Consult with the pediatric pathologist if this is your first time to deal with this type of specimen.
Weigh and measure (three dimensions) the specimen.
Photograph the intact specimen. Examine the external surface, noting areas suspicious for tumor involvement. Then, ink the external surface.
Bivalve the specimen through an area which will best demonstrate the relationship of the tumor to renal structures (i.e. renal vessels, renal pelvis, renal sinus) but NOT through any areas suspicious for capsular penetration by tumor. The reason for this is that the capsule may retract following sectioning, preventing microscopic documentation of capsular penetration. Next, photograph the cut surface. Take tissue for cytogenetics and frozen tissue bank.
Fix in formalin overnight in the refrigerator (these tumors are too soft to section in the unfixed state). Refrigeration will slow autolysis. If the specimen is especially large, you may need to make one or two additional cuts in the same plane as the initial cut to ensure adequate formalin penetration.
Never strip the capsule – you will pull away nephroblastic rests.
Describe the tumor (measurements in three dimensions, location within the kidney, distances from renal capsule and renal sinus, circumscription, color, consistency). Determine if it is multicentric (multifocal). Describe the uninvolved kidney.
Draw a section map(i.e. picture of the major tumor surface indicating where sections have been taken, labeling each section with the corresponding cassette number). This is necessary for determining diffuse vs. focal anaplasia and will be included as a permanent part of the report.
Tumor: minimum of one section per centimeter of tumor. Include adjacent renal capsule (especially areas of suspected capsular penetration), renal sinus, and uninvolved kidney parenchyma in several sections. Most of the “random” tumor sections should be from the periphery of the tumor, rather than from the interior. If tumor is multicentric, sample each individual tumor using the same rules.
Uninvolved kidney: this area must be well-sampled to determine the presence of nephrogenic rests.
Renal sinus/hilus: two or more sections (approximately five sections total when including those with tumor).
* The renal sinus consists of the pelvocalyceal system, soft tissue, vessels, and nerves. It is a major route extrarenal tumor extension and, therefore, is critical to tumor staging.
Capsule: two or more sections (approximately five sections total when including those with tumor).
Ureter, renal artery, and renal vein: one cross-section of the resection margin, en face. Additional sections proximal to resection margins (in separate cassettes) if suspicious for tumor involvement.
Received without fixative/in formalin, labeled _____ and “_____”, is a __ g, __ x __ x __ cm nephrectomy specimen. It consists of a __ x __ x __ cm kidney surrounded by adipose tissue ranging from __ to __ cm in thickness. The external surface is inked black prior to sectioning and overnight fixation. There is a well-/poorly-circumscribed mass, __ x __ x __ cm, located in the _____ pole/mid portion. It has a _____ (color, consistency, friable, bulging, necrotic, hemorrhagic) cut surface. The mass is __ cm from/involves the renal sinus and __ cm from/immediately underlies/appears to transgress the renal capsule. The ureteral stump is __ cm in length and __ cm in diameter at the resection margin. There is __ cm of renal vein and __ cm of renal artery, each with a diameter of __ cm. A mass is/is not identified within the ureter/renal vessels along their length/at the resection margin. There are a few _____ (color) nodular areas, ranging from __ to __ cm in diameter, within the uninvolved adjacent renal parenchyma in the _____ (location), __ cm from the mass. The remainder of the uninvolved renal parenchyma is _____ (describe). The mucosa of the pelvocalyceal region is _____ (describe). Photographs are taken of the intact unfixed specimen, the sectioned unfixed specimen, and the sectioned fixed specimen. Tissue is submitted for cytogenetics, frozen tissue bank, and NTWS protocol. A section map is drawn to indicate location of submitted tissue blocks. Representatively submitted as follows:
#__ = renal vessels resection margin, en face
#__ = ureter resection margin, en face
#__ - #__ = mass and lateral portion of kidney with capsule, lateral
#__ & #__ mass and lower pole of kidney with capsule, inferior
#__ & #__ mass and medial portion of kidney with capsule , medial
#__ & #__ = mass and adjacent renal sinus
#__ & #__ = mass, central
#__ & #__ = uninvolved renal parenchyma and capsule, upper pole
#__ & #__ = uninvolved renal sinus
Reference for entire pediatric kidney section: Beckwith JB. Clinicopathological Correlations in Pediatric Renal Neoplasia. Society for Pediatric Pathology Workshop Syllabus, March 1996.