The most frequent malignant nodules are metastatic melanomas. Metastases from lymphoma and lung, breast, ovary, and colon cancer are less common (Figure 17 ). 最常见的恶性结节是转移性黑素瘤，来自淋巴瘤和肺、乳腺、卵巢和结肠癌的转移不常见（图17）。
Apart from hernias, other lesions may present as small, palpable masses in the inguinal area. 在腹股沟区，除了疝，其他病变可表现为小的、可触及的肿物。
...Undescended Testis 睾丸未降（隐睾） Testicular descent can get arrested at any point from the renal hilum to the external inguinal ring. Of all the undescended testes, 90% to 95% are low and in the inguinal canal. Sonography is very useful in detection of undescended testes. The undescended testis is usually small. It is ovoid and reveals a homogeneous, hypoechoic structure. The presence of an echogenic hilum distinguishes a lymph node from a testis (Figure 18 ).