Computed Tomographic Features of Intra-Abdominal Testicular Torsion in Cryptorchid Dogs.

Intra-abdominal cryptorchidism and testicular neoplasia are risk factors for the development of intra-abdominal testicular torsion (IATT). Testicular torsion may be associated with complete or incomplete vascular occlusion, leading to ischemia and necrosis, and, therefore, IATT necessitates urgent orchidectomy. This case series describes the CT features of complete (5/6) and incomplete (1/6) IATT in six dogs with surgically and histopathologically confirmed diagnoses, including torsion of both neoplastic (4/6) and non-neoplastic (2/6) testes. Clinical signs included acute abdominal pain, a palpable abdominal mass, inappetence, and vomiting. Testicular neoplasia included Seminoma (2/4) and Sertoli cell tumor (2/4). Both cases of Sertoli cell tumor were associated with hyperestrogenism, one of which had metastasized to the ipsilateral medial iliac lymph node (1/2). Orchidectomy was curative in 5/6 dogs. CT features of IATT included a mid or caudal intra-abdominal, soft tissue attenuating mass with a "whirl sign" of the testicular vascular pedicle, pampiniform plexus, and/or gubernaculum (6/6); enlargement of the testis, pampiniform plexus and epididymis (6/6); and peritoneal effusion (6/6). Features observed only in complete IATT were interruption of testicular arterial contrast filling (4/5), absent testicular parenchymal contrast enhancement, and absent contrast filling of the pampiniform plexus (5/5). By comparison, contrast enhancement or filling of these structures was present only in the incomplete IATT case. IATT should be considered a differential diagnosis for acute abdominal pain and an intra-abdominal mass in cryptorchid dogs with the CT features reported in this limited series. It should also be recognized that IATT is often secondary to testicular neoplasia.