Clinicopathological characteristics and gene analysis of pulmonary granular cell tumor in three cases and a systematic review

BACKGROUND: Pulmonary granular cell tumor (PGCT) is a rare neoplastic disease. We assessed the clinicopathological characteristics and gene analysis of PGCT with a systematic review of literature. METHODS: We studied the clinical presentation, radiological image, pathological features, treatment option and follow-up of three cases of PGCT, in whom two had next generation sequencing (NGS) performed for identification of genetic mutation. We also systematically analyzed 78 cases from the literature that met inclusion criteria. RESULTS: Three cases of PGCT (two benign cases and one malignant case) with clinical, radiological, pathological and therapeutic information are presented. There were 81 cases in total enrolled in this study for review. PGCT occurred predominantly in women (63.0%). Fifty-five patients (67.9%) were symptomatic with cough, dyspnea and chest pain being the most common symptoms. The bronchus was the most common site of PGCT (46.9%). The majority of patients were benign PGCT, apart from seven patients with malignant PGCT (8.6%). Forty-one patients received surgical treatment, 12 received bronchoscopic treatment and 28 patients had no relevant information. Forty-two patients had no recurrence at the end of follow-up, 7 patients had residual disease and 8 patients died (non-PGCT related) during the follow-up. The NGS test of the malignant patient showed a significant increase in WRN, KMT2A, RPA1, NSD1, DDR2, ZNRF3, NOTCH4, CSF1R, FAT3, GRIN2A and RAD50 gene expression, while the benign patient showed no difference in gene data. CONCLUSIONS: PGCT is a rare pulmonary tumor with no specific features. Lung biopsy through surgery or bronchoscopy is the key for the diagnosis of PGCT. Gene sequencing of the malignant case revealed abnormal expression of genes with unclear significance via mechanisms that need to be further explored.