Papillary endobronchial squamous cell carcinoma.

A case of papillary endobronchial squamous cell carcinoma incidentally discovered on routine imaging studies is described. The patient, a 75-year-old woman, underwent imaging studies as part of a standard evaluation for a fracture on the right side of the hip. Chest radiographs were unremarkable other than for a nodular opacity overlying the left hemidiaphragm. Computed tomography of the chest, however, demonstrated an elongated, irregular mass in the right lower lobe that appeared to be associated with an adjacent segmental right lower lobe bronchus. Endoscopy followed by surgical resection was undertaken, revealing a tan, soft mass measuring 1.5 x 1.3 x 0.8 cm that was confined to the bronchus and did not appear to extend into the surrounding lung parenchyma. Microscopically, the mass showed a papillary, superficial squamous cell carcinoma confined to the bronchial mucosa without invasion of adjacent structures. The pathological and imaging features of this unusual variant of bronchogenic carcinoma are reviewed as well as the radiological differential diagnosis of endobronchial lesions. To our knowledge, this is the first report that describes the computed tomographic features of this rare lesion.