced T1-weighted MR image shows the corpus cavernosum (arrow) and the corpus spongiosum (arrowhead).
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Figure 2. Drawing illustrates local staging of penile neoplasms: T1, invasion of subepithelial connective tissue; T2, invasion of one or more corpora; T3, invasion of urethra or prostate gland; T4, invasion of other adjacent structures; and Tis, carcinoma in situ.
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The corpus spongiosum and corpora cavernosa enhance with the administration of gadopentetate dimeglumine. The enhancement of the corpus spongiosum occurs almost immediately, whereas the cavernosal bodies enhance gradually in a centrifugal fashion. This pattern of enhancement is attributed to the central location of the cavernosal artery (9).
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MR Imaging Technique
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Appropriate patient positioning is essential in MR imaging of the penis. With the patient supine, a folded towel is placed between the patient’s legs beneath the scrotum to elevate the scrotum and penis. The penis is then dorsiflexed against the lower abdomen in the midline and taped in position to reduce the motion of the organ during the examination. A surface coil is placed on the penis to obtain optimal-quality, high-resolution images. The most important MR imaging sequences are the T2-weighted and gadolinium-enhanced T1-weighted sequences. If the entire pelvis needs to be evaluated, a phased-array pelvic or body coil is used.
A recent small study by Scardino et al (10) suggested that MR imaging of the erect penis after the injection of prostaglandin E1 into the corpora cavernosa has the potential to improve local staging. However, because of the risk of priapism in a minority of patients, this technique is not routinely used.
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Penile Cancer
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Causes
Penile cancer is seen in men in the 6th and 7th decades of life; less than one-quarter of patients are under 40 years of age (2,3). The most important etiologic factor in penile cancer is the presence of foreskin, which results in the accumulation of smegma. Therefore, the risk of this disease is three times higher in uncircumcised men than in circumcised men. Poor hygiene also contributes to the development of penile cancer through the accumulation of smegma and other irritants. The presence of phimosis has a strong association with penile cancer and is seen in 25% of penile cancer patients (2). Other risk factors include chronic inflammatory conditions (eg, balanoposthitis, lichen sclerosus et atrophicus), smoking, treatment with psoralen or ultraviolet A photo-chemotherapy, human papilloma virus 16, and human papilloma virus 18 (2).
Pathologic Considerations
Primary neoplasms of the penis can be classified into the following histologic types: squamous cell carcinoma, sarcoma, melanoma, basal cell carcinoma, and lymphoma (11,12). Squamous cell carcinoma accounts for more than 95% of all primary neoplasms of the penis (1,11). Sarcomas are uncommon penile neoplasms and include epithelioid sarcoma, Kaposi sarcoma, leiomyosarcoma, and rhabdomyosarcoma (2).
Secondary or metastatic tumors of the penis have also been reported; in approximately 70% of cases, the primary tumor is located in the urogenital tract (13). Metastases to the penis from other primary cancers involving the colon, rectum, stomach, bronchus, and thyroid gland have also been reported (14–17). Penile metastases should be suspected in patients with a known diagnosis of cancer who present with multiple palpable painless nodules or unexplained priapism.
Location
Squamous cell carcinoma of the penis is most commonly located in the glans penis (48% of cases). In decreasing order of frequency, other locations include the prepuce (21% of cases), glans penis and prepuce (9%), coronal sulcus (6%), and shaft (2%) (2). The spread of penile cancer usually occurs via lymphatic vessels, with the Buck fascia acting as a barrier to corporal invasion and hematogenous spread (17). The lymphatic spread of cancer from the penis differs with the location of the primary lesion (18). The lymphatic vessels of the skin of the penis and prepuce drain primarily into the superficial inguinal nodes. The lymphatic vessels of the glans penis drain into the deep inguinal and external iliac nodes, and those of the erectile tissue and penile urethra drain into the internal iliac nodes. Because there is communication between lymphatic vessels, bilateral lymphadenopathy may be seen with a unilateral tumor. Invariably, the lymphatic vessels of the penis first drain into the inguinal nodes before reaching the pelvic nodes (5,19,20).
Staging and Prognosis
Two staging systems are used for assessing a patient with penile carcinoma: the Jackson classification system (Table 1) and the TNM classification system (Table 2).
The presence and degree of lymph node involvement is the most important prognostic indicator. In a study of 201 patients by Ravi (21), the 5-year survival rate declined from 95% for patients without nodal disease to 81% for patients with one to three positive inguinal lymph nodes and to 50% for patients with four or more positive lymph nodes. None of the patients with pelvic nodal disease survived to 5 years (21).
