A medical device for collecting cells includes a rotatable drive wire having a proximal portion, a distal portion, an offset portion of the distal portion, and a head member attached to the offset portion. The drive wire is coupled to an axially translatable rack member via a rotation mechanism that converts axial translation of the rack member into rotation of the drive wire. The offset portion of the drive will rotate eccentrically relative to the longitudinal axis of the drive wire to increase the diameter of the rotation of the head portion. The head portion can contact an inner surface of the body cavity to collect cells, and the eccentric rotation of the head member can limit trauma experienced by the patient relative to traditional scraping of a cell collection brush.