Magnetic resonance imaging features of axillary schwannomas in five cases / 中国医师进修杂志

ABSTRACT

Objective To investigate the magnetic resonance imaging (MRI) features and differential diagnosis of axillary schwannomas, and analyze the causes of misdiagnosis. Methods A retrospective study from October 2014 to October 2017 was performed in 5 patients with axillary schwannomas, confirmed by surgery and pathology, in whom clinically suspected axillary metastases have been diagnosed. All the patients underwent breast MRI to summarize the key points of diagnosis and differential diagnosis. Results Five tumors located in neurovascular bundles extending along the brachial plexus nerve distribution. The tumors presented as single, spindle or ovoid masses, well-circumscribed margins in 4 cases, entering and exiting nerve signs in 5 cases, the split fat sign in 4 cases, vascular compressed sign in 5 cases, and target sign in 1 case. The tumors were isointense or slight hypointense on T1WI compared to the adjacent muscle. Three tumors manifested heterogeneous slight hyperintense, 1 tumor was slight hyperintense, and the target sign was seen in 1 tumor on T2WI. Diffusion-weighted image was heterogeneous hyper or slightly hyper-intense. When b＝500 and 1 000 s/mm2, the apparent diffusion coefficient (ADC) was (1.40 - 2.23) × 10 -3mm2/s and (1.31 -2.94) × 10-3mm2/s respectively. All the 5 tumors manifested persistent enhancement on dynamic contrast-enhanced MRI (DCE-MRI). Three tumors were heterogeneously enhanced, and 2 tumors were circularly enhanced. Conclusions Axillary schwannomas has certain characteristics which can be helpful for the identification of metastatic lymph nodes.