Metastatic duodenal germ cell tumor diagnosed with endoscopic ultrasound

Testicular tumors are the most common solid tumors reported in young males aged 15 – 35 years [1] [2]. These tumors frequently metastasize to retroperitoneal lymph nodes, but only 5 % of these tumors seed the gastrointestinal (GI) tract [3] [4], with the duodenum being the least common site (1.4 %) [4]. Local extension from the retroperitoneal lymph node into the GI tract is the common method of spread.

We report on a 44-year-old man with symptoms of gastric outlet obstruction. Computed tomography (CT) of the abdomen showed a bilobed retroperitoneal mass of 7 × 5 cm compressing the duodenum, suspicious for duplication cyst ([Fig. 1a, b]). Esophagogastroduodenoscopy showed a subepithelial near-obstructive mass in the second portion of the duodenum, which appeared cystic on palpation with closed forceps ([Fig. 1 c]). Endoscopic ultrasound (EUS) showed a 7 × 5.4 cm solid cystic mass ([Fig. 1 d]). Fine-needle biopsy (FNB) with a 22-gauge needle ([Fig. 1 e]) revealed poorly differentiated epithelioid carcinoma, with unknown primary. Given the patient’s age, testicular tumor was a highly likely differential diagnosis.

Fig. 1 Evaluation and diagnosis of a retroperitoneal mass. a Coronal computed tomography (CT) of the abdomen showed a retroperitoneal mass (arrow). b Transverse CT of the abdomen showed the same mass (arrow). c Upper endoscopy showed a subepithelial near-obstructive mass (arrow) in the second portion of the duodenum. d Endoscopic ultrasound showed a 7 × 5.4 cm solid cystic duodenal mass. e Fine-needle biopsy of the duodenal mass was performed. f Histology of the resected duodenal mass showed the presence of cartilage, consistent with mixed germ cell tumor.

Video 1 A duodenal mass was evaluated by endoscopic ultrasound. Upon biopsy, the mass was shown to be a metastatic germ cell tumor from the testis.

The patient underwent pancreas-sparing duodenal resection. Histology showed a mixed germ cell tumor with unusual presence of cartilage ([Fig. 1 f]). Ultrasound of the testes showed a 1.7 cm right testicular mass, which was resected, and histology was consistent with mixed germ cell tumor. Staging revealed bony metastasis. The patient is currently undergoing chemotherapy.

This case highlights a testicular mixed germ cell tumor with metastasis to the duodenum, which is rare (1.4 %). In addition, hematogenous spread without the local involvement of the lymph nodes was noted, which is also a rare phenomenon. EUS-FNB confirmed a previously unsuspected malignancy, prompting a search for the primary and subsequent surgical management.

In young males with upper gastrointestinal tumors, metastasis from a testicular mass should always be considered. EUS-FNB can provide valuable information.

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Competing interests

None

• References

• 1 Konheim JA, Israel JA, Delacroix SE. Klinefelter syndrome with poor risk extragonadal germ cell tumor. Urol Case Rep 2016; 10: 1-3
• 2 Fu S, Avezbakiyev B, Zhi W. et al. Germ cell cancer presenting as gastrointestinal bleeding and developing brain metastases: case report and review of the literature. Future Oncol 2012; 8: 1487-1493
• 3 Morinaga M, Osada T, Kon K. et al. Metastatic seminoma in the duodenum: diagnosis with endoscopy followed by successful treatment. Intern Med 2014; 53: 2777-2781
• 4 Bain AJ, Owens DJ, Savides TJ. Image of the month. Upper gastrointestinal bleeding caused by metastatic testicular choriocarcinoma. Clin Gastroenterol Hepatol 2009; 8: A22