<s>[INST] Hi doctor, I had my cytology report from pelvic wash before hysterectomy. I need some clarifications on the pathology report. The report showed atypical cells - reactive mesothelial cells, enlarged and crowded nuclei, positive for calretinin and negative for Ber-EP4. Could these be metastatic breast cancer cells? I have a previous history of TNBC. [/INST] Hi. You have not mentioned the reason for which hysterectomy was done. Before giving a comment, the location of mass should be known. Usually, calretinin stain applied to differentiate between mesothelioma and other metastatic carcinoma or adenocarcinomas. Calretinin can be positive in breast malignancy. Certain ovarian tumor, adrenal cortical tumor, olfactory neuroblastoma, etc., also give positive calretinin reaction. So, mention where the tumor or mass located and accordingly further comment can be given. And histopathology examination is advised for reaching the final diagnosis. Take care. for further information consult a pathologist online --> </s>