Abdomen differential diagnosis
Abdominal alternatives are grouped by organ of origin and by the pattern of enhancement, obstruction or displacement. Use the clue column to see which feature argues against the alternative.
| Alternative diagnosis | Feature that argues against it | Case |
|---|---|---|
| Abdominal malignancy | A retroperitoneal or pancreatic malignancy encases or invades the vessel with soft-tissue mass, lymphadenopathy and weight loss, and does not produce a smooth hook-like indentation. | Coeliac artery compression by the median arcuate ligament |
| Abdominal wall lipoma | A lipoma is a homogeneous fat-density mass within the subcutaneous tissue or muscle, without a fascial defect or a neck connecting it to the peritoneal cavity. | Spigelian hernia |
| Appendiceal mucocele | An appendiceal mucocele is a tubular cystic mass continuous with the caecum and does not show splenic enhancement or an absent spleen. | Torsion of a wandering spleen |
| Atherosclerotic coeliac stenosis | Atherosclerotic stenosis occurs in older patients with calcified plaque at the vessel origin and is fixed, without the expiratory accentuation of median arcuate ligament compression. | Coeliac artery compression by the median arcuate ligament |
| Carcinoid tumour | A carcinoid is usually small, intensely enhancing and associated with mesenteric desmoplastic reaction and calcification, rather than a large necrotic exophytic duodenal mass. | Synchronous duodenal GIST and colorectal adenocarcinoma |
| Diverticulitis | Diverticulitis shows wall thickening, fat stranding, fluid and possibly an abscess around the diverticula, whereas uncomplicated diverticulosis has no inflammatory change. | Small bowel diverticulosis |
| Emphysematous gastritis | Emphysematous gastritis is a life-threatening infection with marked wall thickening, fluid, sepsis and gas dissecting into the portal venous system, unlike the thin-walled distended stomach here. | Gastric pneumatosis due to gastric outlet obstruction |
| Fibrolamellar carcinoma | Fibrolamellar carcinoma occurs in young patients without cirrhosis, is a large heterogeneous mass with a central scar and calcification, and does not produce a diffusely nodular liver. | Macronodular liver cirrhosis with ascites |
| Focal fatty infiltration of the pancreas | Focal fatty infiltration is geographic, has no capsule or mass effect, follows the lobular architecture and shows normal enhancing pancreatic tissue within it. | Pancreatic lipoma |
| Functional abdominal pain | Functional abdominal pain has no vascular abnormality, whereas this case shows a reproducible anatomic narrowing with elevated velocities and post-stenotic dilatation. | Coeliac artery compression by the median arcuate ligament |
| Fungal microabscess | Fungal lesions are multiple, small, often with a target appearance and restricted diffusion, and occur in immunocompromised febrile patients. | Primary hepatic follicular lymphoma |
| Gastric emphysema | Gastric emphysema is intramural gas without obstruction or severe illness that resolves with conservative treatment, whereas this case shows a clear outlet obstruction causing the pneumatosis. | Gastric pneumatosis due to gastric outlet obstruction |
| Gastric volvulus | Gastric volvulus produces a distended, twisted stomach with a bird-beak transition and may cause ischaemia, but the classic double-bubble or organo-axial configuration is absent here. | Gastric pneumatosis due to gastric outlet obstruction |
| Gastrointestinal haemangioma | A haemangioma shows strong, persistent enhancement with phleboliths and no central necrosis, and it is not associated with a synchronous colonic tumour. | Synchronous duodenal GIST and colorectal adenocarcinoma |
| Gastrointestinal sarcoma | A high-grade sarcoma is large and heterogeneous with necrosis and haemorrhage, but the presence of two distinct primary tumours makes a synchronous second primary more likely than a single sarcoma. | Synchronous duodenal GIST and colorectal adenocarcinoma |
| Hepatic metastasis | Metastases are usually multiple, hypodense and rim-enhancing with a known primary, and they do not follow the diffuse nodular contour of cirrhosis. | Macronodular liver cirrhosis with ascites |
| Hepatocellular carcinoma | Hepatocellular carcinoma shows arterial hyperenhancement with portal venous or delayed washout and may invade the portal vein, whereas regenerative macronodules remain isodense in all phases. | Macronodular liver cirrhosis with ascites |
| Leiomyosarcoma | Leiomyosarcoma arises from smooth muscle, often in the small bowel, and shows marked necrosis and heterogeneous enhancement, but it does not explain the separate colonic adenocarcinoma. | Synchronous duodenal GIST and colorectal adenocarcinoma |
| Lipomatous pseudohypertrophy | Lipomatous pseudohypertrophy replaces most of the pancreas diffusely with fat and is associated with atrophy of the pancreatic parenchyma, rather than forming a discrete mass. | Pancreatic lipoma |
