Hi Sameet,
I think this is a really important case for everyone to enjoy,
I have pondered over this appearance myself many times,
Today I consider it is a pretty typical full thickness tear.
The echogenic material is sitting in a hole in the tendon,
It can be one of two things.
In your case I think it is peribursal fat that has subluxed into the tendon defect.
The other option (less likely in this case) is that it is a clot (haematoma)
Either way it is a full thickness tear,
A great thing to do is ask the patient to abduct their shoulder while you watch it and you will see that the echogenic material has no connection to the tendon stump and is often squeezed out during dynamic assessment.
Ahhh, one of the great advantages of ultrasound : Dynamic assessment !
Great images Sameet,
Please keep them coming,
Steve.