**Question:** Remnant vitelline duct causes -

A. Hydatid cyst of liver
B. Hydatid cyst of spleen
C. Hydatid cyst of lungs
D. Hydatid cyst of kidney

**Core Concept:** Vitelline duct is a structure that develops during embryogenesis and plays a role in the development of the liver and gallbladder. In some cases, remnants of this duct may persist and lead to various complications.

**Why the Correct Answer is Right:** The correct answer, A, refers to a cyst (abnormal growth) caused by the persistence of the vitelline duct. This cyst, known as a hydatid cyst, can develop in the liver due to its close proximity to the vitelline duct. Hydatid cysts are caused by the Echinococcus granulosus parasite, which is usually contracted through ingesting eggs from infected animals.

**Why Each Wrong Option is Incorrect:**

B. Hydatid cyst of spleen: This option is incorrect because the spleen is distant from the vitelline duct and hydatid cyst is more commonly associated with the liver.

C. Hydatid cyst of lungs: Although the vitelline duct is not directly related to lung disease, the parasite can sometimes be transmitted to the lungs via bloodstream, causing hydatid cyst in the lungs.

D. Hydatid cyst of kidney: Similar to option C, the hydatid cyst can sometimes reach the kidneys via the bloodstream, but it is less common compared to the liver and lungs. The kidneys are more distant from the vitelline duct compared to the liver and lungs.

**Clinical Pearl:** The persistence of the vitelline duct can lead to various complications due to the close proximity of the liver and its adjacent structures. It is essential for medical students and healthcare professionals to understand the potential complications and their clinical implications for appropriate diagnosis and management of patients with liver abnormalities.

**Correct Answer:** A. Hydatid cyst of liver