Incidentally detected squamous cell carcinoma of renal pelvis in patients with staghorn calculi: case series with review of the literature

Abstract

Squamous cell carcinoma of the renal pelvis is a rare neoplasm, often unsuspected clinically due to its rarity and ambiguous clinical and radiological features, and hence patients present at advanced stages resulting in poor prognosis. We report here four cases of incidentally diagnosed primary renal squamous cell carcinoma, treated at our hospital over a short span of one year, and review the relevant literature. Mean age of the patients (3 males, 1 female) was 60 years. All suffered from staghorn stones. Interestingly, renal carcinoma was unsuspected clinically in all patients. In one case, a computerised tomography scan showed a suspicious nodule. All underwent nephrectomy for nonfunctioning kidney. In just two cases, tumor was identified on gross examination, while the other two only showed thickened pelvis. Our series emphasises the need for pelvicalyceal biopsy during treatment for long-standing nephrolithiasis, and thorough sampling of the renal pelvis in nephrectomy specimen of such patients.

Figure 1

Radiological images. (a) Plain X-ray (KUB) of Case 3 showing multiple radio-opaque shadows in the left kidney; (b) IVP skiagram of the same case at 15 min showing normal excretion of dye in the right kidney while there is complete absence of excretion in the left kidney. Dye excretion was not seen in the left kidney even up to 24 hours. Multiple renal stones can be seen in the left kidney similar to (a); (c) CT scan image of Case 4 showing small and irregular hydronephrotic right kidney with a nodule in the region of pelvis; (d) CECT image of Case 4 showing focal contrast enhancement in the nodule in pelvis.

Figure 2

Gross photographs of operated kidney specimen showing (a) marked hydronephrosis, dilated pelvicalyceal system with markedly thinned out renal parenchyma seen in Case 2. An area of thickening is seen at the upper pole (white arrow); (b) replacement of the whole kidney by a solid grey-white tumor in Case 3. The tumor is limited to the kidney. In situ renal stones are identified (black arrow) and there are features of hydronephrosis.

Figure 3

Microphotographs showing (a) well-differentiated SCC with keratin pearl formation seen in Case 1 and (b) poorly differentiated squamous cell carcinoma seen in Case 3. The tumor is comprised predominantly of undifferentiated malignant tumor cells with islands of clearly squamous cells interspersed without keratinisation as seen in this picture; (c) moderately differentiated SCC in Case 4 showing solid sheets of tumor cells arising from the pelvis and infiltrating renal parenchyma. The urothelium lining the pelvis shows squamous metaplasia and dysplasia; (d) the same case showing tumor cells forming true papillae with fibrovascular cores seen in other areas; (e) all cases showed features of chronic pyelonephritis in the surrounding kidney as can be seen here in Case 3; (f) perineural invasion (arrow) of tumor cells seen in Case 2; (g) section from Case 1 with infiltration of the perirenal fat by the tumor cells.