Effects of inflammation on the accuracy of ultrasound diagnosis of epidermoid cysts

Abstract

Aims: Ultrasound (US) findings of epidermoid cyst (EC) are complex and diverse. Cases of misdiagnoses are high when EC is accompanied by inflammation. The aim of this study was to analyze the features of US diagnosis of EC with inflammation and explore the characteristic images which can improve the accuracy of ultrasound diagnosis.Material and methods: A total of 241 cases were included and retrospectively analyzed. Complete clinical data of all cases were available. Lesions were examined by US before operation and the diagnosis was confirmed by histopathological examination. Based on pathological results ECs with/without acute and chronic inflammation and/or granuloma, all cases were divided into two groups: inflammation and non-inflammation group. The difference of clinical data and US features between groups was analyzed by univariate and multivariate logistic regression.Results: Analysis of skin color, length/thickness, shape, boundary, CDFI and US diagnosis accuracy showed statistical differences between the two groups (p<0.05). Multivariate logistic regression model showed that indistinct boundaries and color Doppler signal were more frequent than those in ECs without inflammation (OR=4.72, 5.89, p<0.05).Conclusion: Indistinct boundaries and color Doppler signal are important features for US diagnosis of EC with inflammation, which can help in improving the accuracy of diagnosis

Integrating vascularity into the pattern classification of pilomatricomas on ultrasound provides a more competent approach for discriminative evaluation

“…These findings are consistent with previous studies 4–8,21–23 . Vascularity is typically absent in epidermoid cysts unless there is coexisting inflammation, while it is rich in dermatofibrosarcomas protuberans and frequently present in pilomatricomas 20,22,23 . In our study, two epidermoid cysts were mistaken as pilomatricoma and inflammatory lesions.…”

“…19 However, typical epidermoid cysts with uncommon features may be mistaken for other lesions. 20,21 In our study, there were five epidermoid cysts with the fistula sign or submarine sign and one epidermoid cyst with an ambiguous onion sign, and these features did not appear in pilomatricomas and dermatofibrosarcomas protuberans.…”

“…Magnetic resonance imaging (MRI) has high resolution in soft tissues, and it is often used for the diagnosis of skin focal lesions, such as the identification of dermatofibrosarcoma protuberans, but it is hard to make a reliable diagnosis of pilomatricoma, 17,18 Typical epidermoid cysts with unique features such as the fistula sign or submarine sign and onion sign can be confidently diagnosed using HFUS examination 19 . However, typical epidermoid cysts with uncommon features may be mistaken for other lesions 20,21 . In our study, there were five epidermoid cysts with the fistula sign or submarine sign and one epidermoid cyst with an ambiguous onion sign, and these features did not appear in pilomatricomas and dermatofibrosarcomas protuberans.…”