The invention provides a device 10 for analysis of tissue cells 12 in a living body, the device comprising a stylet 14, the stylet comprising a clad optical fiber senior 18 enveloped in a tubular jacket 20, wherein an unclad area 24 of the fiber and a jacket window 26 corresponding to the unclad area are proximate to the distal end 28 thereof, the optical fiber 18 being linked at a proximate end 30 to receive light from a light source 32, the device further including a light analyzer 34 for measuring qualities of output light at the depth at which the unclad area 24 is positioned in the body during use, an electronic data processor 36 being linked between the light analyzer 34 and a display 38 provided to show real-time data regarding any area 40 evidencing a change in optical properties of body tissues being successively examined.
