Cho Myung Rae, Jun Chung Mu, Oh Tae Bum, Kwon Jae Bum, Choi Won Kee
Department of Orthopaedic Surgery, College of Medicine, Daegu Catholic University, Daegu City, Republic of Korea.
Medicine (Baltimore). 2019 Jul;98(27):e16322. doi: 10.1097/MD.0000000000016322.
Cases of pseudotumor complicated after THA with metal-on-metal articulation as a bearing surface have been reported. Most of the pseudotumors occurred near or inside the hip joint, and usually have similar features with the infectious condition. We herein report a case of pseudotumor with huge size in the pelvic cavity mimicking features of iliacus muscle abscess.
A 70-year-old female was referred to our emergency department due to huge mass in her right pelvic area on abdominal CT. She complained of mild febrile sensation, generalized weakness, and pain in her right leg for several months. The patient underwent metal-on-metal bearing THA 11 years ago for treatment of right-sided hip pain due to avascular necrosis.
Percutaneous catheter drainage was performed for both therapeutic and diagnostic reasons. No microbes were cultured from the drained fluid, and signs of chronic inflammation were shown on pathology slide samples. The patient showed positive allergic reactions to cobalt and captan on allergic patch test, and serum cobalt levels was increased as 46.78 μg/L (normal value, 0.11-0.64 μg/L). Biopsy samples of the cyst were consistent with the histological findings of pseudotumor reported by Willert et al. INTERVENTION:: For the treatment of infection, primarily, the patient was surgically treated by irrigation, debridement, and bone bead insertion. Then, after 4 weeks of antibiotic treatment, revision surgery changing the metal-on-metal articulation into poly-on-metal articulation was performed.
CT scan at 1 year after surgery showed no findings of cyst inside the pelvic cavity. Although the patient complained of right sided hip pain (VAS score 2), she was able to perform activities of daily living.
In patients who underwent metal-on-metal THA, pseudotumor mimicked the feature of periprosthetic infection may occur not only inside the hip joint but also in the pelvic cavity.
有报道称，以金属对金属关节作为承重表面的全髋关节置换术（THA）后出现了假体周围假瘤病例。大多数假瘤发生在髋关节附近或内部，通常具有与感染情况相似的特征。我们在此报告一例盆腔内巨大假瘤的病例，其表现类似髂肌脓肿。
一名70岁女性因腹部CT显示右盆腔巨大肿块被转诊至我院急诊科。她主诉数月来有轻微发热感、全身无力及右腿疼痛。该患者11年前因右侧股骨头缺血性坏死导致的髋关节疼痛接受了金属对金属承重表面的THA手术。
出于治疗和诊断目的进行了经皮导管引流。引流液中未培养出微生物，病理切片样本显示有慢性炎症迹象。患者在过敏斑贴试验中对钴和克菌丹呈阳性过敏反应，血清钴水平升高至46.78μg/L（正常值为0.11 - 0.64μg/L）。囊肿的活检样本与Willert等人报道的假瘤组织学结果一致。
对于感染的治疗，首先对患者进行了冲洗、清创和骨珠植入的手术治疗。然后，在抗生素治疗4周后，进行了翻修手术，将金属对金属关节置换为聚乙烯对金属关节。
术后1年的CT扫描显示盆腔内无囊肿迹象。尽管患者仍主诉右侧髋关节疼痛（视觉模拟评分2分），但她能够进行日常生活活动。
在接受金属对金属THA的患者中，模拟假体周围感染特征的假瘤不仅可能出现在髋关节内，也可能出现在盆腔内。
