Why do diseases have such odd and hard to say names like Dupuytren disease or schwanomas?

Many diseases and syndromes are named after the doctor or scientist that either first identified it or first documented it in medical literature. Since anyone could be in that position, some of the names are from doctors who have difficult to spell or say names. Many times, some diseases don't have a person's name attached but this happens over the course of time. For example, amyotrophic lateral sclerosis (ALS) is often called Lou Gehrig's disease.

Other problems, such as schwannomas are also indirectly named after people. A schwannoma is a tumor that comes from a cell called a Schwann cell. This cell, discovered by the researcher Theodore Schwann helps protect the nerve cells. So, when researchers discovered that there were tumors that could come from this cell, they chose to call them schwannomas.