These are easy if your pathology department allows access to anonymized laboratory records.
If you want something realistic, short, and likely to get completed, choose one of these:
“A cross-sectional study of [knowledge/pattern/prevalence] of [condition/test] among [study population] at [institution].”
“A cross-sectional study of hepatitis B vaccination status and awareness among undergraduate medical students.”
Before finalizing a topic, confirm that it has: a clear population, readily available data, a faculty guide, and an ethics-committee pathway if patient records or questionnaires are involved. Questionnaire studies and anonymized retrospective laboratory-record studies are usually most feasible for early undergraduate projects. Studies of virtual microscopy and student-created pathology learning modules have also been used successfully in undergraduate settings, as described in this
virtual microscopy study and this
pathology e-module study.