WBR0939

Author	PageAuthor::William J Gibson (Reviewed by Serge Korjian)
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Anatomy
Sub Category	SubCategory::Genitourinary
Prompt	[[Prompt::A 25-year-old man presents to his primary care physician after he noticed an irregular hard lump in his right testicle. Serum placental alkaline phosphatase and lactate dehydrogenase are elevated and testicular ultrasound demonstrates a hypoechogenic homogeneous intratesticular mass. Which of the following sites would be the most likely first step in metastatic spread of this tumor?]]
Answer A	AnswerA::Internal iliac lymph nodes
Answer A Explanation	AnswerAExp::The internal iliac lymph nodes drain the rectum above the pectinate line.
Answer B	AnswerB::Superficial inguinal lymph nodes
Answer B Explanation	AnswerBExp::From below the pectinate line, the rectum is drained by the superficial inguinal lymph node.
Answer C	AnswerC::Mediastinal lymph nodes
Answer C Explanation	[[AnswerCExp::The mediastinal lymph nodes lie in the center of the chest, particularly along the trachea. The mediastinal lymph nodes give rise to the lymphatic ducts, which drain the lymph to the subclavian vein. While seminomas can present as primary tumors in the mediastinum, in this case we know that the primary is in the testes. Thus, we need to only assess the lymphatic drainage of the testes (para-aortic).]]
Answer D	AnswerD::Mesenteric lymph nodes
Answer D Explanation	[[AnswerDExp::The mesenteric lymph nodes drain the gut. The superior mesenteric lymph nodes drain all parts of the gut proximal to the sigmoid colon. The inferior mesenteric lymph nodes drain lymph from the sigmoid colon to the rectum (above the pectinate line).]]
Answer E	AnswerE::Para-aortic lymph nodes
Answer E Explanation	AnswerEExp::The para-aortic lymph nodes drain the testes and the lower gastrointestinal tract.
Right Answer	RightAnswer::E
Explanation	[[Explanation::The patient in this vignette has developed a seminoma, the most common adult germ cell tumor of the testes that mainly affects males between the ages of 15 and 35. These tumors are extremely sensitive to chemotherapy and radiation. Seminomas are associated with an excellent prognosis (5-year survival rate ~90%). Histologically, these tumors are known for containing abundant clear to pale pink cytoplasm with prominent nuclei. This combination of features, creates a “fried-egg” appearance. Because seminomas spread via lymphatic vessels, it is important to recognize the lymphatic drainage of the testicle. Due to the para-aortic embryologic origin of the Wolffian duct, the testes descend from the aorta. The vascular and lymphatic supply of the testes, is therefore tethered to this region. Thus, the testes are drained by the para-aortic lymph nodes. The para-aortic lymph nodes are the first site of seminoma metastasis, and a significant proportion of patients present with large retroperitoneal lymph nodes. Retroperitoneal lymph node dissection (RPLND) is an important therapeutic option with a high cure rate in patients with stage IA seminomas that have reached the para-aortic lymph nodes. Educational Objective: Testicular cancer will spread via lymphatics to the para-aortic lymph nodes. References: Chung PW, Bayley AJ, Sweet J, et al. Spermatocytic seminoma: a review. Eur Urol. 2004;45(4):495-8. Woodward PJ, Sohaey R, O'donoghue MJ, Green DE. From the archives of the AFIP: tumors and tumorlike lesions of the testis: radiologic-pathologic correlation. Radiographics. 2002;22(1):189-216.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Testicle, WBRKeyword::Testicular, WBRKeyword::Cancer, WBRKeyword::Lymph node, WBRKeyword::Lymph, WBRKeyword::Metastasis
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::