superspecialist
noun
su·per·spe·cial·ist ˌsü-pər-ˈspe-sh(ə-)list 
plural superspecialists
: a specialist concentrating or practicing in a narrow range of a specialty
was sent to a superspecialist for her rare heart condition
superspecialization
ˌsü-pər-ˌspe-sh(ə-)lə-ˈzā-shən
noun plural superspecializations
surgical superspecialization
superspecialized
ˌsü-pər-ˈspe-shə-ˌlīzd
adjective superspecialized care
superspecialized research
Word History
First Known Use
1900, in the meaning defined above