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PATHOLOGY
doi: 10.1590/S1677-55382010000400020
Low-grade
papillary urothelial carcinoma of the urinary bladder: a clinicopathologic
analysis of a post-world health organization/international society of
urological pathology classification cohort from a single academic center
Miyamoto H, Brimo F, Schultz L, Ye H, Miller JS, Fajardo DA, Lee TK, Epstein
JI, Netto GJ
Department of Pathology, Johns Hopkins University, Baltimore, Maryland,
USA
Arch Pathol Lab Med. 2010; 134: 1160-3
- Context:
Few large cohort studies have addressed outcome in patients with noninvasive
low-grade papillary urothelial carcinoma (LG-UrCa) following implementation
of the 2004 World Health Organization/International Society of Urological
Pathology (WHO/ISUP) consensus classification.
Objective: To evaluate our cohort of LG-UrCa cases classified according
to 2004 WHO/ISUP to reassess outcome and interobserver agreement.
Design: Files were searched for all patients diagnosed with LG-UrCa
between 1998 and 2008. All sections were reevaluated for accuracy of
classification.
Results: A total of 112 cases initially diagnosed as LG-UrCa were identified.
Of those, 8 of 55 cases (15%) initially diagnosed by nonurologic pathologists
were reclassified as high-grade papillary urothelial carcinoma and were
excluded. The mean length of follow-up was 40.1 months (range, 2-113
months). Tumor recurrence was encountered in 56 of 104 patients (53.8%),
including 37 (35.6%) with LG-UrCa or lower-grade tumors and 19 (18.3%)
with high-grade papillary urothelial carcinoma. Of the 19 patients demonstrating
grade progression, 7 (37%) also developed stage progression (invasive
carcinoma, n = 5; metastatic carcinoma, n = 2). Seven patients eventually
underwent radical cystectomy. None of the 104 patients died of bladder
cancer. The mean number of recurrence episodes was 3.11. The mean durations
of time to first recurrence and time to grade progression were 13.9
months and 25.1 months, respectively. The mean size of initial tumors
was 1.73 cm. There was no significant correlation between tumor size,
patient age, sex, or smoking history and the likelihood for recurrence
or grade progression. A significantly higher rate of recurrence was
seen in patients with multiple tumors at initial diagnosis (P = .04).
Conclusions: A tendency to underdiagnose high-grade papillary urothelial
carcinoma continues to exist. More than half (53.8%) of patients with
LG-UrCa developed recurrence, with an 18.3% incidence of grade progression
and a 6.7% incidence of stage progression. Patients with multiple initial
tumors had significantly higher risk of developing recurrence.
- Editorial
Comment
This is a large cohort study of outcome of patients with noninvasive
low-grade urothelial carcinoma using the World Health Organization/International
Society of Urological Pathology (WHO/SIPU) consensus classification.
From a total of 104 patients, 53.8% developed recurrence, with an 18.3%
incidence of grade progression and a 6.7% incidence of stage progression.
Patients with multiple initial tumors had significantly higher risk
of developing recurrence.
The World Health Organization/International Society of Urological Pathology
(WHO/SIPU) consensus classification was held in Boston in 1998 during
the United States and Canadian Academy of Pathology (USCAP) meeting.
The results were published in the American Journal of Surgical Pathology
(1). The most important recommendations of the meeting were:
1. It was recommended not to use the traditional term “dysplasia”.
For the term moderate dysplasia was recommended to use low-grade intra-urothelial
neoplasia and for severe dysplasia or flat carcinoma in situ the term
high-grade intra-urothelial neoplasia. Cases with slight dysplasia should
be reported by the pathologists.
2. The 1, 2 and 3 grading by the World Health Organization was replaced
by low-grade or refer to grade 1, and high-grade to refer to grades
2 or 3.
3. “Urothelial papilloma” without qualifiers refers to the
exophytic variant of papilloma, defined as a discrete papillary growth
with a central fibrovascular core lined by urothelium of normal thickness
and cytology. It is a rare benign condition typically occurring as a
small, isolated growth commonly, but not exclusively, in younger patients.
4. It was introduced the term “papillary urothelial neoplasm of
low malignant potential”. This is a papillary urothelial lesion
with an orderly arrangement of cells within papillae with minimal architectural
abnormalities and minimal nuclear atypia irrespective of cell thickness.
Patients with these tumors are at risk of developing new bladder tumors
of a similar histology. However, occasionally these subsequent lesions
manifest as urothelial carcinoma, such that follow-up of the patient
is warranted. In the standard classification this tumor corresponds
to the “papillary urothelial carcinoma, grade 1 (low-grade), pTa”.
This new category avoid labeling a patient as having cancer, which has
psychosocial and financial (e.g. insurance) implications, but neither
is a benign lesion (e.g., papilloma) diagnosed, so the patient might
be adequately followed (2).
References
- Epstein
JI, Amin MB, Reuter VR, Mostofi FK: The World Health Organization/International
Society of Urological Pathology consensus classification of urothelial
(transitional cell) neoplasms of the urinary bladder. Bladder Consensus
Conference Committee. Am J Surg Pathol. 1998; 22: 1435-48.
- Epstein
JI, Reuter VE, Amin MB: Biopsy Interpretation of the Bladder, 2nd ed.
Philadelphia, Lippincott Williams & Wilkins. 2010.
Dr.
Athanase Billis
Full-Professor of Pathology
State University of Campinas, Unicamp
Campinas, São Paulo, Brazil
E-mail: athanase@fcm.unicamp.br
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