The prevalence of nodal involvement is related to the stage of the primary lesion. Nodal disease occurs in 20% of T1 tumors and in 47%–66% of T2–T4 penile cancers (22). Other determinants of lymphatic spread are the histologic grade, the vertical growth of the tumor, and the presence of vascular or lymphatic invasion (2,23). Superficially spreading squamous cell carcinoma is associated with positive lymph node disease in 42% of cases, whereas 82% of tumors with a deeper vertical growth pattern have lymph node metastases (24). Verrucous carcinoma of the penis shows an aggressive local behavior with a high prevalence of urethral and corporal invasion (25). In patients with penile cancer, metastasis to the pelvic lymph nodes is uncommon in the absence of inguinal metastases.
Imaging Considerations
Imaging can complement clinical examination and can be used to evaluate the primary lesion for local invasion, assess the status of the regional lymph nodes, and look for evidence of distant metastases.
Imaging of the Primary Tumor.—
MR imaging is superior to CT in the evaluation of primary tumors due to its superior soft-tissue resolution, multiplanar capability, and excellent spatial resolution in the assessment of superficial structures.
In general, T2-weighted and gadolinium-enhanced T1-weighted MR imaging sequences are the most useful in defining the local extent of a penile neoplasm (Figs 3–5). The depth of tumor invasion and involvement of the tunica albuginea, corpora, or urethra can also be determined. Primary penile cancers are most often solitary, ill-defined infiltrating tumors that are hypointense relative to the corpora on both T1- and T2-weighted images. The tumors enhance on gadolinium-enhanced images, although to a lesser extent than the corpora cavernosa.
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Figure 3. Verrucous carcinoma of the penis. Sagittal T2-weighted MR image demonstrates a mass with heterogeneous signal intensity (arrowheads) involving the glans penis and the corpora cavernosa.
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Figure 4. Squamous cell carcinoma of the penis. Coronal T2-weighted MR image shows a mass with heterogeneous signal intensity (arrowhead) involving the corpora cavernosa. Hydrocele is seen incidentally.
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Figure 5a. Adenoid cystic carcinoma arising from the Cowper gland. Coronal T2-weighted (a) and gadolinium-enhanced T1-weighted (b) MR images show a mass (arrow) centered at the bulbous urethra and infiltrating the left obturator internus muscle.
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Figure 5b. Adenoid cystic carcinoma arising from the Cowper gland. Coronal T2-weighted (a) and gadolinium-enhanced T1-weighted (b) MR images show a mass (arrow) centered at the bulbous urethra and infiltrating the left obturator internus muscle.
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Penile metastases typically manifest as multiple discrete masses in the corpora cavernosa and corpus spongiosum (Fig 6). These masses are seen as low-signal-intensity areas within the corporal bodies relative to normal corporal tissue with both T1- and T2-weighted sequences (13). The primary neoplasm is often located in the urogenital tract and can also be included in the field of view.
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Figure 6. Penile metastases from a prostatic primary neoplasm. Sagittal contrast-enhanced T1-weighted MR image shows extensive multiple low-signal-intensity lesions (circled) involving the corpora cavernosa and the corpus spongiosum.
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Imaging of Lymph Nodes.—
The determination of lymph node involvement by cancer is of paramount importance in planning treatment strategies (26). An essential problem in treating patients with penile cancer has been the unreliability of clinical methods and of conventional imaging methods for detecting lymph node metastases. Approximately 30%–60% of patients with squamous cell carcinoma have palpable inguinal lymph nodes at the time of initial diagnosis (6). In about one-half of these patients, the enlarged nodes harbor metastatic disease; in the other one-half, the palpable lymph nodes are reactive (27). Several studies have shown the sensitivity of clinical staging of the nodes to be 40%–60% with a false-negative rate of around 10%–20% (28,29).
The capacity of CT and MR imaging to help detect lymph node metastases is limited because the diagnosis is based on lymph node size. As a result, occult metastases in normal-sized lymph nodes will go undetected, whereas enlarged nodes secondary to infection or inflammation will be labeled as malignant. The advantage of CT and MR imaging over clinical examination is that they can help detect lymph nodes in the pelvis and retroperitoneum that are inaccessible at physical examination.
Prophylactic inguinal lymphadenectomy has been recommended by some investigators for overcoming this problem and has been shown to improve long-term survival rates (29–31). However, subjecting all patients to this procedure would result in overtreatment in 60%–75% of cases (32). The main drawback of this approach is that inguinal lymphadenectomy is associated with a 30%–50% rate of major morbidity, including severe lymphedema and skin flap necrosis and a 1%–3% mortality rate (22,32–35). Hence, an effort should be made to identify patients with lymph node metastases who will benefit from the procedure, thereby achieving a suitable balance between therapeutic benefit and the morbidity of lymphadenectomy. In the past, the treatment algorithm for penile cancer was based solely on clinical examination findings, and preoperative imaging was not routinely performed because CT and MR imaging were not reliable in assessing metastatic lymphadenopathy.
