Abstract
This report describes the treatment of a frontal sinus cyst in a patient who suffered long-term exposure to nitric acid. The 66-year-old male patient had no history of nasal surgery. He was employed at a stainless steel processing facility for 50 years in a position requiring the use of high-temperature, highly concentrated nitric acid during scale cleaning of welded metal. During this time (mid-1960s to mid-1970s), protective masks were not generally worn, and the patient was thus exposed to vaporized nitric acid and its by-product, nitrogen oxide, for a
prolonged period. In mid-January 2013, he was examined by a local physician for a chief complaint of swelling around the left eye. A frontal sinus cyst was identified on a cranial MRI, and the patient was referred to our facility for
examination. The imaging suggested a possible retention cyst, and while no visual or ocular motility impairment was found on initial examination, surgery was recommend at the earliest opportunity to treat the partial bone erosion. That same month, a left frontal sinus endoscopic frontal sinusotomy (Draf IIb) was performed. The surgery opened up the left frontal sinus cyst but did not alleviate the left upper eyelid swelling. In addition, we performed a skin incision for eyelid skin, which only resulted in the spread of a small volume of pus. There were no subsequent complications, and the patient was discharged 3 days postoperatively. The swelling at
the upper left eyelid resolved approximately 1 week after discharge from the hospital and was attributed to spreading inflammation from the cyst. The patient recovered well and is currently receiving outpatient
follow-up examinations. There are no known reports to date describing a causative relationship between nitric acid exposure and the development of frontal sinus cysts or nasal septum perforation. However, nitric acid and nitrogen oxide are known to damage the mucous membranes. This patient had no history of nasal surgery, which suggests that the long-term exposure to nitric acid may have caused the frontal sinus cyst and nasal septum perforation.
