CT features and differential diagnosis of benign and malignant thymus diseases in children / 中华放射学杂志

ABSTRACT

Objective:To explore the CT features of benign and malignant thymus diseases in order to improve the diagnostic accuracy of thymus diseases in children.Methods:The clinical data and imaging data of children with thymic diseases who underwent CT examination in children′s Hospital Affiliated to Capital Institute of Pediatrics from August 2014 to may 2019 were retrospectively analyzed. There were 32 males and 18 females with an average age of (6±4) years (range 5 days to 14.2 years). According to the clinical diagnosis and/or pathological results, all children were divided into benign group (22 cases) and malignant group (28 cases). The clinical manifestations and CT signs (thymus volume, shape, border, density, internal characteristics, relationship with surrounding structures, enhancement pattern and extent) of benign group and malignant group were summarized and compared.Results:The clinical manifestations of benign group and malignant group were varied, and fever was the most common sign. In the benign group, 8 cases showed thymus deficiency, all of them were diagnosed as primary immunodeficiency disease, and the clinical manifestations were repeated and persistent respiratory tract infection history. In 28 cases of malignant group, 20 cases had peripheral invasion and distant metastasis, including 7 cases of lymph node, 6 cases of pleura, 6 cases of lung, 2 cases of pericardium, 2 cases of liver, 2 cases of spleen, 2 cases of kidney and 1 case of bone. All 6 cases of pleural involvement occurred in children with non Hodgkin′s lymphoma. There were significant differences in CT findings between the two groups ( P<0.05); there were no significant differences in terms of shape, density, internal calcification or cystic change, enhancement pattern and enhancement extent of thymus lesions between the two groups ( P>0.05). Conclusions:Benign lesions of thymus usually manifests as absence or normal size of thymus, well-defined, non-necrotic, no displacement of vessels, no peripheral or distant invasion on CT; whereas malignant lesions are mostly enlarged, well or ill-defined, with internal necrosis and vessel displacement, surrounding or distant invasion. CT manifestations of benign and malignant thymus diseases have featured characteristics, and the combination of clinical manifestations is helpful for the differential diagnosis.