POSITRON EMISSION TOMOGRAPHY DETECTION OF METASTATIC PENILE SQUAMOUS CELL CARCINOMA

0022-5347/01/1655-1633/0 THE JOURNAL OF UROLOGY® Copyright © 2001 by AMERICAN UROLOGICAL ASSOCIATION, INC.®

Vol. 165, 1633–1634, May 2001 Printed in U.S.A.

POSITRON EMISSION TOMOGRAPHY DETECTION OF METASTATIC PENILE SQUAMOUS CELL CARCINOMA GREGORY C. RAVIZZINI, MATTHEW WAGNER

AND

SALVADOR BORGES-NETO

From the Department of Radiology, Division of Nuclear Medicine, Duke University Medical Center, Durham, North Carolina KEY WORDS: carcinoma, squamous cell; penis; tomography, emission, computed; neoplasm metastasis

Squamous cell carcinoma of the penis is a rare malignancy in the United States and most industrialized countries. We report a case of recurrent metastatic penile squamous cell carcinoma detected by fluorine-18 (F-18) fluorodeoxyglucose positron emission tomography in a patient previously submitted to Mohs’ micrographic procedure and partial penectomy. CASE REPORT

A 58-year-old white man presented elsewhere with small white lesions on the glans of the penis in 1992. History included circumcision at age 16 years and multiple sequential rigid dilations for urethral stricture. Balanitis xerotica obliterans was diagnosed and treatment was local. The area became sore 5 years later and a biopsy revealed squamous cell carcinoma. The patient underwent Mohs’ procedure and was disease-free for the next 15 months when a recurrent lesion, just ventral to the meatus, was positive for squamous cell carcinoma. No palpable inguinal adenopathy was identified and a chest x-ray was negative for metastatic disease. The patient was referred to us and we recommended partial penectomy. In 1998 he underwent a wide wedge resection of the glans penis, meatus and distal urethra with plastic reconstruction of the distal penile shaft to accommodate a new meatus. Pathological examination confirmed invasive, well differentiated, keratinizing squamous cell carcinoma. All surgical margins were free of tumor. A firm mass in the left groin was palpated 2 years later. Computerized tomography (CT) of the pelvis identified a 3.5 ⫻ 2.5 cm. heterogeneous left inguinal mass consistent with nodal spread of penile carcinoma. No intravenous contrast material was given due to iodine allergy. Left superficial and deep inguinal lymph node dissection revealed metastatic keratinizing squamous cell carcinoma in 2 of 12 superficial lymph nodes. The largest positive node was 3 cm. and showed extracapsular invasion. All resected deep nodes were negative. The postoperative course was complicated by an increased drainage from the Jackson-Pratt drain, increased wound swelling and wound separation requiring daily packing and Accepted for publication December 21, 2000.

home nursing care. The patient noticed a small single nodule on the left anterior upper thigh 2 months after discharge from the hospital. Abdominal and pelvic CT without intravenous contrast material revealed multiple surgical clips and ill defined soft tissue at the left groin surgical site (fig. 1, A). Inferiorly in the left groin, there was a 4.5 ⫻ 4.5 cm. fluid attenuation lesion (fig. 1, B). It was difficult to discern between recurrent disease versus postoperative changes. CT of the chest showed multiple bilateral pulmonary nodules suspicious for metastatic disease. It is noteworthy that no hilar adenopathy was visualized. Whole body positron emission tomography after the intravenous injection of 11.39 mCi. F-18 fluorodeoxyglucose demonstrated multiple foci of increased fluorodeoxyglucose activity in the left groin, left upper thigh, left iliac chain and right groin (fig. 2). One of the abnormal areas of fluorodeoxyglucose activity in the left groin had central decreased uptake, which corresponded to the fluid collection on CT (fig. 2). In addition, there were punctuate foci of abnormal increased fluorodeoxyglucose uptake in the chest. A single focus was seen in the left upper lobe, which corresponded to a nodule on CT. Foci of increased activity were noted in both hila suspicious for metastatic disease, although no lymphadenopathy was visualized on CT. DISCUSSION

Penile cancer is an uncommon entity in the developed world.1 In 1999 it accounted for less than 0.5% of all newly diagnosed male cancers in the United States.1 In some geographic locations where infantile circumcision is not routinely performed and genital hygiene is inadequate, penile cancer represents a major public health problem.2 Squamous cell carcinoma is by far the most common histological type of invasive penile cancer comprising more than 97% of all cases. The management of penile squamous cell carcinoma often presents a challenging clinical dilemma. While organ sparing surgery is the most desirable procedure, it is not always feasible. The recommendation for partial or total penectomy for invasive penile carcinoma (stage 2 or higher) usually carries a strong emotional repercussion. Furthermore, the optimal management of inguinal lymph nodes is still contro-

FIG. 1. Axial image from pelvic CT. A, ill defined soft tissue medial to surgical clips at postoperative site. B, 4.5 ⫻ 4.5 cm. fluid attenuation lesion medial to surgical clips. 1633

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conventional radiological methods, such as CT or magnetic resonance imaging. Positron emission tomography with the radioactive tracer F-18 fluorodeoxyglucose has been increasingly used in oncology imaging.3 The fundamentals of positron emission tomography rely not solely in anatomic identification but mainly in physiological characterization of malignant tissues. Most cancers exhibit increased rates of glucose use because malignant cells have a higher rate of aerobic and anaerobic glycolysis, and display accelerated glucose membrane transport. Similar to glucose, the analog fluorodeoxyglucose tagged with the radioactive isotope fluorine-18 is transported into glucose avid cells and can be used to obtain functional images. Positron emission tomography has been used in the study of a wide variety of neoplasms, such as lymphoma, melanoma, lung and colorectal cancer. To our knowledge, positron emission tomography detection of metastatic penile squamous cell carcinoma has never been reported in the literature. Consequently, more research is needed to prove the real usefulness of positron emission tomography in the detection and management of this entity. FIG. 2. Coronal F-18 fluorodeoxyglucose images depict large areas of abnormally increased fluorodeoxyglucose uptake in the left hemipelvis, groin and scrotum. Inferior lesion has central area of low fluorodeoxyglucose uptake, which corresponds to fluid attenuation lesion seen on CT and likely represents necrosis.

versial. Patients with penile carcinoma frequently have enlarged inguinal lymph nodes, mainly due to inflammation, and exclusion of metastatic disease is sometimes difficult by

REFERENCES

1. Landis, S. H., Murray, T., Bolden, S. et al: Cancer statistics, 1999. CA Cancer J Clin, 49: 8, 1999 2. Persky, L.: Epidemiology of cancer of the penis. Recent Results Cancer Res, 60: 97, 1977 3. Delbeke, D.: Oncological applications of FDG PET imaging: brain tumors, colorectal cancer, lymphoma and melanoma. J Nucl Med, 40: 591, 1999