Department of Plastic and Reconstructive Surgery, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Kanazawa-ku, Yokohama, Kanagawa, 236-004, Japan.
Department of Plastic and Reconstructive Surgery, Chigasaki Municipal Hospital, Honson 5-15-1, Chigasaki, Kanagawa, 253-0042, Japan.
J Med Case Rep. 2021 Mar 2;15(1):99. doi: 10.1186/s13256-020-02584-6.
Dermoid cysts are well-known lesions that manifest as subcutaneous tumors around the lateral sides of the eyebrows in young patients. Computed tomography or magnetic resonance imaging (MRI) is often performed to confirm the diagnosis. On the other hand, a lipoma is usually a circular lesion, which is sometimes observed in the upper part of the face. The signals of both T1-weighted and T2-weighted images of MRI of a lipoma are, in general, relatively highly homogenous, and the signals decrease in fat-suppressed images. Therefore, differential diagnosis between a dermoid cyst and a lipoma is usually made with MRI, especially based on fat-suppressed images. Here, we present a case of misdiagnosis of a dermoid cyst as a lipoma because of atypical magnetic resonance images.
We report a case of a 24-year-old Japanese woman with a dermoid cyst around the lateral edge of the eyebrow. The cyst had been gradually increasing in size for the past 2 years. On MRI, it showed high internal signals on T1- and T2-weighted images. However, the signal intensity decreased homogeneously in the fat-suppressed T2-weighted images. The observed tumor had a yellowish appearance under the endoscope. On the basis of these findings, the lesion was considered a lipoma until it ruptured intraoperatively. The pathological diagnosis confirmed it to be a dermoid cyst.
Some dermoid cysts contain lipid-rich liquid, and these may be misdiagnosed as lipomas by MRI. When a tumor is located at a common site for a dermoid cyst, the MRI images should be validated carefully if it appears like a lipoma, and the differential diagnosis should be considered carefully.
皮样囊肿是一种众所周知的病变，表现为年轻患者眉毛外侧的皮下肿瘤。通常进行计算机断层扫描或磁共振成像（MRI）以确认诊断。另一方面，脂肪瘤通常是圆形病变，有时在上部面部观察到。MRI 的 T1 加权和 T2 加权图像的脂肪瘤信号通常相对均匀，并且在脂肪抑制图像中信号降低。因此，皮样囊肿和脂肪瘤之间的鉴别诊断通常通过 MRI 进行，特别是基于脂肪抑制图像。在这里，我们报告了一例由于磁共振成像不典型而误诊为脂肪瘤的皮样囊肿病例。
我们报告了一例 24 岁日本女性，其眉毛外侧有皮样囊肿。过去 2 年来，囊肿的大小逐渐增大。在 MRI 上，T1 和 T2 加权图像上显示内部信号高。然而，脂肪抑制 T2 加权图像上的信号强度均匀降低。在内窥镜下观察到的肿瘤呈黄色外观。基于这些发现，该病变被认为是脂肪瘤，直到术中破裂。病理诊断证实为皮样囊肿。
一些皮样囊肿含有富含脂质的液体，这些液体可能会被 MRI 误诊为脂肪瘤。当肿瘤位于皮样囊肿常见部位时，如果其外观类似于脂肪瘤，则应仔细验证 MRI 图像，并应仔细考虑鉴别诊断。
