I had a salivary gland removal surgry about 6 month back. developed below my jaw & it sized a table tennis ball. wat cud b the reason for this?

Hard to Say: It could have been a blocked duct-often caused by infection but infection can also cause the clockaged. It could have been a benign tumor growth. If it was soft to the touch, it was more likely from blockage. Whoever removed the gland should have sent it to pathology-have you contacted them? That would be the only way to know for certain the cause and whether or not you might have further issues.

Multiple reasons: I agree with dr. Goodpaster, good answer. I would add that although there are a number of reasons for a gland to become enlarged (blocked duct due to sialolith), bacterial or viral infection, there are fewer reasons for complete gland removal. This is more commonly performed if there is a growth (either benign tumor or a cancerous growth). Less commonly can be removed for persistent infection.