Kidney morcellation in laparoscopic nephrectomy for tumor: Recommendations for specimen sampling and pathologic tumor staging

Joseph T. Rabban, Maxwell V. Meng, Ben Yeh, Theresa Koppie, Linda Ferrell, Marshall L. Stoller

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Laparoscopic nephrectomy is a novel approach for small renal tumors in selected patients; however, removal of the kidney through the small laparoscopic abdominal wall incision site requires the kidney to be morcellated into small fragments while still in situ, Morcellation presents two problems for the pathologist. First, guidelines for optimal sampling of morcellated fragments have not been described. Second, morcellation precludes complete pTNM tumor staging, in particular, tumor size, margins, and renal vein involvement. Based on our initial experience with 23 laparoscopic nephrectomies/nephroureterectomies (13 clinically suspected neoplasms, confirmed pathologically as renal cell carcinoma [RCC, n = 7], urothelial carcinoma of the renal pelvis [n = 3], angiomyolipoma [n = 1], and cystic nephroma [n = 1], and 10 clinically benign entities) and a conservative statistical model, we present a decision analysis model of various specimen sampling protocols that optimize cost, labor, or time to diagnosis (single vs sequential sampling). Using the tumor-to-kidney volume ratio (TKR), calculated from preoperative radiologic imaging and specimen gross weight, several specimen sampling algorithms were compared. For the average situation in which TKR is ≥0.15, the algorithm that most significantly optimizes cost and labor is one that initially samples 5% of the morcellated specimen. However, additional sampling may be required in one fourth of the cases. The optimal amount of sampled tissue may indeed be less than 5% because this assumes no suspicious tissue is grossly visible and in all our cases of RCC grossly visible tumor was identified. Additional nomograms for a spectrum of TKR, sampling success, and cost are presented to allow pathologists their own discretion in determining optimal sampling of the morcellated kidney. Tumor staging is severely limited by morcellation. Tumor size, renal capsule involvement, and renal vein involvement cannot be fully pathologically evaluated for RCC, whereas invasion cannot be definitively assessed for urothelial carcinoma of the renal pelvis. Knowledge of the radiologic features (lesion size, capsule, and vein involvement) is important in sampling and staging morcellated kidneys removed laparoscopically.

Original languageEnglish (US)
Pages (from-to)1158-1166
Number of pages9
JournalAmerican Journal of Surgical Pathology
Volume25
Issue number9
DOIs
StatePublished - Sep 3 2001

Keywords

  • Laparoscopic nephrectomy
  • Morcellation
  • PTNM
  • Renal neoplasm
  • Specimen sampling
  • Tumor staging

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine

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