Is it acceptable to use a microscope in the office and not in the laboratory?
I see three main potential issues in the use of a microscope informally in an office, rather than in a laboratory environment:


Safety: some samples might be potentially hazardous to a person handling them without laboratory protections.
Sample damage: some samples may be vulnerable to contamination or damage through exposure to an office environment.
Ethics: information on a patient or student subject may be exposed through informal handling of a sample.


If all three of these can be dealt with (e.g., through proper sample preparation and reasonable precautions against exposure of adverse information), then I see no reason that a microscope cannot be used in an informal office environment. I am not familiar with precautions around the particular samples you mention in your post, but many fixatives used with specimens are extremely effective and might well render samples quite inert.