Nimbus is a 14 year-old male neutered cat minimally overweight presented for wellness care. Subcutaneous masses were palpable in the region of the cranial two nipples and inverted nipples with inspissated secretions were suspected. The secretions were expressed under anesthesia.
Inverted nipples occur in man, cats, and I am sure many other mammals. Inverted nipples and inspissated secretions are not uncommon in cats. Over time, the cats, continue to make sebum and exfoliate dead skin from the nipple. In time (as with furuncles) these ‘cysts’ continue to enlarge and the material becomes inspissated. Sometimes the concretions are very large (0.5 x 1 cm) and really fun to express.
I would imagine that as they become larger, the cats can sense the presence and I would think they would feel relief after they are expressed. Maybe I am anthropomorphizing too much. I don’t recall seeing them become infected, .