Clinical Uroradiologic Conference Series Editors-Floyd
Number 11
Katske, M.D.,
and Zoran Barbaric,
M.D.
Unusual Presentation
Prashant Kundargi, M.D. Nagesh S. Nagapurkar, M.D. Sudhaunshu V. Chitale, M.D. Brijesh K. Agarwal, M.D.
of Renal Oncocytoma
Girish M. Warawdekar, Anita B. Shah, M.D. V. Srinivas, M.D. A. G. Phadke, M.D.
Case History History: A sixty-year-old man presented with symptoms of prostatism. There was no history of hematuria or any kind of abdominal pain. Physical examination was unremarkable. Rectal examination revealed a benign-feeling small prostate gland. Hematologic and bioLaboratory findings: chemical investigations revealed a normal bloodcount. Renal parameters were within normal limits. Radiographic findings: Ultrasound scanning prior to planned prostatic surgery showed a normal right kidney and a solid mass in the lower and mid zones of the left kidney, The pelvicaliceal system and ureters were nonobstructed. Intravenous urogram revealed a space-occupying lesion in the lower pole of the left kidney distorting the lower and middle calices (Fig. 1). Computed tomography showed the tumor to be solid and enhancing on post-contrast films (Fig. 2). Digital subtraction angiography showed a hypovascular tumor displacing the vessels. There were no areas of neovascularity or puddling (Fig. 3). Radiologic Provisional pernephroma.
diagnosis
M.D.
The specimen was opened Pathologic findings: and the kidney dissected. It measured 13 cm in length, 8 cm in width, and 7 cm in maximum anteroposterior diameter. The capsule could be stripped off easily, revealing a central subcapsular swelling. On cut section a globular smooth encapsulated tumor with a mahogany brown color and firm consistency was seen. Whitish scar-like areas were seen, but no necrosis. The central pelvicaliceal system was compressed but not infiltrated. The hilar vessels and capsule were not involved. The attached ureter measuring 7 cm was normal.
Diagnosis of hypovascular
left hy-
Treatment The patient was explored using an eleventh rib bed incision extending medially almost to the midline. The peritoneum was opened and vessels were secured. The kidney was removed along with perirenal fat and left adrenal gland without violating the Gerota fascia.
*From the Department of Urology, Division of Urologic Oncology, Bombay Hospital, Bombay, India 400 020.
354
FIGURE 1. UrogTam showing space-occupying sion in lower pole.
UROLOGY
/
OCTOBER
1992
/
le-
VOLUME 40, NUMBER 4
FIGURE 4. Microscopic features of tumor. (Hematoxylin and eosin, original magnification x 250.)
Final Diagnosis FIGURE
2.
CT showing solid tumor in lower pole of
left kidney.
The diagnosis of oncocytoma was confirmed by electron microscopy which showed abundant mitochondria and a dearth of most other organelles. Discussion
FIGURE 3. povascular.
Angiography
showing tumor to be hy-
Light microscopy revealed an epithelial neoplasm having a thin indistinct capsule (Fig. 4). Compact rounded balls of acidophilic granular oncocytic cells separated by thin-walled engorged vascular channels or sinusoids were seen. The nuclei were small, round, and vesicular and fairly regular in size. No mitotic activity was present although pleomorphic nuclei were seen. Resection margins were clear of tumor, perihilar fat, and a few lymph nodes were free of tumor.
UROLOGY
/ OCTOBER1992
/ VOLUME40,NUMBER4
Oncocytes are altered epithelial cells with finely granular eosinophilic cytoplasm and a cytoplasmic volume exceeding that of their cells of origin. Hamperl’ coined the term oncocytoma by hybridizing the Greek words “onkousthai” (to swell) and “cyte” (a cell) to convey their increased volume. It is now accepted that the term oncocytoma be restricted to neoplasms composed exclusively of oncocytes. Lesions fulfilling this criterion have been found in several sites including salivary glands, thyroid, parathyroids, and, only rarely, in the kidney2 Regardless of the organ of origin, ultrastructural study of oncocytes characteristically shows abundant mitochondria filling the cytoplasm of the cells. There is absence of fat vacuoles and microvilli, and desmosomes are attenuated.3 Oncocytoma has to be distinguished histologically from granular cell renal carcinoma. It is differentiated from this by the absence of papillary structures and by absence of necrosis and mitoses. On electron microscopy presence of abundant mitochondria and absence of fat vacuoles further distinguish these cells from clear and granular renal cell carcinoma. The angiographic features of oncocytomas have been described by many workers4m8and include (1) uniform blush during nephrogram phase; (2) wellmarginated lesion with smooth contours and with vessels stretched around tumor; (3) hypervascular neoplasm without evidence of puddling; and (4) spoke wheel appearance of tumor vascularity, with vessels converging toward the center.
