Organomegaly

Organomegaly is the abnormal enlargement of organs. For example, cardiomegaly is enlargement of the heart. Visceromegaly is the enlargement of abdominal organs.^[1] 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 cm[2]
	Abdominal aortic aneurysm	Moderate AAA: 3.0–5.0 cm[2] Large or severe AAA: >5.0[2] or 5.5.[3] cm
Common bile duct	Dilatation	Mild dilatation:[4] 8–12 mm Moderate dilatation:[4] 12–16 mm Severe dilatation:[4] 16–20 mm Extremely severe dilatation:[4] >20 mm
Gallbladder	Wall thickening	3 mm wall thickness[5]
	Hydrops	Greater than 5 cm transverse dimension[6]
Heart	Cardiomegaly	Medical imaging: Indicated by cardiothoracic ratio over 0.5.[7] Autopsy: Cardiomegaly has been suggested when the heart weighs more than >399 grams in women and >449 grams in men.[8]
Large intestine	Dilation	Upper limit of normal range of diameter:[9] 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[10]
Kidneys	Enlargement	Medical imaging: Length >13 cm in females or >14 cm in males.[11] Autopsy: Sex Upper limit of standard reference range Right kidney Left kidney Men[12] 160 g (5.6 oz) 175 g (6.2 oz) Women[13] 175 g (6.2 oz) 190 g (6.7 oz)
Liver	Hepatomegaly	Medical imaging: Longitudinal axis > 15.5 cm at the hepatic midline, or > 16.0 cm at the midclavicular line[14] Autopsy: Weight over upper limit of standard reference range, of 1,860 g (4.10 lb) in men[12] and 1,770 g (3.90 lb) in women.[13]
Lymph nodes	Lymphadenopathy	Generally 10 mm[15][16] (see Lymphadenopathy) for detailed values)
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.[17] Adults: cutoff values defined differently by different sources, with anteroposterior diameters ranging between 10 and 20 mm.[18] About 13% of normal healthy adults have a transverse pelvic diameter of over 10 mm.[19]
Prostate	Prostatomegaly	Volume over 30 cm3.
Pulmonary artery	Dilation	>29 mm[20]
Small intestine	Dilation	2.5 cm on CT scans[21][22] Mild: 2.5–2.9 cm[23] Moderate: 3-4 cm[23] Severe: >4 cm[23] 3 cm on abdominal X-rays[21][24] (Projectional radiography confers a geometric magnification compared to CT[25])
	Wall thickening	3–5 mm[26]
Spleen	Splenomegaly	Medical imaging: Largest dimension of over 11 cm,[27][28] or craniocaudal height of 13[29] cm. Moderate splenomegaly: the largest dimension is between 11–20 cm[27] Severe splenomegaly: the largest dimension is greater than 20 cm[27] Autopsy: Weight over upper limit of standard reference range, of 230 g (8.1 oz)[12][13]
Thoracic aorta	Dilation	Diameters: >3.5 cm generally[30] Upper limits of standard reference range: Ascending aorta: 3.3 cm in small young individuals[31] 4.3 cm among large elderly individuals.[31] Descending thoracic aorta, 2.3 cm among small young individuals[31] 3.2 cm among large elderly individuals.[31]
	Thoracic aortic aneurysm	Diameter: > 4.5 cm (US)[30] > 4.0 cm (Korea)[32]
Testis	Enlargement	5 cm (long axis) x 3 cm (short axis)[33]
Tonsil	Enlarged tonsil	2.5 cm in length, 2.0 cm in width and 1.2 cm in thickness.[34]
Ureter	Megaureter	6[35] or 7[36] mm
Urinary bladder	Wall thickening	3–5 mm thick, and < 3 mm when well distended.[37]