system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Angiofibroma bleeds excessively because -
assistant
The correct answer is  The characteristic of JNA is that the vessels are just endothelial - lined spaces with no muscle coat.
As the contractile component (muscle coat) of vessels is absent, vessels have no ability to contract, i.e. vasoconstriction does not occur, and this accounts for :-


Severe and recurrent epistaxis
Bleeding cannot be controlled by application of adrenaline, a potent vasoconstrictor.