Sirohi D, et al. - Clinical, laboratory, and surgical pathology records were reviewed, and data were recorded for all cases in order to report 29 cases of amyloidosis in the bladder, 14 of which were discovered in association with urothelial carcinoma. The most prevalent entity was the presentation as a mass lesion (n = 18). Immunohistochemical subtyping performed in 17 cases explicated transthyretin-type (n = 10), AL (n = 3), AA (n = 1), amyloid P (n = 1), and undetermined (n = 2) types of amyloid. Eighteen cases were classified as localized primary amyloidosis and 11 as a secondary manifestation of systemic amyloidosis. In 14 cases, a correlated urothelial carcinoma was noted. In four of seven individuals with systemic amyloidosis and ten of 18 patients with localized amyloidosis, associated urothelial carcinoma was seen along with the variation not being statistically important. Results discovered urothelial carcinoma transpiring in 48% of the cases in relation to amyloidosis, a finding not formerly reported. The association of amyloid in the bladder and urothelial carcinoma, however likely not causal, seems to be an uncommon finding not often observed with other solid tumors.