Abstract
BackgroundPrimary tracheobronchial granular cell tumors (GCTs) are rare. The characteristics of these tumors are unclear, and they are easily misdiagnosed. Thus, the present study aimed to investigate the clinicopathological features and immunophenotype profile of these tumors of the tracheobronchial tree.MethodsFour patients were treated for GCTs of the tracheobronchial tree at our institution during 2009–2020. The clinicopathologic and immunohistochemical (IHC) findings were performed in all cases. In addition, seven typical GCTs involving the subcutaneous tissues (4/7) and esophagus (3/7) were also selected as control groups to evaluate the differences in IHC characteristics in different locations. Fisher’s exact test was adopted in analysis of categorical data.ResultsThere were four patients, two females and two males, aged 15, 22, 45 and 52. Three tracheobronchial tumors were solitary with a range from 2.0 to 3.1 cm (mean, 2.6 cm) in its large axis, while one sample was multiple. Chest computed tomography (CT) often suggested lung infectious lesions. On histopathology, three samples were typical GCTs, and the other sample was atypical with a fusiform or spindled morphology. All tumor cells stained positive for S100 protein, CD68, and Nestin and negative for Inhibin-α and thyroid transcription factor-1(TTF-1). The Ki-67 index was less than 5%. Tracheobronchial GCTs exhibited occasional focal and weakly positive transcription factor E3 (TFE3) staining and had a lower ratio than those in other sites, while calretinin showed predominant subcutaneous expression. Two patients treated with tumor resection and the others only performed an endoscopic biopsy. Follow-up period ranged from 24 to 68 months with a mean of 42 months.ConclusionsPrimary tracheobronchial GCTs are rare and are often mimics pneumonia, which have a good prognosis even without surgical resections. Tracheobronchial GCTs had an unusual immunophenotype of TFE3 expression compared with other sites. This result may reflect a site-specific phenomenon distinguishing GCTs of the tracheobronchial tree.