PLF is an enigmatic otologic disease that may be congenital or acquired through surgery, trauma, neoplasm, or infection. The exact incidence of PLF is unknown, primarily because it is difficult to diagnose. A careful, thorough history is important in recognizing PLF. If a PLF exists, repair can be effected simply and quickly and may be very beneficial to the patient. There is a small but real risk of total hearing loss with operation to repair any PLF. Currently, the most useful diagnostic tests for PLF involve the vestibular system, and further studies of vestibular responses to PLF hold promise in improving our diagnostic ability.