Healthy Cat suddenly presenting with one soft, fluid-filled cyst.

My healthy, 9 year old, male Ginger cat suddenly presented with a 2 x 2 cm (diameter) cyst on the "shoulder" of his right front leg. We handle him frequently and this is definitely a new development. We immediately took him to the vet, who shaved the area and drained the cyst with a needle. Clear fluid came out. After doing this he said that he felt that it was a parasitic infection caused by a mosquito bite. He then went on to say that if he administered treatment and there were many parasites, the cat may go into shock and die (parasites will die and end up in cats lungs or something). On the other hand, if there are one or two parasites, administering treatment with have no effect. I was absolutely devastated as it felt like he was handing a death sentence to my cat. He is going in for tests on Friday, however, I would like to ask how the vet could've come to such a dire diagnosis by just draining the cyst? I looked up "cat cysts" on Google and read that it was "common"? Any advice would be greatly appreciated.

Cysts are common but presumably have many causes, and I suspect the one your vet is suggesting is rare.

Think you need to ask your vet how he/she reached their conclusion and what parasite they suspect.

Also, people will probably assume you are somewhere in the US since you haven't put a location on your profile.  Suggest you do that.  This sounds like the sort of issue that might be affected by where you live.

Yes, it seems to be region specific.

We took Ginger to a second vet this afternoon to get a second opinion and some clarity on the matter.

The vet said that, unlike the strain that is prevalent in the USA, the parasite is nonpathogenic in South Africa.

I think that they are the same Microfilariae that are present in Heartworm cases, they just don't mature into adults.

Ginger will be booked in tomorrow and tests will be done to establish how many parasites he has in his bloodstream.

The vet explained that, though some cats have bad reactions to the treatment, cats with good immune systems wouldn't necessarily react as badly.

Treatment in cats with weakened immune systems has been known to cause pulmonary edema.

I'm still very nervous, but I'm glad that both vets will jointly be attending to Ginger tomorrow.

Please check your PMs.  I sent you a very important private message. 

I really appreciate the info Violet, thank you.   So, Ginger went in this morning and had preliminary tests done to see how many parasites he had in his bloodstream. I sat, with baited breath, waiting for the phone to ring. When the call eventually came, the vet told me that he could not find any Microfilariae in Ginger's bloodstream and that they were going to send his blood to an independent lab to confirm the results. I'm not going to jump up and down just yet, but it's certainly a good thing that no Microfilariae were found so far!