Adult obstructive sleep apnea related to nasopharyngeal obstruction: a case of retropharyngeal lipoma and pathogenetic considerations.

Cervico facial lipomas are relatively rare and only a few of them affect retropharyngeal space. Because of their slow growth rate, they can reach large size before causing respiratory disturbances and surgery is the treatment of choice. We present a case of 73-year-old female patient with severe obstructive sleep apnea [Apnea Hypopnea Index (AHI) = 43; mean SaO2 = 84%; lowest SaO2 = 60%; time of sleep with SaO2<90% = 35%]. Computed tomography scan showed a low attenuation bilobed retropharyngeal mass (5 x 2 x 2.5 cm) compatible with lipoma, extending from the nasopharynx to the superior bound of the oropharynx (at the level of C2-C3 passage). Removal of the tumor cured the obstructive sleep apnea; the sleep study at 1 month follow-up showed the normalization of the somnographic parameters (AHI = 12; lowest SaO2 = 76%; mean SaO2 = 95%; time of sleep with SaO2<90% = 4%).