Hu Yan, Kuang Bin, Chen Yue, Shu Jian
Department of Radiology Department of Nuclear Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China.
Medicine (Baltimore). 2017 Jun;96(26):e7383. doi: 10.1097/MD.0000000000007383.
The tenosynovial giant cell tumor (TGCT) is a benign but locally aggressive tumor that arises from the synovial membrane of joints, tendon sheaths, and bursae. Although any joint can be affected, involvement of the temporomandibular joint (TMJ) was reported very rarely, and there is no relevant report on F-FDG PET/computerized tomography (CT).
We present here a rare case of diffuse-type of TGCT (D-TGCT) arising from the right TMJ in a 74-year-old woman. The patient was discovered a mass of the right temporal fossa during a head CT scan. However, she did not receive any treatment and was discharged from the hospital. She visited our institution again after 4 years with worsening headache and swelling of the right preauricular area. An enhanced CT demonstrated a 6.0 × 3.4 × 5.0 cm mass of mixed density involving the right TMJ, with evident enhancement and extensive erosion of adjacent bones. Magnetic resonance imaging (MRI) showed hypointensity in the solid part of the mass but high signal intensity in the cystic part or necrosis on T2-weighted images (T2WI). In F-FDG PET/CT images, the solid portion of the mass had increased FDG uptake with a SUVmax of 19.8. It was then diagnosed as D-TGCT by postoperative pathology.
The case report shows the imaging features of the TGCT, including CT, MRI, and F-FDG PET/CT, especially the typical hypointensity on T2WI. Careful preoperative examination and complete resection are the factors that lead to the optimal treatment of the TGCT.
腱鞘巨细胞瘤（TGCT）是一种良性但具有局部侵袭性的肿瘤，起源于关节、腱鞘和滑囊的滑膜。虽然任何关节都可能受累，但颞下颌关节（TMJ）受累的报道非常罕见，且尚无关于F-FDG PET/计算机断层扫描（CT）的相关报道。
我们在此报告一例罕见的弥漫型TGCT（D-TGCT），发生于一名74岁女性的右侧颞下颌关节。患者在头部CT扫描时发现右侧颞窝有一肿块。然而，她未接受任何治疗并出院。4年后，她因头痛加重和右耳前区肿胀再次就诊于我院。增强CT显示一个6.0×3.4×5.0 cm的混合密度肿块累及右侧颞下颌关节，有明显强化且相邻骨质广泛侵蚀。磁共振成像（MRI）显示肿块实性部分在T2加权像（T2WI）上呈低信号，囊性部分或坏死区呈高信号。在F-FDG PET/CT图像中，肿块实性部分FDG摄取增加，SUVmax为19.8。术后病理诊断为D-TGCT。
该病例报告展示了TGCT的影像学特征，包括CT、MRI和F-FDG PET/CT，尤其是T2WI上典型的低信号。术前仔细检查和完整切除是实现TGCT最佳治疗的因素。
