PAPILLARY ENDOLYMPHATIC SAC TUMORS - CT, MR-IMAGING, AND ANGIOGRAPHICFINDINGS IN 20 PATIENTS

PURPOSE: To determine the computed tomographic (CT), magnetic resonanc e (MR) imaging, and angiographic findings of papillary endolymphatic s ac tumors. MATERIALS AND METHODS: Clinical and imaging studies in 20 p atients (aged 17-65 years) with histopathologically proved papillary e ndolymphatic sac tumors were retrospectively reviewed. Patients underw ent CT (n = 18), MR imaging (n = 15), or angiography (n = 12). CT scan s were evaluated for bone erosion and calcification; MR images, for si gnal intensity, enhancement patterns, and flow voids; and angiograms;f or tumoral blood supply. RESULTS: All tumors were destructive and cont ained calcifications centered in the retrolabyrinthine region at CT. T he MR imaging appearance varied with lesion size; 12 of 15 tumors show ed increased signal intensity at T1-weighted imaging. The high-signal- intensity area was circumferential in lesions 3 cm or smaller and was scattered throughout the lesion in advanced tumors. Only tumors larger than 2 cm had flow voids. The blood supply arose predominantly from t he external carotid artery. Large tumors had additional supply from th e internal carotid and posterior circulation. CONCLUSION: Papillary en dolymphatic sac tumors are destructive, hypervascular lesions that ari se from the temporal bone retrolabyrinthine region. Increased signal i ntensity at unenhanced T1-weighted MR imaging is common and may help d istinguish these lesions from more common, aggressive temporal bone tu mors.