An exophytic erythematous nodule is seen on the lateral wall of the bladder (just left of the center, slightly out of focus).
Low-grade papillary carcinoma is characterized by low-grade neoplastic urothelium lining papillary fronds. At scanning power, the urothelial lining appears benign, very much like a papillary urothelial neoplasm of low malignant potential (PUNLUMP). However, upon closer inspection, there will be obvious variation in the size and shape of the urothelial cells, as well as mild disorganization in the overall architecture.
At higher power, one can appreciate mild variations in nuclear size and shape. Furthermore, the cells are slightly disordered in their orientation. Scattered hyperchromatic nuclei are present.
Although low-grade papillary carcinoma is generally non-invasive, a minority of these tumors (~5%) do invade, eventually progressing into advanced disease and death. Therefore, some pathologists use the designation invasive or non-invasive low-grade papillary carcinoma'. In contrast, a significant proportion (15-40%) of high-grade papillary carcinomas are invasive, and it is probably wise to also add the qualifier invasive or non-invasive papillary carcinomas.1
You may be thinking, "Doesn't 'carcinoma' mean invasion and thus, the term 'invasive carcinoma' would be redundant?" The answer to your question is yes -- however, categorization of urothelial neoplasms has evolved differently. High-grade or low-grade papillary carcinomas does not implicate invasion. You must add the term invasive to designate invasion. Note also that invasion can rise from flat urothelial lesions or papillary urothelial lesions. These terms are not completely logical, but nonetheless, one must make peace with this.
M:F ratio is approximately 3:1 and the average age at presentation is 69.2 years (range of 28 to 90). The endoscopic appearance is usually that of a single papillary lesion located at the lateral wall or posterior wall of the bladder. In approximately 22% of cases, there are multiple lesions.1
Bladder tumors classically present with painless hematuria. Frequency, urgency and dysuria may occasionally be present.
Transurethral resection is the cornerstone of treatment. Multifocal or recurrent disease may sometimes be treated with intravesical immunotherapy such as administration of BCG (an attenuated strain of Mycobacterium tuberculosis called Bacilllus Calmette-Guerin), which elicits an immune reaction that destroys tumor cells.2
Progression to invasion and death occurs in less than 5% of cases. Recurrence is much more common (estimates range from 48% to 71% of cases) and may recur as a higher-grade tumor.1
1 Zhou M, Magi-Galluzzi, C. Genitourinary Pathology: Foundations in Diagnostic Pathology. Philadelphia, PA: Elvesier; 2006: 171-2.
2 Kumar V, Abbas AK, Fausto N. Robbins and Cotran Pathologic Basis of Disease. 7th Ed. Philadelphia, PA: Elsevier; 2005: 1028-33.