Inflammatory myofibroblastic tumour of the bladder may express anaplastic lymphoma kinase by translocation‐dependent and translocation‐independent mechanisms: a report of two cases

reported varies between studies; 97%, 89%, 67%, 46%, 29% to 15%. The grade and stage within these studies have not always been quoted and thresholds for positivity have differed, making comparisons difficult. In this study we observed 83% positivity in tissue sections compared with 93% positivity in bladder washings. Jiang and Buchumensky showed no correlation between CK expression and grade or stage. A recent publication has suggested the value of CK20 immunocytology. Reports in the literature suggest that CK13 is positive in well-differentiated lesions. No such association was apparent in our cases. The observation that bladder washings corresponding to tissue sections with CK13 basal staining are positive suggests that the cells shed into bladder washings are obtained from layers deeper within the epithelial layer. In summary, this study has indicated that bladder washings from TCCB patients provide cell populations that are predominantly malignant. As bladder washings from tumours with non-staining in the superficial layer had high ID scores, it can be inferred that the bladder washings contained not only superficial cells, but also cells from deeper layers.