Purpose

Solitary fibrous tumor (SFT) of the orbit is a rare tumor that was first described in 1994. We aimed to investigate its imaging characteristics that may facilitate the differential diagnosis between SFT and other types of orbital tumors.

Material and Methods

Magnetic resonance imaging (MRI) data of patients with immunohistochemically confirmed orbital SFT from 2002 to 2022 at a tertiary care center were retrospectively analyzed. Tumor location, size, morphological characteristics, and contrast enhancement features were evaluated.

Results

Of the 18 eligible patients 10 were female (56%) with a mean age of 52 years. Most of the SFTs were oval-shaped (67%) with a sharp margin (83%). The most frequent locations were the laterocranial quadrant (44%), the extraconal space (67%) and the dorsal half of the orbit (67%). A flow void phenomenon was observed in nearly all cases (94%). On the T1-weighted imaging, tumor signal intensity (SI) was significantly lower than that of the retrobulbar fat and appeared predominantly equivalent (82%) to the temporomesial brain cortex, while on T2-weighted imaging its SI remained equivalent (50%) or slightly hyperintense to that of brain cortex. More than half of the lesions showed a homogeneous contrast enhancement pattern with a median SI increase of 2.2-fold compared to baseline precontrast imaging.

Conclusion

The SFT represents a rare orbital tumor with several characteristic imaging features. It was mostly oval-shaped with a sharp margin and frequently localized in the extraconal space and dorsal half of the orbit. Flow voids indicating hypervascularization were the most common findings.

中文翻译：

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眼眶孤立性纤维性肿瘤的MR成像特征

目的

眼眶孤立性纤维瘤（SFT）是一种罕见的肿瘤，于1994年首次被描述。我们的目的是研究其影像学特征，以促进SFT与其他类型眼眶肿瘤的鉴别诊断。

材料与方法

回顾性分析了 2002 年至 2022 年三级医疗中心经免疫组织化学证实的眼眶 SFT 患者的磁共振成像 (MRI) 数据。评估肿瘤位置、大小、形态特征和对比增强特征。

结果

在 18 名符合条件的患者中，有 10 名是女性（56%），平均年龄 52 岁。大多数 SFT 为椭圆形 (67%)，边缘尖锐 (83%)。最常见的位置是颅后象限（44%）、锥外空间（67%）和眼眶背半部（67%）。几乎在所有情况下（94%）都观察到了流空现象。在 T1 加权成像上，肿瘤信号强度 (SI) 显着低于球后脂肪，并且主要与颞内侧脑皮质相当（82%），而在 T2 加权成像上，其 SI 保持相当（50%）或略高于大脑皮层的信号。超过一半的病灶表现出均匀的对比增强模式，与基线对比前成像相比，中位 SI 增加了 2.2 倍。

结论

SFT 是一种罕见的眼眶肿瘤，具有多种特征性影像学特征。它大多呈椭圆形，边缘尖锐，经常位于锥外空间和眼眶背半部。最常见的发现是表明血管过度形成的流空。