Does anyone have experience with: unknown mass in cat's chest?

Question

( Please note we live in a developing country with limited veterinary resources )

Our one year old, short hair, domestic calico started having what we thought was chest congestion / respiratory infection a few days ago: rattling sound in chest, wheezing, whistling breath when excited, swallowing difficulty, vomiting portions of meal during eating them (gag reflex triggered while eating). On about third day we took her to vet who did X-ray (attached) to find a mass of some sort in front of chest, pushing at and up on trachea causing it to almost close. .

Vet does not think it is an infection as her colours are good, no running nose, and the mass seems very well-formed. Surgery is not a straight-off option as vet does not have scoping equipment so would be opening her up 'blind' and mass seems to be under the ribs and under some blood vessels. Vet is ready to do surgery if we insist, but does not think she will survive the act of being put under. Vet has commented that if this is a tumour it is very very strange for a cat so young.

Vet gave her a shot of steroids and antibotics (on the off chance it is infection-based) at 3.30 pm yesterday, a 24 hour dose. By 9 pm she was breathing normally, with no more wheezing. She did vomit last night but kept her breakfast in this morning. Still, no wheezing this morning but as morning has progressed we can see that breathing is a little more troublesome than last night and she is opting to rest more than last night, I am assuming this is because the steroids are wearing off. I am going to ask vet this evening if we can get another cocktail injection tomorrow morning, to keep the momentum going if it is indeed infection-based. I'm thinking now we should have also done blood tests to see if body was responding to an infection at all, before we started her on antibiotics.

I have a theory (which might be way off): about 5 months ago she jumped off of our balcony as she was afraid of some visitors we had in the house. We could not anticipate she was going to make this decision, she raced out the door and leaped off in a split second. Our balcony is one floor above ground level. On her way down her neck and chest slammed into the stairs' railing. In the hours/days that followed she showed absolutely zero sign of pain, discomfort or injury as a result of this, and as she is a very very nervous skittish cat, we decided not to take her to the vet to investigate if there were any resulting issues. Could it be possible that a fragment of bone or cartilage in her chest dislodged and embedded itself in any surrounding tissue, and has been building up scar tissue around itself?

I appreciate any other ideas, feedback and suggestions.

Answer 1

Creating an answer based on comments under question, some of them from OP who has not returned to site in several years.

More X-rays and the results of a needle biopsy would help in identifying the cause and cure.

In this case, a series of shots with steroids and antibiotics lead to the mass decreasing. Followed by oral medications as the swelling decreased, allowing the cat to swallow. Ultimately disappearing completely. The working hypothesis is:

"Little plant-prickle/thorn had worked its way in from outside and caused the infection which would explain why it was showing as a well-formed mass and not the usual-spread out goopy form of an infection"

There has been no further contact from the OP since 3 weeks after the initial event, which was also the time the OP said:

The day after we took her for review and vet said her breathing had normalised and all wheezing had gone, so then put her on further 2 weeks of oral antibiotics and steroids. After 2 weeks she had second X-ray and - JOY - the mass had completely DISAPPEARED. She went on another one week of antibiotics and steroids just to be safe and now she is completely back to normal, full of energy and actually in a much better mood than she had been the past few months.