1. Localized Urinary Bladder Amyloidosis as Urothelial Cancer Mimicker: A Case Series Examining Cystoscopic, Histologic, and Cytologic Findings
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Regmi, Aayushma, Mehta, Maitri, Farooq, Ahmer V., Turk, Thomas M., Wojcik, Eva M., and Picken, Maria M.
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Medical research ,Medicine, Experimental ,Cytology -- Usage ,Cystoscopy -- Usage ,Bladder diseases -- Physiological aspects -- Case studies ,Amyloidosis -- Physiological aspects -- Case studies ,Urinary tract cancer -- Physiological aspects -- Case studies ,Histology -- Usage - Abstract
* Context.--Localized amyloidosis of the bladder is rare and often mimics bladder malignancy. It is typically associated with the extracellular deposition of monoclonal light chains, either [kappa] or [lambda]. The cause is unknown, but it is thought to be due to chronic inflammation/cystitis. Objective.--To highlight the importance of localized urinary bladder amyloidosis as a rare mimicker of urothelial malignancy and elucidate its clinical, histopathologic, and cytopathologic manifestations. Design.--Cases of urinary bladder amyloidosis diagnosed during 2000-2023 were retrieved retrospectively from pathology archives. Electronic medical records, including cystoscopy findings and pathology slides including Congo red stain, were reviewed. Results.--Here we present 6 patients with localized urinary bladder amyloidosis. Four of the 6 patients were women, with ages ranging from 46 to 69 years, and a mean age of 58 years. Five of 6 patients presented with hematuria, while in 1 patient, bladder amyloidosis was discovered incidentally. Cystoscopy findings invariably were concerning for malignancy, with raised erythema in 5 patients and fungating mass protruding into the bladder lumen in 1 patient. Bladder biopsies and urine cytology were negative for malignancy in all cases. Congo red-positive amyloid deposits involved lamina propria with sparing of the detrusor muscle. In 5 cases, the deposits were typed as derived from the k light chain, whereas no information was available for 1 patient. Subsequent clinical workup ruled out systemic amyloidosis. Conclusions.--These cases of urinary bladder amyloidosis highlight the importance of considering rare amyloidosis in the differential diagnosis of hematuria and cystoscopy with a lesion mimicking malignancy. (Arch Pathol Lab Med. 2025;149:191-194; doi: 10.5858/arpa.2023-0559-OA), Amyloidosis is the deposition of insoluble amyloid protein fibrils in various tissues and organs. (1) Amyloidosis can be associated with an underlying plasma cell dyscrasia, sustained chronic inflammation, chronic hemodialysis, [...]
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- 2025
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