COW-2019-27

CASE OF THE WEEK

2019-27 / AUGUST 19
(CONTRIBUTORS: PETER YOUSEF & FADI BRIMO)

74 year old male presenting with gross hematuria and a bladder mass on cystoscopy.

Quiz

1. What is the correct diagnosis?

a. Papilloma

b. Fibrosis of the lamina propria

c. Amyloidosis

d. Non-specific hemorrhage of the lamina propria

1. Amyloidosis

The pictures show hemorrhage in the lamina propria associated with the deposition of pink, amorphous material that stain positive with Congo red stain and show apple green birefringence under polarized light consistent with amyloidosis. The overlying urothelium is reactive and displays polypoid projections in the absence of a papillary tumor.

Amyloidosis involving the bladder can be either a manifestation of systemic amyloidosis or may be localized to the bladder.
Systemic amyloidosis has traditionally been classified to:
1- Primary (AL type) which is due to plasma cell disorders causing a buildup of antibody lambda light chains which aggregate and are inappropriately deposited in various organs. This is most often seen with multiple myeloma.
2- Secondary (AA type) which is a complication of many ongoing inflammatory or autoimmune conditions causing an elevation of acute phase reactants, leading to AA deposition in various organs with the kidney being most commonly involved.
3- Transthyretin (TTR) type which may be hereditary due to mutated TTR gene or may be found normally with aging. TTR most commonly deposits in the heart or the central nervous system.
In comparison, localized bladder amyloidosis has an unknown etiology and is usually of the AL type.

Clinical presentation is typically nonspecific such as in this patient and may mimic malignancy with gross hematuria and a mass on cystoscopy. Pink, amorphous material is seen in the lamina propria and muscularis propria and may involve the perivascular spaces as well. Surrounding histiocytic and foreign body giant cell reaction may be seen. Congo red stain is usually diagnostic. Alternatively, fluorescence with Thioflavin T stain can be demonstrated, and electron microscopy may be used to identify the condition. Due to its rarity, amyloidosis of the bladder may be overlooked and interpreted as non-specific fibrosis of the lamina propria which may display a similar morphology. In such cases, a negative Congo red stain and a positive trichrome stain are key diagnostic elements.

Once the diagnosis is made, patients should be assessed clinically to determine whether the disease is systemic or localized in nature. In addition, determining the type of amyloid protein deposited may help in the clinical work-up. In patients with persistent or severe local symptoms, resection or fulguration of the lesion may be required to control the symptoms, but a high rate of recurrence has been reported, thus follow up with cystoscopy is recommended.

Zhou F, Lee P, Zhou M, Melamed J, Deng FM. Primary localized amyloidosis of the urinary tract frequently mimics neoplasia: a clinicopathologic analysis of 11 cases.
Am J Clin Exp Urol. 2014 Apr 5;2(1):71-5. eCollection 2014.

Ho A, Davies MC, Guran R, Brewin J. Primary amyloidosis of the bladder.
Urol Case Rep (2018); 17:111-113.

Peter Yousef
Fadi Brimo
McGill University Health Center
fadi.brimo@mcgill.ca

Bladder

amyloidosis, bladder, mass