AFAIK these two are independent of each other. Let me try to explain it -
Geographical location is divided into MBMS service areas and each cell of eNodeB (in case of multicell) can belong to one MBSFN area. MBSFN synchronization area is a geographical location under which all the cells belong to same MBFSN area are tightly time synchronized and all of them transmit same content over the same radio resource i.e. time and frequency both by using same MCS. The UE which has subscribed for the session can receive the same data from two different cells without causing any problem since all the cell belong to same MBSFN are tightly synchronized.
