Hemangioma
Adenoma
Focal nodular hyperplasia
Focal fatty infiltration
Hepatocellular carcinoma
Lymphoma
Sarcoma
Leiomyoma
Teratoma
Metastatic tumor
Abscess
Benign cysts
Echinococcal cyst

Pancreaticobiliary masses
Pancreatic adenocarcinoma
Lymphoma
Neuroendocrine tumors
Pseudocysts
Abscess
Mucinous and serous cystadenoma
Cystadenocarcinoma
Intraductal papillary mucinous tumors
Bile duct adenoma
Choledochocele
Cholangiocarcinoma
Gallbladder carcinoma
Granular cell tumor

Gastrointestinal masses
Adenocarcinoma
Adenoma
Lymphoma
Hyperplastic polyps
Hamartoma
Leiomyoma
Leiomyosarcoma
Leioblastoma
Kaposi sarcoma
Carcinoid
Colitis cystica profunda
Lipoma
Liposarcoma
Angioma
Neuroma
Schwannoma
Inflammatory mass (Crohn’s disease, appendicitis)
Abscess

Miscellaneous masses
Renal cell carcinoma
Renal cyst
Transitional cell carcinoma of the renal pelvis
Renal lymphoma
Mesenteric cyst
Cystic teratoma
Mesothelioma
Hematoma
Abdominal aortic aneurysm
Ovarian carcinoma
Ovarian cyst
Uterine fibroma
Uterine carcinoma
Tubo-ovarian abscess
Ectopic pregnancy

Adenocarcinomas constitute the majority of colorectal cancers, although lymphoma and Kaposi sarcoma also occur. Benign colonic masses may be due to perforation of an inflamed appendix, selected infections (e.g. amebiasis), or inflammation from Crohn’s disease. The appearance of colorectal cancer can be mimicked by colitis cystica profunda, a benign disease characterized by submucosal mucus-filled cysts. Carcinoids arise most commonly in the appendix, followed by the ileum, rectum, and stomach. Gastrinomas may originate in the pancreas or in the proximal bowel wall. Tumors originating from smooth muscle (leiomyoma, leiomyosarcoma) or fat (lipoma, liposarcoma) may be seen throughout the digestive tract. Less common cell types include neurofibromas, schwannomas, and leioblastomas.

Miscellaneous masses

Miscellaneous lesions may present as abdominal masses. Renal masses may be infectious, neoplastic, or congenital. The most common malignancy is renal cell carcinoma. Other neoplasms include transitional cell carcinoma of the renal pelvis with parenchymal invasion, lymphoma, and renal oncocytoma. Renal cysts most commonly are benign but may harbor carcinoma, especially in patients with von Hippel–Lindau or tuberous sclerosis. Cystic masses in the mesentery include mesenteric cysts, cystic teratomas, and cystic mesotheliomas. A hematoma is considered in any patient with a history of blunt abdominal trauma. Abdominal aortic aneurysms may be detected as pulsatile abdominal masses. Gynecological masses involving the ovaries or uterus may be palpable on abdominal examination.