A Comparative Study of Calcified Epithelioma of Malherbe And Epidermoid Cyst With Ultrasound

Abstract

Objective: To explore the ultrasonic(US)features of calcified epithelioma Malherbe (CEM) and epidermoid cyst(EC) in differential diagnosis and improve the accuracy of US diagnosis of CEM.Materials and Methods: We retrospectively analyzed 309 subjects, who underwent US examination before operation and pathological diagnosis for CEM or EC post-operation. The subjects were categorized into the training and validation sets according to different inspection times. The US and clinical features of CEM were evaluated through univariate analysis. A multivariate logistic regression model was used to establish the diagnostic model. Results: Statistically significant variables in univariate analysis(P<0.05)were included in the multivariate logistic regression model. The results demonstrated that the diagnostic model for CEM was statistically significant (P<0.001). The risk factors included posterior echo attenuation and hypoechoic halos (OR=9.277, 10.254) and the protective factors included age, thickness diameter, and posterior echo enhancement (OR=0.936, 0.302, 0.156). The diagnostic models tested in the training set (AUC=0.974, 95% CI=0.955-0.994) and the validation set(AUC=0.967, 95% CI=0.926-1.000) demonstrated good discriminant ability.Conclusions: The diagnostic accuracy for CEM is higher compared to EC when the nodule is characterized by posterior echo attenuation, hypoechoic halos, smaller thickness, and younger age. US diagnostic model can guide the diagnosis of CEM.

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

“…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.…”

“…Of the hypoechoic rim, we used the criterion from the Type 2 in the study by Pelizzari et al 5 Only five pilomatricomas were found to have a hypoechoic rim (7.9%, 5/63), while there were nine epidermoid cysts with a hypoechoic rim (11.8%, 9/76) in our study, as shown in Figures 4 and 7. Therefore, the presence of a hypoechoic rim is not a unique diagnostic factor for pilomatricoma, which differs from the findings of Choo et al 6 and Wei et al 21 The reason for this discrepancy may be the variation in inter-reader agreement for identifying a hypoechoic rim.…”

“…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.…”

“…Therefore, the presence of a hypoechoic rim is not a unique diagnostic factor for pilomatricoma, which differs from the findings of Choo et al 6 . and Wei et al 21 . The reason for this discrepancy may be the variation in inter‐reader agreement for identifying a hypoechoic rim.…”

“…These findings are consistent with previous studies. [4][5][6][7][8][21][22][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.…”