It is difficult to respond to your question without having a better understanding of the facts and background of why each party did what you say they did. Was the person who held onto your property your landlord? Was your property located at another person's house/property? Why was it there? Did you allow this "individual" to use your property and if so, on what terms? Is there a written agreement about what the "individual" was allowed to do with your property or what he was required to do with it?
Generally speaking, if a person, without permission to do so, takes/steals your property, under civil law, it's called a "conversion" and under criminal law it's a theft. You can sue a person fordamages (that is, money) who has converted your property. The damages would be for the property not returned and for damage to property returned in a damaged state. You would need to prove the fact that the converter took possession of the property and held onto it without your permission, and to prove the value of any property not returned to you or the cost of damage to the property returned in a damaged state. Normally you need purchase receipts, written proof you purchased the property or maybe listings on the web for the same item showing the current purchase price (which will be discounted since the property is no longer new).
Property voluntarily given to a person (called a "bailee") who agrees to hold onto or care for your property for some period of time is called a "bailment." A Bailee is usually required to take ordinary care of the property, but may be required to be more careful if the bailment is paid for.
The term "misappropriation" you mention is usually used in connection with the taking or using of someone's likeness or identity and does not apply in your case.
"Replevin" is the name given under Pennsylvania law to the type of lawsuit a person files in order to get your property returned to you. If the "individual" converted your property, you would file an action in replevin to get it back.
Again, without a better understanding of the background and facts, it's difficult to tell whether this is a criminal matter, a civil matter, or both. If you succeed in a civil action, you will be awarded possession of the property and/or money damages. Criminal actions are not brought by the person harmed, but by the state - and in nearly all cases, the harmed person is not awarded any monies.
Collect any and all paperwork you have, notes, receipts, EVERYTHING about this transaction and the property that is missing. Take them to a lawyer and have him/her go through the facts with you thoroughly. This is rather complicated but a good lawyer should be able to sort it out with all the needed information. Good luck!
The information provided is for general informational purposes only and is not intended to be legal advice. I am only licensed in the Commonwealth of Pennsylvania and I am not providing you with specific legal advice. The law changes frequently and varies from jurisdiction to jurisdiction. Being general in nature, the information provided may not apply to any specific factual and/or legal set of circumstances and/or the jurisdiction where you reside. No attorney-client relationship is formed nor should any such relationship be implied. The information provided is of a general nature is not intended to substitute for the advice of an attorney, especially an attorney licensed in your jurisdiction. Your question, although you may believe is simple, it is not simple. You require legal advice, please consult with a competent attorney licensed to practice in your jurisdiction.