A newborn child presents with solitary white well defined hypopigmented patch on his right thigh. Diagnosis is :
**Core Concept**
The condition described is a type of benign skin lesion that is characterized by a well-defined, hypopigmented patch, often seen in infants and children. This condition is caused by a localized area of epidermal thinning and is thought to be related to an abnormality in melanin production.
**Why the Correct Answer is Right**
The condition described is likely a Mongolian spot, also known as a congenital dermal melanocytosis. This is a benign condition that typically presents as a blue or grayish patch on the lower back or buttocks of newborns, but can also occur on other areas of the body. The exact cause of Mongolian spots is not fully understood, but it is thought to be related to an abnormality in the migration of melanocytes during fetal development.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the description of a solitary white, well-defined hypopigmented patch on a newborn.
* **Option B:** This option is incorrect because it is a type of skin lesion that is typically associated with an infectious process, such as a fungal or bacterial infection.
* **Option C:** This option is incorrect because it is a type of skin lesion that is typically associated with a genetic disorder, such as neurofibromatosis.
**Clinical Pearl / High-Yield Fact**
Mongolian spots are benign and do not require any treatment, but they can be mistaken for other conditions, such as vitiligo or albinism. It is essential to perform a thorough examination and consider the patient's age and medical history when evaluating a solitary hypopigmented patch.
**Correct Answer: C.**