355
Although the angiographic features are supposed to be diagnostic, this was not so in our case; on the contrary the tumor was hypovascular suggesting a hypovascular renal cell carcinoma. In view of the benign nature of the tumor a more conservative approach may be adopted if an oncocytoma is suspected on radiographic evidence, and in rare circumstances frozen section followed by partial nephrectomy may be done.’ In the majority of cases, however, radical nephrectomy still remains the standard method of therapy since it is difficult to diagnose this rare tumor preoperatively.
356
References 1. Hamper1 H: Benign and malignant oncocytomas, Cancer 15: 1019 (1962). 2. Jaffe RH: Adenolymphoma of the parotid gland, Am J Cancer 16: 1415 (1932). 3. Merino MJ, and Livolsi VA: Oncocytomas of the kidney, Cancer 50: 1852 (1982). 4. SOSTA, Gray &Jr, and Baltaxe HA: The angiographic apnearance of benign renal oxvnhil adenoma. AIR 127: 717 (1976). A 5. Weiner SNyand Ber&tkin RG: Renal &cocytoma, ‘angiographic features of two cases, Radiology 125: 633 (1977). 6. Ambos MA, Bosniak MA, and Valensi QO: Angiographic patterns in renal oncocytomas, Radiology 129: 615 (1978). 7. Srinivas V, Herr HW, and Hajdu EO: Partial nephrectomy for a renal oncocytoma associated with tuberous sclerosis, J Urol 133: 263 (1985).
UROLOGY
/
OCTOBER 1992
/
VOLUME 40. NUMBER 4
Number 11
Katske, M.D.,
and Zoran Barbaric,
M.D.
Unusual Presentation
Prashant Kundargi, M.D. Nagesh S. Nagapurkar, M.D. Sudhaunshu V. Chitale, M.D. Brijesh K. Agarwal, M.D.
of Renal Oncocytoma
Girish M. Warawdekar, Anita B. Shah, M.D. V. Srinivas, M.D. A. G. Phadke, M.D.
Case History History: A sixty-year-old man presented with symptoms of prostatism. There was no history of hematuria or any kind of abdominal pain. Physical examination was unremarkable. Rectal examination revealed a benign-feeling small prostate gland. Hematologic and bioLaboratory findings: chemical investigations revealed a normal bloodcount. Renal parameters were within normal limits. Radiographic findings: Ultrasound scanning prior to planned prostatic surgery showed a normal right kidney and a solid mass in the lower and mid zones of the left kidney, The pelvicaliceal system and ureters were nonobstructed. Intravenous urogram revealed a space-occupying lesion in the lower pole of the left kidney distorting the lower and middle calices (Fig. 1). Computed tomography showed the tumor to be solid and enhancing on post-contrast films (Fig. 2). Digital subtraction angiography showed a hypovascular tumor displacing the vessels. There were no areas of neovascularity or puddling (Fig. 3). Radiologic Provisional pernephroma.
diagnosis
M.D.
The specimen was opened Pathologic findings: and the kidney dissected. It measured 13 cm in length, 8 cm in width, and 7 cm in maximum anteroposterior diameter. The capsule could be stripped off easily, revealing a central subcapsular swelling. On cut section a globular smooth encapsulated tumor with a mahogany brown color and firm consistency was seen. Whitish scar-like areas were seen, but no necrosis. The central pelvicaliceal system was compressed but not infiltrated. The hilar vessels and capsule were not involved. The attached ureter measuring 7 cm was normal.
Diagnosis of hypovascular
left hy-
Treatment The patient was explored using an eleventh rib bed incision extending medially almost to the midline. The peritoneum was opened and vessels were secured. The kidney was removed along with perirenal fat and left adrenal gland without violating the Gerota fascia.
