Benign Symmetric Lipomatosis Complicated by Severe Obstructive Sleep Apnea During Long-Term Follow-Up: A Case Report.

Benign symmetric lipomatosis (BSL), also known as Madelung disease, is a rare disorder characterized by symmetric and diffuse deposition of nonencapsulated adipose tissue, predominantly in the neck, shoulders, and upper trunk. Although BSL is often recognized as a slowly progressive cosmetic condition, deep cervical and upper airway involvement may cause clinically significant functional impairment. We report a case of BSL that was reevaluated after referral from a prosthodontic clinic and later complicated by severe obstructive sleep apnea (OSA) during long-term follow-up. An 80-year-old man was referred to our department in 2007 after visiting the prosthodontic clinic because of the detachment of dental prostheses. He had noticed cervical swelling since approximately 1983 and had a history of heavy alcohol consumption and alcoholic hepatitis. Clinical examination and imaging showed symmetric, soft, painless fatty masses in the anterior and posterior neck and bilateral shoulder regions, and BSL was clinically diagnosed. The patient discontinued follow-up but returned in 2015 because of enlargement of the cervical masses, snoring, dyspnea during sleep, daytime sleepiness, and hoarseness. Imaging demonstrated progression of cervical fatty deposition with airway narrowing. Polysomnography revealed severe OSA, with an apnea-hypopnea index of 51.7 events/hour, a 3% oxygen desaturation index of 56.6 events/hour, and a lowest peripheral oxygen saturation of 82%. Nasal continuous positive airway pressure therapy was introduced. Because of the patient's advanced age, the nonencapsulated nature of the lesions, the difficulty of complete resection, and the risks of recurrence and deep bleeding, surgical intervention was not performed. A maternal history of similar cervical swelling prompted screening for representative mitochondrial DNA variants, but no mutations were detected. The patient died of presumed cardiac causes approximately one and a half years later. This case highlights that BSL may progress over decades and cause severe sleep-disordered breathing. Dental and oral surgery clinicians should recognize symmetric cervical swelling as a potential manifestation of BSL and consider airway evaluation when snoring, dyspnea, or daytime sleepiness is present.