PTPRC and pituitary gland adenoma: CD45 is a protein tyrosine phosphatase, also known as leukocyte common antigen (LCA), that is essential for the initiation of T-cell receptor signalling and is commonly used to diagnose lymphoid diseases [1].Although abnormal LCA expression has also been reported in nonhematopoietic malignancies, such as poorly differentiated colorectal adenocarcinoma, aggressive pituitary adenoma, spermatogonium, rhabdomyosarcoma, and metastatic undifferentiated carcinoma [2, 3], only three cases of lung neuroendocrine tumors with positive LCA expression have been reported in the literature [2, 4].