RQA GLP Committee
We have assumed that you do mean the Pathologist to be the study director and not the principal investigator.
It would be unusual for a Pathologist to be a Study Director (and therefore have control of the whole study). It would be more usual for them to act as a Principal Investigator for the slide reading process, but if your facility judge that the pathologist has the appropriate scientific background to be the study director, and your SOPs describe how studies work this way, then the GLP regulation does not say that you cannot do this.
Depending how your coding works, it does sound as though this does have the potential to be a conflict of interest. Ensure that everything is clearly documented and controlled to be able to support unbiased reporting if this is what is required. The coding should not be done by the study director.