Primary low-grade B-cell lymphoma of mucosa-associated lymphoid tissue type arising in the urinary bladder: report of 4 cases with molecular genetic analysis.
BACKGROUND
Primary lymphoma of the urinary bladder is rare. Only 84 cases have been reported in the English literature to date, and none of these cases has had molecular confirmation of clonal immunoglobulin gene rearrangement.


OBJECTIVE
To review all cases with primary urinary bladder lymphoma in our records, to classify them using the REAL classification, to confirm their immunophenotype and genotype, and to determine their outcome.


METHODS
We identified 4 cases of primary urinary bladder lymphoma in our medical records from a 30-year period. Immunohistochemical detection of immunoglobulin light chains and molecular analysis of immunoglobulin heavy-chain genes using the polymerase chain reaction were performed on paraffin-embedded material.


RESULTS
All patients were older than 60 years. The male-female ratio was 1:3. All patients had a history of chronic cystitis. Histologic features of mucosa-associated lymphoid tissue lymphoma with centrocyte-like cells, plasmacytoid B cells, or both were observed in all cases. Monoclonality of B cells was demonstrated by immunohistochemistry, polymerase chain reaction, or both methods in every case. All patients presented with stage IAE disease, were treated with radiotherapy alone, and have been in continuous complete remission for 2 to 13 years.


CONCLUSIONS
Primary bladder lymphomas are usually of low-grade mucosa-associated lymphoid tissue type. They are more common in females and are associated with a history of chronic cystitis. Lymphoepithelial lesions are seen only in association with areas of cystitis glandularis. B-cell clonality is readily demonstrable by immunohistochemistry and/or polymerase chain reaction analysis. Local radiotherapy appears to confer long-term control.
Al-Maghrabi
J
J
Department of Laboratory Medicine and Pathobiology, Princes Margaret Hospital, University Health Network, University of Toronto, Ontario.
Kamel-Reid
S
S
Jewett
M
M
Gospodarowicz
M
M
Wells
W
W
Banerjee
D
D
D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D005260:Female; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D006801:Humans; D007150:Immunohistochemistry; D016393:Lymphoma, B-Cell / Q000737:chemistry / Q000145:classification / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology; D018442:Lymphoma, B-Cell, Marginal Zone / Q000737:chemistry / Q000145:classification / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011859:Radiography; D016896:Treatment Outcome; D001749:Urinary Bladder Neoplasms / Q000737:chemistry / Q000145:classification / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology*
D015703:Antigens, CD