Abstract: A skin cutter instrument for excising ellipsoid-shaped samples of skin from a patient is disclosed. The skin cutter has a hollow tube, a spring and rod combination within the tube, an assembly with multiple pivotable joints, and two skin cutting blades. The assembly carries out a scissoring motion when the rod is pressed down, causing the blades to come together and thereby remove the skin sample. The blades can have either concave cutting surfaces, or straight cutting surfaces that are deformed into an arc shape. Either blade cutting surface configuration allows for excision of the desired ellipsoid-shaped tissue sample from the patient.