Organomegaly is the abnormal enlargement of organs. For example, cardiomegaly is enlargement of the heart. Visceromegaly is the enlargement of abdominal organs. Examples of visceromegaly are enlarged liver (hepatomegaly), spleen (splenomegaly), stomach, kidneys, and pancreas.
Definitions for various organs Values refer to adults unless otherwise specified. Organ Term for enlargement Cutoff for definition Abdominal aorta Ectasia or mild dilation>2.0 cm and <3.0 cmPage 56 in: Abdominal aortic aneurysm Moderate AAA: 3.0–5.0 cm Large or severe AAA: >5.0 or 5.5. cm Common bile duct Dilatation Mild dilatation: 8–12 mm Moderate dilatation: 12–16 mm Severe dilatation: 16–20 mm Extremely severe dilatation: >20 mm Gallbladder Wall thickening 3 mm wall thickness Hydrops Greater than 5 cm transverse dimensionPage 256 in Heart Cardiomegaly Medical imaging: Indicated by cardiothoracic ratio over 0.5. Autopsy: Cardiomegaly has been suggested when the heart weighs more than >399 grams in women and >449 grams in men. Large intestine DilationUpper limit of normal range of diameter: Cecum: 10.5 cm Ascending colon: 7.0 cm Transverse colon: 6.5 cm descending colon and sigmoid colon: 6.8 cm Rectum near rectal/sigmoid junction: 7.5 cm Wall thickening Wall thickness 5 mm Kidneys Enlargement Medical imaging: Length >13 cm in females or >14 cm in males. Autopsy: Sex Upper limit of standard reference range Right kidney Left kidney Men Women Liver Hepatomegaly Medical imaging: Longitudinal axis > 15.5 cm at the hepatic midline, or > 16.0 cm at the midclavicular line Autopsy: Weight over upper limit of standard reference range, of in men and in women. Lymph nodes Lymphadenopathy Generally 10 mm Renal pelvis Part of hydronephrosis grading 4 – 20 mm: Fetal: Anteroposterior diameter of less than 4 mm in fetuses up to 32 weeks of gestational age and 7 mm afterwards.Page 189 in: Adults: cutoff values defined differently by different sources, with anteroposterior diameters ranging between 10 and 20 mm.Page 78 in: About 13% of normal healthy adults have a transverse pelvic diameter of over 10 mm. Prostate Prostatomegaly Volume over 30 cm3. Pulmonary artery Dilation >29 mm Small intestine Dilation 2.5 cm on CT scans Mild: 2.5–2.9 cm Moderate: 3-4 cm Severe: >4 cm 3 cm on abdominal X-rays (Projectional radiography confers a geometric magnification compared to CT) Wall thickening 3–5 mm Updated: Sep 22, 2016 Spleen Splenomegaly Medical imaging: Largest dimension of over 11 cm, Updated Apr. 2012 (referring the classification system to Poulin et al.Page 1964 in: or craniocaudal height of 13 cm. Moderate splenomegaly: the largest dimension is between 11–20 cm Severe splenomegaly: the largest dimension is greater than 20 cm Autopsy: Weight over upper limit of standard reference range, of Thoracic aorta Dilation Diameters: >3.5 cm generally Upper limits of standard reference range: Ascending aorta: 3.3 cm in small young individuals 4.3 cm among large elderly individuals. Descending thoracic aorta, 2.3 cm among small young individuals 3.2 cm among large elderly individuals. Thoracic aortic aneurysm Diameter: > 4.5 cm (US) > 4.0 cm (Korea) Testis Enlargement 5 cm (long axis) x 3 cm (short axis)Page 559 in: Tonsil Enlarged tonsil 2.5 cm in length, 2.0 cm in width and 1.2 cm in thickness. Ureter Megaureter 6 or 7Page 140 in: mm Urinary bladder Wall thickening 3–5 mm thick, and < 3 mm when well distended.Page 12 in:
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