Apple-core lesion

An apple-core lesion refers to a short segment where the large bowel becomes narrowed all the way around, with abrupt edges seen on imaging, producing an appearance reminiscent of the remains of an eaten apple – an apple core lesion.

This appearance is most commonly associated with colonic adenocarcinoma, a cancer of the large bowel. It arises because the tumour grows circumferentially within the bowel wall, gradually narrowing the hollow centre (lumen) rather than forming a single lump. When a contrast liquid is used to outline the bowel, only a thin column can pass through the narrowed segment, and it is this narrow column that outlines the characteristic apple-core shape. The finding is therefore an important radiological clue that often leads to further investigation, such as colonoscopy and biopsy.

Reference 

Alzaraa A, Krzysztof K, Uwechue R, Tee M, Selvasekar C. Apple-core lesion of the colon: a case report. Cases J. 2009;2:7275. Go to reference

                                                        Apple-core lesion, Apple core

Image from Alzaraa et al.

Tea-coloured urine

Urine is usually pale yellow. Tea-coloured urine refers to urine that appears dark brown, resembling strong tea. This change in colour can occur for several reasons, ranging from dehydration to medical conditions.

Tea-coloured urine can occur because substances in the urine alter its colour. These include blood-related pigments such as haemoglobin (from red blood cell breakdown) and myoglobin (from muscle injury). Tea-coloured urine can also be seen with some urinary tract infections and with some medications. Liver and bile duct problems may cause dark urine when bilirubin is excreted into the urine.

Reference 

Barsanti-Innes B, Koda Y, Hsia CC, Chin-Yee B. A 34-year-old man with tea-coloured urine. CMAJ. 2025;197(41). Go to reference

See also Coca-cola colored urine

Tea-coloured urine, Tea with mint

Image from Wikimedia Commons

Image from Wikimedia Commons

Oreo cookie sign in pericardial effusion

Pericardial effusion occurs when fluid builds up in the pericardium, the double-layered membrane that surrounds and protects the heart. This abnormal fluid buildup can be caused by infections, trauma, cancer, autoimmune diseases and other conditions.

The Oreo cookie sign describes a distinct pattern seen on medical imaging. On chest X-rays or more detailed scans, like a computed tomography (CT) scan (which uses special X-ray technology), the fluid in the pericardium forms the "cream" layer in the middle, with the outer layers of the “cookie” made up of the pericardial and epicardial membranes. Echocardiography, which uses sound waves to create real-time images of the heart, can also reveal this pattern.

The Oreo cookie sign is an important clue for diagnosing pericardial effusion, which can be serious. If the fluid buildup is large enough, it can lead to cardiac tamponade, a condition where the heart is compressed and cannot pump blood properly. Early detection and treatment are crucial to prevent complications.

Reference

Chiarenza A, Esposto Ultimo L, Falsaperla D, Travali M, Foti PV, Torrisi SE, Schisano M, Mauro LA, Sambataro G, Basile A, Vancheri C, Palmucci S. Chest imaging using signs, symbols, and naturalistic images: a practical guide for radiologists and non-radiologists. Insights Imaging. 2019;10(1):114. Go to reference

Oreo cookie sign, Oreo cookie

Image from Chiarenza A et al. Insights Imaging. 2019.

Fried egg appearance of Best disease

Best disease, or Best vitelliform macular dystrophy, is an inherited eye condition affecting the macula, the central region vital for clear vision. Typically appearing in childhood or adolescence and progressing over time, it results in central vision loss. Named after German ophthalmologist Dr. Friedrich Best, who observed a family with various stages of the disease in 1905. Best disease can reveal a distinctive fried egg appearance in the macula. This look, resembling a yellowish egg yolk, is caused by the buildup of lipofuscin, a fatty substance, in the retinal pigment epithelium cells. These cells support the retina, the light-sensitive layer of tissue in the eye. Imaging techniques, like fundoscopy, allow us to see this fried egg appearance.

Reference

Tripathy K, Salini B. Best Disease. [Updated 2023 Aug 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Go to reference

Fried egg appearance, Fried egg

Image from Nentwich MM, Rudolph G. Hereditary retinal eye diseases in childhood and youth affecting the central retina. Oman J Ophthalmol. 2013.

Candy cane aorta

The largest and main artery in the human body, the aorta, emerges from the heart. The aorta distributes oxygenated blood to all parts of the body. The aorta gives off various branches as it travels through the thorax and abdomen. The aorta's arch, which is curved and located in the thorax, joins the ascending and descending aortas. When examined from a side angle using X-rays or magnetic resonance imaging, the configuration of the ascending aorta, aortic arch and descending aorta resembles a candy cane or hockey stick in appearance – candy cane aorta.

In the abdomen, the aorta ends by splitting into the median sacral artery, a small midline vessel and the common iliac arteries, two major blood vessels. 

Reference:

Eikendal AL, Bots ML, Haaring C, Saam T, van der Geest RJ, Westenberg JJ, den Ruijter HM, Hoefer IE, Leiner T. Reference values for cardiac and aortic magnetic resonance imaging in healthy, young caucasian adults. PLoS One. 2016;11(10):e0164480. Go to reference.

Candy cane aorta, candy cane

Image from Eikendal AL et al. PLoS One. 2016.