*From the Department of Urology, Division of Urologic Oncology, Bombay Hospital, Bombay, India 400 020.
354
FIGURE 1. UrogTam showing space-occupying sion in lower pole.
UROLOGY
/
OCTOBER
1992
/
le-
VOLUME 40, NUMBER 4
FIGURE 4. Microscopic features of tumor. (Hematoxylin and eosin, original magnification x 250.)
Final Diagnosis FIGURE
2.
CT showing solid tumor in lower pole of
left kidney.
The diagnosis of oncocytoma was confirmed by electron microscopy which showed abundant mitochondria and a dearth of most other organelles. Discussion
FIGURE 3. povascular.
Angiography
showing tumor to be hy-
Light microscopy revealed an epithelial neoplasm having a thin indistinct capsule (Fig. 4). Compact rounded balls of acidophilic granular oncocytic cells separated by thin-walled engorged vascular channels or sinusoids were seen. The nuclei were small, round, and vesicular and fairly regular in size. No mitotic activity was present although pleomorphic nuclei were seen. Resection margins were clear of tumor, perihilar fat, and a few lymph nodes were free of tumor.
UROLOGY
/ OCTOBER1992
/ VOLUME40,NUMBER4
Oncocytes are altered epithelial cells with finely granular eosinophilic cytoplasm and a cytoplasmic volume exceeding that of their cells of origin. Hamperl’ coined the term oncocytoma by hybridizing the Greek words “onkousthai” (to swell) and “cyte” (a cell) to convey their increased volume. It is now accepted that the term oncocytoma be restricted to neoplasms composed exclusively of oncocytes. Lesions fulfilling this criterion have been found in several sites including salivary glands, thyroid, parathyroids, and, only rarely, in the kidney2 Regardless of the organ of origin, ultrastructural study of oncocytes characteristically shows abundant mitochondria filling the cytoplasm of the cells. There is absence of fat vacuoles and microvilli, and desmosomes are attenuated.3 Oncocytoma has to be distinguished histologically from granular cell renal carcinoma. It is differentiated from this by the absence of papillary structures and by absence of necrosis and mitoses. On electron microscopy presence of abundant mitochondria and absence of fat vacuoles further distinguish these cells from clear and granular renal cell carcinoma. The angiographic features of oncocytomas have been described by many workers4m8and include (1) uniform blush during nephrogram phase; (2) wellmarginated lesion with smooth contours and with vessels stretched around tumor; (3) hypervascular neoplasm without evidence of puddling; and (4) spoke wheel appearance of tumor vascularity, with vessels converging toward the center.
355
Although the angiographic features are supposed to be diagnostic, this was not so in our case; on the contrary the tumor was hypovascular suggesting a hypovascular renal cell carcinoma. In view of the benign nature of the tumor a more conservative approach may be adopted if an oncocytoma is suspected on radiographic evidence, and in rare circumstances frozen section followed by partial nephrectomy may be done.’ In the majority of cases, however, radical nephrectomy still remains the standard method of therapy since it is difficult to diagnose this rare tumor preoperatively.
356
References 1. Hamper1 H: Benign and malignant oncocytomas, Cancer 15: 1019 (1962). 2. Jaffe RH: Adenolymphoma of the parotid gland, Am J Cancer 16: 1415 (1932). 3. Merino MJ, and Livolsi VA: Oncocytomas of the kidney, Cancer 50: 1852 (1982). 4. SOSTA, Gray &Jr, and Baltaxe HA: The angiographic apnearance of benign renal oxvnhil adenoma. AIR 127: 717 (1976). A 5. Weiner SNyand Ber&tkin RG: Renal &cocytoma, ‘angiographic features of two cases, Radiology 125: 633 (1977). 6. Ambos MA, Bosniak MA, and Valensi QO: Angiographic patterns in renal oncocytomas, Radiology 129: 615 (1978). 7. Srinivas V, Herr HW, and Hajdu EO: Partial nephrectomy for a renal oncocytoma associated with tuberous sclerosis, J Urol 133: 263 (1985).
UROLOGY
/
OCTOBER 1992
/
VOLUME 40. NUMBER 4
