Squamous Cell Carcinoma in a Calyceal Diverticulum Detected by Percutaneous Nephroscopic Biopsy

Abstract

A 73-year-old woman was referred to our department with a complaint of asymptomatic gross hematuria. Dynamic computed tomography revealed a complicated (Bosniak type IIF) cyst in the upper pole of her right kidney, which was diagnosed as a calyceal diverticulum. The diagnosis was confirmed by ureteroscopy. The diverticulum was filled with a soft protein matrix that was difficult to completely remove from the inner surface of the calyceal diverticulum. Endoscopy combined with intrarenal surgery (ECIRS) was performed to completely remove the matrix. Percutaneous nephroscopy further revealed papillary lesions on the surface of the diverticulum, confirmed as squamous cell carcinoma on pathological assessment. A laparoscopic right radical nephroureterectomy was performed, with curative intent. Pathological assessment confirmed a high-grade squamous cell carcinoma with renal parenchymal invasion (pT3). Although carcinomas in a calyceal diverticulum are highly uncommon, when present, these tend to be high-grade neoplasms that deeply invade the parenchymal wall. As the effective management of these lesions is difficult, early-stage diagnosis is required for curative treatment. We report the case of squamous cell carcinoma in a calyceal diverticulum that was difficult to diagnose on preoperative computed tomography, urinal cytology examination, and ureteroscopy but was found during ECIRS.

Figure 1

(a) Plain computed tomography image, showing a stone in the right upper urinary tract, but with no indication of the soft protein matrix in the right renal pelvis and calyceal diverticulum, which is radiolucent. (b) Dynamic computed tomography image, showing a complicated cyst, classified as a Bosniak type IIF cyst, arising from the right side of the kidney.

Figure 2

Retrograde pyelogram image, showing a duplex collecting system in the right kidney and calyceal diverticulum connected to the upper renal calyx. Defect sign of retrograde pyelogram, caused by filling of the diverticulum by the soft protein matrix, is observable. A percutaneous nephrostomy tube in the diverticulum was placed prior to ECIRS to remove the contents completely.

Figure 3

Percutaneous nephroscopic examination, showing papillary lesions in the calyceal diverticulum.

Figure 4

Histopathological examination. (a) An area of verrucous squamous cell carcinoma, connected to a high-grade squamous cell carcinoma, identified on the inner surface of the calyceal diverticulum. (b) Under magnification, the high-grade squamous cell carcinoma was shown to invade the renal parenchyma.