The recently introduced technique of lymphotrophic nanoparticle–enhanced MR imaging allows the characterization of lymph nodes in patients with various cancers (36–39). MR imaging is performed with ferumoxtran-10, which consists of ultrasmall superparamagnetic iron oxide particles. Normal lymph nodes contain macrophages, which engulf the iron oxide nanoparticles. Malignant lymph nodes lack the phagocytic cells needed to take up the nanoparticles (40). Therefore, nonmetastatic lymph nodes show homogeneous uptake of ferumoxtran-10 and appear dark due to shortening of T2 and T2*, whereas malignant lymph nodes do not take up the contrast material and appear bright (Fig 7). Because the interpretation is based on nodal function rather than structure, it is possible to detect subcentimeter metastases in normal-sized nodes and to accurately characterize enlarged reactive lymph nodes.
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Figure 7a. Metastatic left groin lymphadenopathy from penile carcinoma. (a) T2*-weighted MR image obtained before the administration of ultrasmall superparamagnetic iron oxide particles shows an enlarged lymph node in the left groin (arrow). (b) On a T2*-weighted MR image obtained after administration of the iron oxide particles, the enlarged lymph node (arrow) appears bright due to lack of particle uptake, a finding that indicates replacement of the lymph node parenchyma by metastatic tissue. A smaller left inguinal lymph node (arrowhead) shows normal particle uptake and is hypointense owing to susceptibility effect.
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Figure 7b. Metastatic left groin lymphadenopathy from penile carcinoma. (a) T2*-weighted MR image obtained before the administration of ultrasmall superparamagnetic iron oxide particles shows an enlarged lymph node in the left groin (arrow). (b) On a T2*-weighted MR image obtained after administration of the iron oxide particles, the enlarged lymph node (arrow) appears bright due to lack of particle uptake, a finding that indicates replacement of the lymph node parenchyma by metastatic tissue. A smaller left inguinal lymph node (arrowhead) shows normal particle uptake and is hypointense owing to susceptibility effect.
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Imaging of Distant Metastases.—
Distant metastasis is uncommon in patients who present with penile cancer (<3% of cases) (41). Generally, distant metastases occur late in the course of the disease and are associated with a dismal prognosis. The most common sites of metastases are the lung, liver, and retroperitoneum.
Although CT plays only a limited role in primary tumor evaluation, its use is favored in the evaluation of distant metastases (Figs 8, 9). CT can be used to postoperatively assess a penile implant for primary tumor and can provide guidance in the drainage of postoperative abscess.
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Figure 9. Lymph node metastases from penile carcinoma. Contrast-enhanced CT scan shows bilateral metastatic lymph node involvement (arrowheads) in the form of inguinal and right common iliac lymphadenopathy.
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Treatment
The treatment of penile cancer varies depending on the site and extent of the primary cancer and the presence of metastatic inguinal lymphadenopathy. Circumcision alone may cure patients with small tumors of the distal prepuce, whereas tumors of the glans penis and distal shaft require partial penectomy, including a 2-cm tumor-free margin. Bulky tumors of the proximal penis (Fig 4) are treated with total penectomy and perineal urethrostomy. Inguinal lymphadenectomy can be performed at the time of the penile surgery or later. The current approach for dealing with palpable inguinal lymph nodes includes reevaluation after 4–6 weeks of antibiotic therapy. This approach is based on the principle that reactive lymphadenopathy will resolve following antibiotic treatment, whereas neoplastic lymphadenopathy will persist. The continued presence of lymph nodes in the inguinal region is treated with bilateral inguinal lymphadenectomy.
Radiation therapy with external beam irradiation and brachytherapy has yielded local control rates similar to those for surgical resection (2). Radiation therapy and laser therapy are the best conservative therapeutic options for localized disease. Treatment for penile metastases is generally palliative (42).
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Conclusions
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The assessment of a primary penile tumor and inguinal lymph nodes by means of palpation alone can often result in inaccurate staging. The high-resolution images of the penis obtained with MR imaging allow accurate assessment of local tumor invasion. In addition, the important clinical question of whether metastatic lymph node disease exists can potentially be answered with use of the recently introduced technique known as lymphotrophic nanoparticle–enhanced MR imaging. However, the role of this imaging technique has not yet been established, and further studies will be needed to determine its role in clinical practice.
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Abstract
LEARNING OBJECTIVES
