Older Female with Renal Mass

Deloar Hossain, M.D.

Specimen Type:

Right Kidney

History:

79 year-old female with right renal mass.

Pathologic Features:

Gross Features: 2 cm white, friable solid mass in the right upper pole of the kidney involving the renal calyces and portions of the renal pelvis.

Microscopic Description: The tumor consists of nests atypical squamous cells (Fig 1, 2 and 3), many of which exhibit abundant keratinization (Fig 5, 6); foci of papillary architecture are also present. The majority of the tumor is not invasive and arises within the renal pelvis. However, focal extension into perirenal adipose tissue (Fig 7) and renal parenchyma (Fig 6) are noted.

Differential Diagnosis:

  • Urothelial carcinoma with squamous differentiation
  • Squamous cell carcinoma of the renal pelvis

Urothelial carcinoma with squamous differentiation: Squamous differentiation, as defined by the presence of keratinization or intracellular bridges, occurs in around 20% of urothelial carcinomas. Cases with foci of squamous differentiation may respond less favorably to therapy, and focal squamous differentiation in low-grade urothelial carcinoma results in a higher recurrence rate than pure low-grade urothelial carcinoma.

Squamous cell carcinoma of the renal pelvis: Pure squamous cell carcinoma of the renal pelvis comprises 10% of renal pelvic tumors. Risk factors include chronic infection, calculi, and horseshoe kidney. The most common presenting symptom is flank pain and hematuria. Most squamous cell carcinomas of the renal pelvis (and ureter) are high grade; extensive infiltration of the renal parenchyma is common. Survival to 5 years is uncommon. The diagnosis of squamous cell carcinoma should be rendered only in the absence of urothelial differentiation. In addition, metastatic squamous cell carcinoma of the bladder should be excluded, which usually easily accomplished with clinical correlation.

Diagnosis:

Invasive grade 3 (of 3) squamous cell carcinoma and squamous cell carcinoma in situ.

  • Flank pain and hematuria are presenting symptoms
  • Diagnosis only in absence of urothelial components
  • Frequently are high grade
  • Survival to 5 years uncommon

References:

  1. Utz DC, Mc DJ. Squamous cell carcinoma of the kidney. J Urol 1957; 78: 540-552.
  2. Li MK, Cheung WL. Squamous cell carcinoma of the renal pelvis. J Urol 1987; 138: 269-271.
  3. Strobel SL, Jasper WS, Gogate SA, et al. Arch Pathol Lab Med 1984; 108: 697-700.
  4. Busby JE, Brown GA, Tamboli P, et al. Upper urinary tract tumors with non-transitional histology: a single center experience. Urology 2006; 67: 519-523.