At first this sentence does not seem to be grammatically correct. I would assume that 'mysterious diseases pathology' would be a branch of pathology. In this case diseases would be an adjective. In conjunction with 'mysterious', the word describes pathology.
part of speech
The suffix usually indicates the procedure, condition, disease, or the part of speech (ex. noun, adjective, etc.)
The word "healed" can function as both a verb and an adjective. As a verb, it is the past tense of "heal," meaning to restore to health. As an adjective, it describes something that has been made whole or free from injury or disease. The context in which it is used determines its part of speech.
Adjective
What part of speech is thaw
"Hydrophobia" is a noun, the name of a disease.
It is a noun because it is the name of a disease
The word pneumonoultramicroscopicsilicovolcanoconiosis is a noun. It was coined by Everett K Smith and is a factitious disease of the lungs.
part of speech
The part of speech for this particular word is a noun.
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
Contract is a noun and a verb, but they are pronounced differently. Noun: Please sign the contract. Verb: Kylie contracted a rare disease.
The suffix usually indicates the procedure, condition, disease, or the part of speech (ex. noun, adjective, etc.)
The part of speech for "explicit" is an adjective.
The part of speech for "twirl" is a verb.