Can you post come images of the lens? Lenses can also get dry condensation in spots that get mistaken for fungus. Fungus- will look like threads from a spider web coming from the center.
I treat these by getting to the glass surface, meaning using a Spanner. Cheap on Ebay.
I use Lens-Cleaner on a Q-Tip, lens cleaner having alcohol and ammonia mix. Use a very light touch with the Q-Tip, then follow up with lens cleaning paper.
Use a UV-Lamp, NOT UV-C as it will not penetrate through glass to the other sections of the lens. Run for a few hours.
I recently bought a small collection of Contax and Nikon gear- had been stored in a safe by the Widow of the owner. I spent weeks going through the gear, disassembling, cleaning, and treating with UV. The many pieces are Okay. I have been using this technique for decades, it works.
Usually on a lens- the Fungus is long dead, and etches the coatings and glass, it is like an acid. If you get to it quickly, leaves no damage. I was able to completely clean up all but one of the lenses in the collection, about a Dozen Nikon S-mount, F-Mount, and Contax RF Mount including a 21mm F4.5. The widow would have had to pay $150~$300 per piece to have a professional shop do the work.
