Testicular Metastasis from Recurrent Gastroesophageal Junction Adenocarcinoma: Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Findings

A 57-year-old male was diagnosed with HER-2-positive gastroesophageal junction (GEJ) adenocarcinoma (T3N1) 3 years ago. He received neoadjuvant chemotherapy followed by surgical resection. The histopathological examination of the resected specimen revealed a moderately differentiated tumor measuring 2.2 cm × 1.9 cm × 1.0 cm with negative tumor margins and negative regional lymph nodes. In addition, Barrett's mucosa with high-grade dysplasia in the adjacent mucosa was noted. An 8-month postsurgery follow-up ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) revealed an FDG avid celiac node and lesion involving the left lamina of fourth lumbar vertebra (L4) (maximum standardized uptake value [SUVmax] = 10.5). This was confirmed on biopsy to be metastatic from GEJ adenocarcinoma. The patient underwent multiple chemotherapies, and the subsequent PET/CT revealed further progression of L4 metastasis and new hypermetabolic lesions in the left (SUVmax = 9.2) and right testis (SUVmax = 4.7) [Figure 1]. The scrotal ultrasound (US) showed bilateral, multifocal, hypervascular, and hypoechoic lesions in the areas corresponding to FDG avid testicular lesions [Figure 2]. Laboratory tests revealed an elevated carcinoembryonic antigen. The patient was started on a new chemotherapy agent, but the follow-up PET/CT showed interval progression (left testis: SUVmax = 20.7; right testis: SUVmax = 17.2) [Figure 1]. Based on imaging findings showing unequivocal progression, the diagnosis of testicular metastasis was confirmed.

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Figure 1 Maximum intensity projection image (a) and axial fluorodeoxyglucose positron emission tomography/computed tomography images (b) demonstrating tracer uptake in the left (pink arrow) and right testicles (yellow arrow). Additional fluorodeoxyglucose avid L4 vertebral lesion (red arrow) can be noted on maximum intensity projection image (a). The follow-up positron emission tomography/computed tomography showing marked interval progression of testicular lesions as seen here on maximum intensity projection images (c) and axial fluorodeoxyglucose positron emission tomography/computed tomography images (d and e)

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Figure 2 Ultrasound showing multiple bilateral hypoechoic lesions (arrow) in the right (a and b) and left testis (c). On the left testis Doppler, (d) the lesion was demonstrated to be hypervascular

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Esophageal carcinoma is the sixth leading cause of cancer-related mortality worldwide.[12] Barrett's esophagus is presumed to be the precursor for esophageal and GEJ adenocarcinoma, which was also noted in this case. Metastatic testicular malignancy is very rare, with around 200 reported cases. It accounts for 0.02%–2.5% of total testicular malignancies with the most common primary sites being prostate, lung, and stomach.[3] Only two cases of testicular metastasis from esophageal carcinoma have been reported.[45] Testicular metastasis is usually associated with the presence of diffuse disease and is a bad prognostic indicator. The exact mechanism through which tumor cells spread to the testis is not known. However, several theories suggesting different routes have been postulated including hematogenous, lymphatic, transperitoneal seeding along a patent tunica vaginalis, direct extension through the retroperitoneum and retrograde extension through vas deferens.[46] To the best of our knowledge, the FDG PET/CT characteristics of testicular metastasis from esophageal carcinoma have not been described previously.

Secondary testicular tumor usually presents as a unilateral multinodular painless intrascrotal mass.[4] Due to lack of literature, there are no well-defined guidelines for the management of metastatic testicular mass. Therefore, management of each patient should be individualized based on clinical-pathologic-radiologic evaluation. US can help confirm the presence of testicular mass. Orchiectomy followed by histopathological examination can be helpful for the definitive diagnostic. However, in this case, the diagnosis was confirmed based on follow-up imaging findings.

Since testicular metastasis is usually associated with widespread disease, a PET/CT can be helpful as a surveillance modality in such patients. In addition, radiologists need to be aware of uncommon sites of metastasis in esophageal cancer such as testis for correct interpretation and patient management.