An imaging apparatus is provided for imaging tissue samples substantially beneath the surface of the tissue sample. The apparatus includes an objective lens and a window defining a tissue contacting surface in pressure contacting relationship with the surface of the tissue sample when the tissue sample is imaged by the objective lens to view tissue structures for pathological applications. The objective lens focuses an illumination beam through the window to the tissue sample and receives returned reflected light of the beam representative of one or more sections of the tissue sample. The apparatus enables a method for in vivo observation of tissue for diagnosis of conditions substantially beneath the surface of the tissue sample. Both two and three-dimensional imaging may be provided for diagnosis and location of basal cell carcinomas and melanomas, and so as to enable visualization of tumor borders prior to excision.