CT Evaluation of Rosenmüller Fossa Types in Nasopharyngeal Carcinoma: A Retrospective Study

Abstract

Aims: This study aimed to characterize the morphological variations of the Rosenmüller fossa (RF) in patients with nasopharyngeal carcinoma (NPC) using computed tomography (CT) imag-ing and to identify radiological patterns associated with the presence of the disease, rather than investigating etiological predisposition. Materials and Methods: A total of 74 CT images of histopathologically confirmed NPC cases and 74 age and sex-matched controls without NPC were retrospectively evaluated. To minimize observer bias, RF types were classified by two blinded observers. Statistical analyses were per-formed using the Fisher-Freeman-Halton test for categorical variables with small sample sizes and the Wilcoxon Signed Rank test, with a significance level set at p < 0.05. Results: Among NPC patients, Type 1 RF (shallow/obliterated) was the most common morphol-ogy. A statistically significant difference was observed in the distribution of RF types between the right and left sides (p = 0.038), with the 'Not Assessable' category being markedly more frequent on the right side. Regarding sex, a significant difference in RF type distribution was found on the left side (p = 0.03), whereas no significant difference was observed on the right side (p > 0.05). RF type distribution differed significantly between NPC patients and age- and sex-matched con-trols on both sides (p < 0.001). Conclusion: Although specific RF morphological alterations, particularly obliteration, were frequently observed in NPC patients, these likely represent secondary changes due to tumor infiltration rather than congenital risk factors. Nevertheless, recognizing these patterns on CT is crucial for diagnostic accuracy. Radiologists and clinicians should be vigilant for RF asymmetry as a key indicator for early referral and diagnosis.