Small Renal Tumor Biopsies After Cryoablation Therapy
Small Renal Tumor Biopsies After Cryoablation Therapy
Fifty consecutive cases of intraoperative cryoablated SRT biopsy specimens obtained between July 2006 and August 2011 at Denver Health Medical Center were retrospectively reviewed. Patients with a renal mass 5 cm or smaller and a Bosniak renal cyst classification greater than Bosniak IIF or a suspected angiomyolipoma (AML) were considered for laparoscopic cryoablation. Two patients had von Hippel–Lindau syndrome, and all SRTs were discovered incidentally or after complaints of hematuria and/or abdominal pain.
Renal cryoablation was performed using a transperitoneal approach with real-time intraoperative laparoscopic ultrasound of the tumor. Three 17-gauge cryoprobes were used to create an optimal killing zone (surgical margin) for the ice ball. Cryoablation included two 6-minute freeze cycles and two active thaw cycles until renal tissue and cryoprobes were visible on ultrasound. During each cycle, a minimum killing zone temperature of −20°C with a core temperature of less than −100°C was reached. Two renal mass biopsies were performed using a Tru-Cut 18-gauge needle (Cardinal Health) under ultrasound guidance after the first or second cycle of freezing.
The biopsy specimens were formalin fixed, paraffin embedded, and routinely processed. Two initial H&E-stained sections were examined initially, and additional levels and/or immunohistochemical stains were used as needed at the time of rendering the original diagnosis. The empirically used diagnostic criteria were used as listed in the World Health Organization's "Tumors of the Urinary System and Male Genital Organs" for tumor subtyping. Nuclear grading was attempted, guided by the Fuhrman system Table 1. Due to freeze effect causing artifactual nuclear shrinking, crowding/overlapping (complicating accurate size assessment) with mild membrane irregularities, and obscured chromatin details (chromatin pattern and nucleoli) at ×10 objective, it was difficult to assign a definite numerical Fuhrman nuclear grade (FNG) of I or II; therefore, the term low nuclear grade (LNG) was used in these cases. For relatively enlarged nuclei, approximately 15 μm or greater (compared with intact red blood cells or lymphocytes), with the presence of nucleoli, FNG II or III was suggested.
Immunohistochemical staining was performed according to the standard protocol. The following antibodies were used to support or confirm tumor diagnosis: CD10 (56C clone, 1:40; Cell Marque, Rocklin, CA), CK7 (OV-TL 12/30, 1:100; Dako, Carpinteria, CA), EMA (E29, 1:2,000; Dako), vimentin (V9, 1:800; Dako), AMACR/p504S (Biocare, Concord, CA), smooth muscle actin (SMA) (1A4, 1:200; Dako), HMB-45 (HMB-45, 1:50; Dako), Melan-A (A103, 1:800; Dako), CD31 (JC70A, 1:100; Dako), CD3 (anti–human CD3, 1:500; Dako), CD5 (clone CD5/54/F6, 1:50; Dako), CD20 (clone L26, 1:500; Dako), and bcl-2 (clone 124, 1:400; Dako).
Materials and Methods
Fifty consecutive cases of intraoperative cryoablated SRT biopsy specimens obtained between July 2006 and August 2011 at Denver Health Medical Center were retrospectively reviewed. Patients with a renal mass 5 cm or smaller and a Bosniak renal cyst classification greater than Bosniak IIF or a suspected angiomyolipoma (AML) were considered for laparoscopic cryoablation. Two patients had von Hippel–Lindau syndrome, and all SRTs were discovered incidentally or after complaints of hematuria and/or abdominal pain.
Renal cryoablation was performed using a transperitoneal approach with real-time intraoperative laparoscopic ultrasound of the tumor. Three 17-gauge cryoprobes were used to create an optimal killing zone (surgical margin) for the ice ball. Cryoablation included two 6-minute freeze cycles and two active thaw cycles until renal tissue and cryoprobes were visible on ultrasound. During each cycle, a minimum killing zone temperature of −20°C with a core temperature of less than −100°C was reached. Two renal mass biopsies were performed using a Tru-Cut 18-gauge needle (Cardinal Health) under ultrasound guidance after the first or second cycle of freezing.
The biopsy specimens were formalin fixed, paraffin embedded, and routinely processed. Two initial H&E-stained sections were examined initially, and additional levels and/or immunohistochemical stains were used as needed at the time of rendering the original diagnosis. The empirically used diagnostic criteria were used as listed in the World Health Organization's "Tumors of the Urinary System and Male Genital Organs" for tumor subtyping. Nuclear grading was attempted, guided by the Fuhrman system Table 1. Due to freeze effect causing artifactual nuclear shrinking, crowding/overlapping (complicating accurate size assessment) with mild membrane irregularities, and obscured chromatin details (chromatin pattern and nucleoli) at ×10 objective, it was difficult to assign a definite numerical Fuhrman nuclear grade (FNG) of I or II; therefore, the term low nuclear grade (LNG) was used in these cases. For relatively enlarged nuclei, approximately 15 μm or greater (compared with intact red blood cells or lymphocytes), with the presence of nucleoli, FNG II or III was suggested.
Immunohistochemical staining was performed according to the standard protocol. The following antibodies were used to support or confirm tumor diagnosis: CD10 (56C clone, 1:40; Cell Marque, Rocklin, CA), CK7 (OV-TL 12/30, 1:100; Dako, Carpinteria, CA), EMA (E29, 1:2,000; Dako), vimentin (V9, 1:800; Dako), AMACR/p504S (Biocare, Concord, CA), smooth muscle actin (SMA) (1A4, 1:200; Dako), HMB-45 (HMB-45, 1:50; Dako), Melan-A (A103, 1:800; Dako), CD31 (JC70A, 1:100; Dako), CD3 (anti–human CD3, 1:500; Dako), CD5 (clone CD5/54/F6, 1:50; Dako), CD20 (clone L26, 1:500; Dako), and bcl-2 (clone 124, 1:400; Dako).