Abstract

The Rosenmüller Fossa (RF) is the most common site of origin for nasopharyngeal carcinoma (NPC); however, its morphometric characteristics remain underinvestigated in clinical imaging studies. This study aimed to evaluate the morphological and dimensional differences in the RF between patients with NPC and healthy controls using magnetic resonance imaging (MRI). A retrospective analysis of MRI data from 41 patients with NPC and 49 age- and sex-matched controls without nasopharyngeal pathology was performed. Measurements included RF height, width, inter-fossa distance, and nasopharyngeal depth on axial and sagittal MR images. RF morphology was classified as Type A (shallow), Type B (deep and narrow), or Type C (deep and wide). The mean age of patients with NPC was 51.22 ± 13.81 years, and 68.29% were men. Tumor laterality was bilateral in 56.10% of the cases, and RF involvement was observed in 70.73% of the cases. No significant differences were found in right RF dimensions or R-L distance (p>0.05); however, left RF height was significantly reduced in patients with NPC (3.49 vs. 5.42 mm; p=0.013). Nasopharyngeal depth was also shorter in patients with NPC (17.40 mm vs. 19.03 mm; p=0.006). The RF morphology distribution did not differ significantly (p=0.381), although Type C fossae were more common in patients with NPC (26.83% vs. 14.29%). MRI revealed significant reductions in the left RF height and nasopharyngeal depth in patients with NPC, suggesting asymmetrical nasopharyngeal involvement. Detailed RF assessment using MRI may contribute to the early detection and improved staging of NPC.

Key words: Rosenmüller fossa, recessus pharyngealis, nasopharyngeal carcinoma, magnetic resonance imaging