Takemura Noriko, Fujii Norikazu, Shibata Chikako, Kawano Akiko, Fujimoto Noriki, Uenishi Toshiaki, Tanaka Toshihiro
Division of Dermatology, Higashi-Ohmi Keiai Hospital, Yokaichi, Higashi-Ohmi, Japan.
J Dermatol. 2007 Mar;34(3):193-7. doi: 10.1111/j.1346-8138.2007.00248.x.
We describe a case of a giant epidermal cyst of the buttock that demonstrated a fluid-fluid level on imaging. There have been no previously reported cases of epidermal cysts containing a fluid-fluid level, so our case was considered to be very exceptional. A 39-year-old man had had a slowly enlarging giant subcutaneous mass in the left buttock for more than 10 years. It was elastic-soft, well-circumscribed and smooth-surfaced. Ultrasonography showed a well-circumscribed hypoechoic mass with a fluid-fluid level in the subcutis of the left buttock. Magnetic resonance imaging (MRI) showed a well-circumscribed cystic mass measuring 8 cm x 5.5 cm x 5.5 cm in the same place that the ultrasonography indicated. It was hypointense on the T1-weighted image, hyperintense on the T2-weighted image, and contained a fluid-fluid level on both the T1- and T2-weighted images. It bordered on the anus, but neither adhered nor formed a fistula with it. A surgical excision was performed. The mass was diagnosed histopathologically as an epidermal cyst. The occurrence of fluid-fluid levels in epidermal cysts should be kept in mind in the differential diagnosis of subcutaneous soft tissue tumors.
我们报告一例臀部巨大表皮样囊肿，其在影像学上表现为液-液平面。此前尚无表皮样囊肿出现液-液平面的报道，因此我们的病例被认为非常罕见。一名39岁男性，左侧臀部有一个缓慢增大的巨大皮下肿物，已持续10余年。肿物质地弹性柔软，边界清晰，表面光滑。超声检查显示左侧臀部皮下有一个边界清晰的低回声肿物，内有液-液平面。磁共振成像（MRI）显示在超声所示相同位置有一个边界清晰的囊性肿物，大小为8 cm×5.5 cm×5.5 cm。在T1加权像上呈低信号，在T2加权像上呈高信号，且在T1加权像和T2加权像上均有液-液平面。肿物毗邻肛门，但未与其粘连或形成瘘管。遂行手术切除。术后病理组织学诊断为表皮样囊肿。在皮下软组织肿瘤的鉴别诊断中，应考虑表皮样囊肿出现液-液平面的情况。
