Brief Answer:
Possibilities as mentioned. Please give some additional information.

Detailed Answer:
Hi.
Thanks for your query, albeit short.

Please provide some additional information for me to assist you better:

Since when has this developed?
Is the bulging in the lower abdomen or at another area of the abdomen?
Any gastrointestinal or urinary complaints?
Where is the pain and type of it?
Does the swelling increase and decrease or is stationary?

Any other information, please.

The most probable causes I can think about at your age and should be ruled out are as follows:
Any cyst or tumor.
Ascites (fluid in the abdominal cavity).
Intestinal obstruction.

Surely needs clinical evaluation, examination and investigations to know the exact cause.

I hope this answer helps you.
Awaiting your feedback.

With Regards,
Dr. T Chandrakant.
General Surgeon.

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