Usefulness of the 'cosmos pattern' for differentiating between cervical gastric-type mucin-positive lesions and other benign cervical cystic lesions in magnetic resonance images.

ABSTRACT

AIM: To evaluate the usefulness of the 'cosmos pattern' (CP) on magnetic resonance (MR) images for differentiating between gastric-type mucin-positive lesions (GMPL) and gastric-type mucin-negative lesions (GMNL). METHODS: This study included 131 patients with clinical suspicion of lobular endocervical glandular hyperplasia (LEGH) who underwent pelvic MR imaging and a Pap smear and/or latex agglutination assay. Differences in MR findings, such as cyst and solid component patterns, cervical location and T1-weighted image (T1WI) signal intensity, were compared between GMPL and GMNL. The diagnostic performances of the findings were assessed. RESULTS: The frequencies of CP (63.1%), upper part (UP) lesions (72.3%) and hypointense area compared with the cervical stroma on T1WI (61.3%) were significantly greater in GMPL than in GMNL (P < 0.05). The sensitivity, specificity, positive predictive value, negative predictive value and odds ratio of the CP for diagnosis of GMPL were 63.1%, 87.9%, 83.7%, 70.7% and 12.4, respectively. In GMNL, a 'macrocystic pattern' was observed in 65.2% of patients; an isointense or hyperintense area on T1WI was observed in 86.4% of patients. The sensitivity was highest (90.8%) when one or more of the following were observed CP, UP lesion, or hypointense area on T1WI. The specificity was highest (95.5%) when the CP was observed as a hypointense area on T1WI. CONCLUSION: The CP is a highly specific finding for diagnosis of GMPL. If the CP is observed as a hypointense area compared with the cervical stroma on T1WI, GMPL (i.e., LEGH or gastric-type mucinous carcinoma) should be strongly suspected.