MET exon 14 skipping mutation, amplification and overexpression in pulmonary sarcomatoid carcinoma: A multi-center study.

BACKGROUND: High frequency of MNNG HOS transforming (MET) exon 14 skipping mutation (MET exon 14Δ) has been reported in pulmonary sarcomatoid carcinomas (PSCs). However, the frequencies differ greatly. Our study aims to investigate the frequency of MET alterations and the correlations among MET exon 14Δ, amplification, and protein overexpression in a large cohort of PSCs. MET exon 14Δ, amplification, and protein overexpression were detected in 124 surgically resected PSCs by using Sanger sequencing, fluorescent in situ hybridization (FISH), and immunohistochemistry (IHC) respectively. MET exon 14Δ was identified in 9 (7.3%) of 124 cases, including 6 pleomorphic carcinomas, 2 spindle cell carcinomas and 1 carcinosarcoma. MET amplification and protein overexpression were detected in 6 PSCs (4.8%) and 25 PSCs (20.2%), respectively. MET amplification was significantly associated with overexpression (P < 0.001). However, MET exon 14Δ has no correlation with MET amplification (P = 0.370) and overexpression (P = 0.080). Multivariable analysis demonstrated that pathologic stage (hazard ratio [HR], 2.78; 95% confidence interval [CI], 1.28-6.01; P = 0.010) and MET amplification (HR, 4.71; 95% CI, 1.31-16.98; P = 0.018) were independent prognostic factors for poor median overall survival (mOS). MET alterations including MET exon 14Δ and amplification should be recommended as routine clinical testing in PSCs patients who may benefit from MET inhibitors. MET IHC appears to be an efficient screen tool for MET amplification in PSCs.

Invasive urothelial carcinoma with chordoid features of the ureter: a rare entity and review of literature.

Invasive urothelial carcinoma (UC) is characterized by some histologic variants that can sometimes lead to diagnostic difficulty. In addition to those described by the World Health Organization. Recently invasive urothelial carcinoma with chordoid features (UCC) has been described as a distinct entity and there are relatively few reported cases in the English-language literature. To date 13 cases of UCC have been reported in 2 case series, respectively in 2009 and 2015. We report the 14(th) case in an 80-year-old female, and to the best of our knowledge this is the second case report of UCC in the ureter. She was admitted to our hospital with macroscopic haematuria and unspecific left lower abdominal pain. Computed tomography scan revealed a soft tissue nodule in the middle of the left ureter. The left nephroureterectomy was performed. Morphologically, 85% areas had acellular myxoid stroma was associated with the neoplastic cells. The neoplastic cells had scant eosinophilic cytoplasm and were arranged into cords closely mimicking chordoma or extraskeletal myxoid chondrosarcoma. 15% areas was typical invasive urothelial carcinoma, and focal areas had transition phenomenon between them. Immunohistochemically, the tumor cells were positive for CK, 34ßE12 and p63, but were negative for S100, AFP, CD34, Syn and CgA. The final histopathological diagnosis was UCC of the ureter.