| Lymph node | An enlarged lymph node is homogeneous, has a fatty hilum and enhances less than spleen, without a bridging splenic vessel. | Accessory spleen confirmed on histology |
| Meckel diverticulum | A Meckel diverticulum is a single outpouching on the antimesenteric border of the distal ileum, not multiple diverticula distributed along the small bowel. | Small bowel diverticulosis |
| Mesenteric cyst with small bowel volvulus | A mesenteric cyst is fluid-density with a thin wall and does not enhance like spleen, and the whirl sign involves bowel and mesentery rather than a splenic pedicle. | Torsion of a wandering spleen |
| Metastatic disease | Metastases are usually multiple, show ring enhancement and are associated with a known primary tumour, and they do not have the homogeneous mild enhancement of lymphoma. | Primary hepatic follicular lymphoma |
| Multifocal hepatocellular carcinoma | Multifocal HCC produces discrete enhancing nodules with washout and tumour thrombus, unlike the diffuse, non-enhancing regenerative nodules of macronodular cirrhosis. | Macronodular liver cirrhosis with ascites |
| Neuroendocrine tumour | A pancreatic neuroendocrine tumour is hypervascular in the arterial phase but shows washout and may be associated with hormonal symptoms, and it does not enhance in parallel with the spleen. | Accessory spleen confirmed on histology |
| Other abdominal wall hernia | Inguinal, femoral and ventral hernias occur at their own anatomic landmarks and are not located lateral to the rectus muscle at or below the arcuate line. | Spigelian hernia |
| Ovarian torsion | Ovarian torsion produces an enlarged, oedematous adnexal mass with peripheral follicles and a twisted ovarian pedicle, and the spleen remains in its normal position. | Torsion of a wandering spleen |
| Pancreatic ductal adenocarcinoma | Adenocarcinoma is a solid, hypovascular mass that obstructs the pancreatic duct and causes upstream atrophy, without fat attenuation. | Pancreatic lipoma |
| Pancreatic liposarcoma | A liposarcoma is larger, heterogeneous with thick septa and nodular enhancing soft-tissue components, and it may invade adjacent structures. | Pancreatic lipoma |
| Papillary epithelial neoplasm | A solid pseudopapillary neoplasm of the pancreas is usually a large, heterogeneous cystic-solid mass in a young woman that enhances less than spleen and does not have a bridging vessel to the spleen. | Accessory spleen confirmed on histology |
| Pneumatosis intestinalis | Pneumatosis intestinalis is gas within the bowel wall itself, often linear or cystic, and is not a set of epithelial-lined outpouchings. | Small bowel diverticulosis |
| Pneumoperitoneum | Pneumoperitoneum shows free gas outside the bowel lumen, often under the diaphragm, rather than gas confined within the gastric wall. | Gastric pneumatosis due to gastric outlet obstruction |
| Reactive lymphoid hyperplasia | Reactive lymphoid hyperplasia is a small benign nodule that is usually isointense to liver and does not show the restricted diffusion and progressive enhancement of lymphoma. | Primary hepatic follicular lymphoma |
| Rectus sheath haematoma | A rectus sheath haematoma is a fluid or blood-density collection within the rectus sheath, often after anticoagulation or trauma, without a fascial defect. | Spigelian hernia |
| Renal mass | A renal mass arises from the kidney, shows renal enhancement and preserves a normal spleen in the left upper quadrant. | Torsion of a wandering spleen |
| Secondary hepatic lymphoma | Secondary lymphoma is accompanied by widespread lymphadenopathy, splenic involvement and systemic B symptoms, whereas this lesion is isolated to the liver without other disease. | Primary hepatic follicular lymphoma |
| Small bowel neoplasm | A small bowel neoplasm produces a focal mass or wall thickening that enhances and may obstruct or bleed, without multiple thin-walled outpouchings along the mesenteric border. | Small bowel diverticulosis |
| Spigelian hernia with strangulation | Strangulation would show bowel wall thickening, reduced enhancement, fluid in the sac and obstruction, none of which are present in this case. | Spigelian hernia |
| Superior mesenteric artery thrombosis | SMA thrombosis produces an occluded or severely narrowed artery with bowel ischaemia and a non-enhancing bowel wall, rather than extrinsic compression of the coeliac trunk. | Coeliac artery compression by the median arcuate ligament |
| Vascular metastasis | A hypervascular metastasis shows arterial enhancement with washout, is often multiple and is associated with a known primary tumour. | Accessory spleen confirmed on histology |
The confirmed diagnosis of each case is stated on the case page and is not repeated here. Sorted alphabetically; the order says nothing about probability.