A biopsy device includes an elongate inner sheath rotatably coupled to a first drive mechanism. The elongate inner sheath has a side port that opens to a sample chamber in the elongate inner sheath. An elongate outer sheath is rotatably coupled to a second drive mechanism. The elongate outer sheath is coaxial with the elongate inner sheath. The elongate outer sheath includes a side opening having a cutting edge having a lengthwise orientation. The elongate inner sheath is configured for rotation relative to the elongate outer sheath via the first drive mechanism, and the elongate outer sheath is configured for rotation relative to the elongate inner sheath via the second drive mechanism such that the cutting edge passes over the side port to sever tissue.