Immunohistochemistry demonstrated tumor positivity for vimentin, epithelial membrane antigen (EMA), progesterone receptor (PgR), and thyroid transcription factor-1 (TTF-1) and negativity for cytokeratin and B-cell lymphoma-2 (Bcl-2), with a Ki-67 proliferation index of <1%. This evidence concerns the gene MKI67 and neoplasm.