I had a full tummy tuck 8 weeks ago and I have a seroma. Not sure what to do. Will it encapsulate or cause deformity? (Photo)

I'm sorry to hear of the issues you are having with seroma development. It would not be unusual for a seroma the size you have to require multiple aspirations. I encourage you to contact your surgeon as you have noticed it increasing in size.

Seromas are a known complication after abdominoplasty due to the large space that is created, disruption of lymphatic channels, and inflammation after surgery. Usually these can be managed with in-office aspirations. 
340 cc of aspiration is a large amount of fluid, which suggests that serial applications may be needed as seromas are likely to return in the short term. Aspirating them frequently in the office may help prevent the development of encapsulation, therefore it is wise to follow up with your surgeon and see if they need to be aspirated on a frequent basis. 
In my practice, if a large seroma develops after a procedure I may try to see the patient every few days for aspirations. If the amount has gone down significantly then I may wait longer before aspirating. It is possible, based on your symptoms, that a new, larger seroma has formed so a call to your surgeon's office for a sooner appointment may be warranted. 
Should encapsulation occur, treatment options may include surgical drainage and removal of the capsule or injection of a sclerosing agent to close the space down. 
I offer my patients a "drainless" tummy tuck whereby no drains are used and a technique called progressive tension is performed to close the space and prevent seroma development. 
Best wishes, 
Rohit Jaiswal, MD
Plastic Surgeon; Las Vegas, NV 

Thank you for this question. Unfortunately seromas happen from time to time after tummy tuck. You may need multiple drainages of the seroma in order to completely get rid of it and you may also need a procedure to sclerose the seroma where a substance such as Betadine or doxycycline is injected into the seroma cavity. 
If this is ignored, it can very well be encapsulated and you may need a surgical procedure for revision. 
Please follow up with your plastic surgeon ASAP in order to figure what your next course of treatment will be.
Best wishes! 
Rahul Vemula, MD 
Double Board Certified Plastic and Reconstructive Surgeon