Why isn't it "multiple scleroses"?

https://lemmy.world/post/19621122

Why isn't it "multiple scleroses"? - Lemmy.World

Because the disease name isn’t a plural of scleros.

Sclerosis (from the greek skleros meaning hard) is the stiffening of tissue.

i think they know that. if you pluralized ‘sclerosis’, you’d expect to get ‘scleroses’. just like pluralizing ‘thrombosis’ gets you ‘thromboses’.
The disease isn’t a plural. Which i already said.
Scleroses would translate as “hardening diseases” though. There’s only one disease.