Feasibility of pathological evaluation of morcellated kidneys after radical nephrectomy.

PURPOSE: The indications for laparoscopic nephrectomy have grown to include renal malignancy. Although morcellation of these specimens has been described, to our knowledge we present the first systematic review of the feasibility and validity of pathological evaluation of these tumors with regard to grade and stage. MATERIALS AND METHODS: Nine formalin fixed and 5 fresh intact radical nephrectomy specimens were evaluated by 2 pathologists before and after high speed electrical tissue morcellation. The ability to distinguish tissue histology, and tumor size, stage and grade were compared. Impermeability of the laparoscopy sack after morcellation was also evaluated using indigo carmine stained normal saline placed in the used sack. RESULTS: The 9 preserved specimens included 7 renal cell carcinomas and 2 oncocytomas, while 4 of the 5 fresh specimens were renal cell carcinoma and 1 was oncocytoma. Overall tumor size was 2 to 7 cm. (mean 4.9). The 4 fresh renal cell carcinomas were of the clear cell type. Comparison of pathological evaluation after morcellation by another pathologist revealed identical histology, grade and stage for each tumor. Four cases of perinephric fat invasion (3 fixed and 1 fresh specimens) were identified after morcellation. Only tumor size was not assessed after morcellation. Laparoscopy sack integrity was confirmed in 13 of 14 cases. In 1 case involving a formalin fixed specimen a gross defect in the laparoscopy sack was demonstrated after morcellation. CONCLUSIONS: Morcellation of radical nephrectomy specimens in vitro did not alter the determination of histology, grade or local invasiveness of tumor. For all fresh tissue and remarkably for all but 1 formalin fixed tissue specimen the laparoscopy sack remained intact. Preliminary data from this in vitro model imply that limited in vivo morcellation of radical nephrectomy specimens may be performed without sacrificing staging information.