Tumors in the tracheobronchial tree: CT and FDG PET features.
A variety of tumors, including primary malignant tumors, secondary malignant tumors, and benign tumors, can occur in the tracheobronchial tree. Primary malignant tumors commonly originate from the surface epithelium or the salivary glands, whereas most benign tumors arise from the mesenchymal tissue. At computed tomography (CT), primary malignant tumors manifest as a polypoid lesion, a focal sessile lesion, eccentric narrowing of the airway lumen, or circumferential wall thickening. At fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET), most squamous cell carcinomas show high uptake, whereas adenoid cystic carcinoma and mucoepidermoid carcinoma show variable uptake depending on the grade of differentiation. High-grade malignancies tend to show high and homogeneous uptake. Carcinoid tumors commonly show intense enhancement at contrast material-enhanced CT, which can be helpful in making the diagnosis, and usually have lower uptake at FDG PET than would be expected for a malignant tumor. Secondary malignant tumors occur as a result of either hematogenous metastasis or direct invasion by a malignancy from an adjacent structure. Their CT manifestations are similar to those of primary malignant tumors, with uptake at FDG PET depending primarily on the metabolic activity and degree of differentiation of the primary tumor. Among the benign tumors, hamartoma and lipoma can show characteristic CT findings such as "popcorn" calcification or internal fat. However, CT findings in most benign tumors are nonspecific. At FDG PET, benign tumors usually show little or no uptake and can be differentiated from malignant tumors. Knowledge of the characteristic CT and FDG PET findings of tracheobronchial tumors can aid in diagnosis and treatment planning.
Park
Chang Min
CM
Department of Radiology, Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea.
Goo
Jin Mo
JM
Lee
Hyun Ju
HJ
Kim
Min A
MA
Lee
Chang Hyun
CH
Kang
Mi-Jin
MJ
D000328:Adult; D000368:Aged; D001984:Bronchial Neoplasms / Q000175:diagnosis*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014134:Tracheal Neoplasms / Q000175:diagnosis*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18