Case 67

Here are three cases of bladder TURBT samples, please share your interpretations.

Case 1:

1. What's your diagnosis?

A. Carcinoma in situ

B. Dysplasia

C: Low grade papillary carcinoma, non-invasive

D: High grade papillary carcinoma, non-invasive

E: Invasive papillary carcinoma

Case 2:

2. What's your diagnosis?

A. Carcinoma in situ

B. Dysplasia

C: Low grade papillary carcinoma, non-invasive

D: High grade papillary carcinoma, non-invasive

E: Invasive papillary carcinoma

Case 3:

3. What's your diagnosis?

A. Carcinoma in situ

B. Dysplasia

C: Low grade papillary carcinoma, non-invasive

D: High grade papillary carcinoma, non-invasive

E: Invasive papillary carcinoma

Answers for all three cases

Case 1: High grade papillary carcinoma, non-invasive; Case 2: High grade papillary carcinoma, non-invasive; Case 3: Invasive papillary carcinoma.

Feature

High-Grade Non-Invasive Papillary Urothelial Carcinoma (HGPUC)

Low-Grade Non-Invasive Papillary Urothelial Carcinoma (LGPUC)

Architectural Complexity

More complex papillae with frequent fusion and branching. May show an inverted growth pattern.

Papillae are thinner and more orderly with fibrovascular cores. Some branching or fusion may be present but less pronounced.

Cytological Atypia

Marked disorderly orientation of tumour cells with loss of polarity. Irregular, pleomorphic nuclei visible at low magnification. Nuclear hyperchromasia, prominent irregular nucleoli, and irregular nuclear contours are evident.

Mild nuclear atypia with mild loss of polarity. Scattered cells show nuclear hyperchromasia. Overall, nuclei display only mild variation.

Mitotic Activity

Frequent mitotic figures, including atypical forms.

Occasional mitotic figures, generally located away from the basal layer. Lower mitotic activity than HGPUC.

Nuclear Features

Significant nuclear size variation. Nuclear anaplasia may be present.

More uniform nuclear size. No marked variation in nuclear morphology.

Growth Pattern

Can exhibit an inverted growth pattern, which may pose diagnostic challenges when differentiating from invasive carcinoma. Preservation of stromal–epithelial interface helps confirm non-invasiveness.

Inverted nests are usually thickened but maintain characteristics similar to LGPUC. The structures are more uniform compared to inverted papillomas.

Risk of Progression

Higher risk of progression to invasive carcinoma.

Lower risk of progression compared to HGPUC.

References: https://tumourclassification.iarc.who.int/chaptercontent/36/72

Case credit: UCSD Pathology

Author: Wangpan Jackson Shi, MD