Pulmonary Tumor With Notochordal Differentiation: A Case Report and Morphologic, Immunohistochemical and Molecular Study of Benign Notochordal Cell Tumor Originating in the Lung
Abstract Background: Extraosseous benign notochordal cell tumor is extremely rare, and there are only five reported cases worldwide. The presented case of pulmonary primary benign notochordal cell tumor is the sixth case, but the first to report the deletion mutation of EGFR gene exon 19. Case presentation: The patient was a 50-year-old asymptomatic woman, who had been followed up for 3 years for a nodule in the right lung. Six months after the wedge resection, the patient is alive without evidence recurrence or metastasis. The tumor was 7 millimeters in diameter and was well demarcated. The tumor was consisted of a sheet of large round vacuolated cells with small and bland nuclei. No connective tissue containing blood vessels or inflammatory cell infiltration was detected in the stroma. The tumor were positive for CK AE1/AE3, Vimentin, S100 and Brachyury. Deletion mutation of EGFR gene exon 19 was first detected and reported. Conclusions: We firstly reported the EGFR mutation of pulmonary primary benign notochordal cell tumor. Due to the rarity of this tumor, more reports are need to explore pathological characteristics, especially the molecular characteristics, in order to better understand the nature of tumors