Fine-needle biopsy.

Local injury of seminiferous tubules caused by fine-needle biopsies in humans does not cause testicular inflammation (orchitis).

Consequently, half of these patients had no evidence of MTC on fine-needle biopsy and thus might not have undergone surgery without the positive calcitonin stimulation test.

The needle used in this procedure is slightly larger than the one used for a fine-needle biopsy because the procedure is intended to remove a small cylinder of tissue that will be sent to the laboratory for further examination.