Gelenkchirurgie, HELIOS ENDO-Klinik Hamburg.
Z Orthop Unfall. 2020 Dec;158(6):618-624. doi: 10.1055/a-0997-6959. Epub 2019 Nov 19.
Soft tissue swelling of the knee joint can be caused by many diseases. Lipomas are one of the most reasonable differential diagnoses we have to consider. Therefore, we now present the uncommon case of a Lipoma arborescens (LA) and differentiate it from a quite similar manifesting spindle cell lipoma as follows.
A 49-years old patient reports about progressive knee pain for four years and observes an increasing joint swelling. This swelling is a soft tissue, shiftable tumour, not painful. The magnetic resonance imaging (MRI) with contrast agent brings the diagnosis of an advanced osteoarthritis of the knee joint and classifies the tumour as LA. Subsequently, we treat the osteoarthritis by implanting a total knee arthroplasty with simultaneous intraoperative tumour resection performed as total synovectomy. The histopathological processing confirms the clinically and radiologically made diagnosis of LA.
Lipoma arborescens presents an uncommon subgroup of Lipomas, which is characterized by a slowly progressive increasing soft tissue swelling, especially around bigger human joints. Due to its intraarticular location, the LA might become clinically relevant when it reaches a certain tumour size. Looking at the diagnostics, sonography, MRI and especially the histopathological processing give the crucial results. Final proof can only be made by histopathological examination. Additionally, we have some differential diagnoses to exclude. Under these we predominantly find the spindle cell lipoma, synovial haemagioma, vascular synovial malformations and tenosynovial giant-cell tumour. Furthermore, an atypical lipomatous tumour should be excluded by FISH-analysis via determining the MDM2-Genamplification.
膝关节软组织肿胀可由多种疾病引起。脂肪瘤是我们最需要考虑的合理鉴别诊断之一。因此，我们现在提出了一个不常见的病例，即树枝状脂肪瘤（LA），并将其与表现相似的梭形细胞脂肪瘤区分开来，如下所述。
一名 49 岁的患者报告说，他的膝关节疼痛已经持续了四年，并观察到关节肿胀逐渐加重。这种肿胀是一种软组织、可移动的肿瘤，无痛。磁共振成像（MRI）和造影剂检查诊断为膝关节晚期骨关节炎，并将肿瘤归类为 LA。随后，我们通过植入全膝关节置换术治疗骨关节炎，同时进行术中肿瘤切除术，作为全滑膜切除术。组织病理学处理证实了临床和放射学上的 LA 诊断。
树枝状脂肪瘤是脂肪瘤的一种不常见亚组，其特征是软组织肿胀缓慢进行性增加，尤其是在较大的人体关节周围。由于其位于关节内，当肿瘤达到一定大小时，LA 可能会变得具有临床相关性。在诊断方面，超声、MRI 尤其是组织病理学处理提供了关键结果。最终的证据只能通过组织病理学检查来确定。此外，我们还有一些需要排除的鉴别诊断。在这些鉴别诊断中，我们主要发现了梭形细胞脂肪瘤、滑膜血管瘤、血管滑膜畸形和腱鞘巨细胞瘤。此外，通过确定 MDM2 基因扩增，还需要通过 FISH 分析排除非典型脂肪肉瘤。
