PURPOSE: To describe the imaging features of chest wall mesenchymal hamartoma with emphasis on cross-sectional imaging and comparison with histopathologic results. MATERIALS AND METHODS: For 14 mesenchymal hamartomas of the chest wall in 12 children, radiologic studies (computed tomographic [CT] scans [n = 14], radiographs [n = 11], magnetic resonance [MR] images [n = 9], and bone scintigraphic images [n = 1]) were reviewed by four radiologists with consensus agreement. Clinical history was reviewed for patient demographics and symptoms at presentation. Radiologic studies were evaluated for lesion location, size, number of affected ribs, cortical irregularity or erosion, presence and type of matrix mineralization, lung hyperaeration adjacent to the lesion, degree and homogeneity of radionuclide uptake, and intrinsic characteristics on CT and MR images. RESULTS: Patients included seven male and five female children. Nine patients (75%) were younger than 1 year. Five patients had a chest wall mass; in the remaining seven, the lesion was discovered incidentally. All 14 lesions arose from ribs, 11 were located posteriorly, and 11 affected multiple contiguous ribs. Two patients had multifocal disease, each with two discrete lesions. Radiography in all cases revealed a large expansile rib lesion and an associated extrapleural soft-tissue mass, suggesting an aggressive process. Mineralization was seen in seven (64%) lesions at radiography and in 14 (100%) lesions at CT. Hemorrhagic cavities (secondary aneurysmal bone cyst [ABC] regions) were common, seen in nine (64%) lesions at CT and in four (80%) of five lesions imaged with T2-weighted MR imaging. CONCLUSION: Mesenchymal hamartoma of the chest wall may be recognized by its characteristic occurrence in infancy and cross-sectional imaging features of mineralization and hemorrhagic cystic (secondary ABC) components.
PURPOSE: To describe the imaging features of chest wall mesenchymal hamartoma with emphasis on cross-sectional imaging and comparison with histopathologic results. MATERIALS AND METHODS: For 14 mesenchymal hamartomas of the chest wall in 12 children, radiologic studies (computed tomographic [CT] scans [n = 14], radiographs [n = 11], magnetic resonance [MR] images [n = 9], and bone scintigraphic images [n = 1]) were reviewed by four radiologists with consensus agreement. Clinical history was reviewed for patient demographics and symptoms at presentation. Radiologic studies were evaluated for lesion location, size, number of affected ribs, cortical irregularity or erosion, presence and type of matrix mineralization, lung hyperaeration adjacent to the lesion, degree and homogeneity of radionuclide uptake, and intrinsic characteristics on CT and MR images. RESULTS:Patients included seven male and five female children. Nine patients (75%) were younger than 1 year. Five patients had a chest wall mass; in the remaining seven, the lesion was discovered incidentally. All 14 lesions arose from ribs, 11 were located posteriorly, and 11 affected multiple contiguous ribs. Two patients had multifocal disease, each with two discrete lesions. Radiography in all cases revealed a large expansile rib lesion and an associated extrapleural soft-tissue mass, suggesting an aggressive process. Mineralization was seen in seven (64%) lesions at radiography and in 14 (100%) lesions at CT. Hemorrhagic cavities (secondary aneurysmal bone cyst [ABC] regions) were common, seen in nine (64%) lesions at CT and in four (80%) of five lesions imaged with T2-weighted MR imaging. CONCLUSION: Mesenchymal hamartoma of the chest wall may be recognized by its characteristic occurrence in infancy and cross-sectional imaging features of mineralization and hemorrhagic cystic (secondary ABC) components.