Langerhans' cell histiocytosis - A rare cause of sudden onset unilateral sensorineural hearing loss

Langerhans' cell histiocytosis is a rare disorder of unknown aetiology in w hich pathological Langerhans' cells accumulate and destroy local tissue. We report a 38-year-old female who presented with a sudden onset of left sens orineural hearing loss. Magnetic resonance imaging (MRI) revealed a contras t-enhancing lesion in the left mastoid and a second lesion in the hypothala mus. Following left mastoid exploration and biopsy a definitive diagnosis o f Langerhans' cell histiocytosis was made and the patient was treated with external beam radiotherapy. Subsequent right femur and right mastoid involv ement were successfully treated with steroids and cytotoxic chemotherapy. A t one year follow-up the patient had residual left-sided sensorineural hear ing loss with normal hearing in the right ear. To our knowledge, Langerhans ' cell histiocytosis has not been previously reported as a cause of unilate ral sudden onset sensorineural hearing loss. It should be considered in the differential diagnosis of this condition.