Renal Mass in an Elderly Woman

Junqi Qian, M.D.

Specimen Type:

Kidney

History:

An 82-year-old female presented with a renal mass and underwent nephrectomy.

Pathologic Features:

Gross Description: The kidney measures 11 x 8.5 x 6 cm and weighs 338 grams. Noted protruding from the mid to lower kidney is a mass measuring about 8 cm in greatest dimension. Sectioning reveals a well-circumscribed orange-yellow-tan tumor measuring 8 x 7 x 7 cm with areas of hemorrhage. Representative sections are submitted for diagnosis.

Microscopic Features: The tumor consists of sheets and nests of cells bounded by delicate vascular septa. The majority of cells contain abundant clear cytoplasm and prominent nuclei and nucleoli (Fig. 1-5). Giant cells are also present (Fig. 6). The cancer cells are positive for vimentin (Fig. 7), focally positive for CD10 (Fig. 8), and RCC (Fig. 9), but negative for desmin, SMA, CK7, CD117 and colloidal iron stain.

Differential Diagnosis:

  • Clear Cell Renal Cell Carcinoma
  • Chromophobe Renal Cell Carcinoma
  • Oncocytoma
  • Sarcomatoid carcinoma

Diagnosis:

Grade 4 (of 4) Clear Cell Renal Cell Carcinoma.

Clear cell carcinoma accounts for 60%-70% of all cases of renal cell carcinoma. It is believed to arise in epithelial cells lining the proximal tubule. Grossly, clear cell carcinoma ranges in size from a few millimeters to very large, with an average size is about 7 cm. It is usually unilateral and unicentric; bilaterality and/or multicentricity are features of hereditary clear cell carcinoma. It commonly forms a bosselated mass that protrudes from the cortical surface. The cut surface is typically variegated with areas of grey-white fibrosis and recent or old hemorrhage.

Microscopically, clear cell carcinoma displays a variety of architectural patterns; tumor cells are arranged most often in sheets, compact nests, alveolar, acinar and microcystic or even macrocystic structures, separated by an abundance of thin-walled blood vessels. Tubular structures are variable in size. The classic cell of clear cell carcinoma has distinct cell membranes and optically clear cytoplasm due to loss of cytoplasmic lipids and glycogen during histologic processing. Some cases of clear cell carcinoma display varying numbers of cells with granular eosinophilic cytoplasm; such cells are more often seen in high grade cancer or near areas of hemorrhage or necrosis. The nuclei of clear cell carcinoma show considerable variation in nuclear size, nuclear shape, and nucleolar prominence.

Immunohistochemically, clear cell carcinoma typically shows positive immunostaining for vimentin, epithelial membrane antigen (EMA), renal cell carcinoma marker (RCC Ma), and CD10. It also tends to show positive immunostaining for low molecular weight cytokeratins (LMWCK) 8, 18, and 9; and keratins AE1 and Cam 5.2, although the frequency of staining with these markers varies considerably.

The prognosis for patients with clear cell carcinoma is discussed in the section on prognosis in renal cell carcinoma.

References:

  1. Lopez-Beltran A, Carrasco JC, Cheng L, Scarpelli M, Kirkali Z, Montironi R. 2009 update on the classification of renal epithelial tumors in adults. Int J Urol. 2009 May;16(5):432-43. Epub 2009 Apr 20. Review.
  2. Cheng L, Zhang S, MacLennan GT, Lopez-Beltran A, Montironi R. Molecular and cytogenetic insights into the pathogenesis, classification, differential diagnosis, and prognosis of renal epithelial neoplasms. Hum Pathol. 2009 Jan;40(1):10-29. Review.