Distinguishing Clear Cell Renal Cell Carcinoma, Retroperitoneal Paraganglioma, and Adrenal Cortical Lesions on Limited Biopsy Material Utility of Immunohistochemical Markers
James E. Lapinski, MD, Longwen Chen, MD, PhD, and Ming Zhou, MD, PhD
Abstract: Retroperitoneal recurrence of clear cell renal cell carcinoma (CCRCC) after surgical resection is often investi- gated by needle biopsy and frequently requires immunohisto- chemistry to distinguish from other lesions with similar histology. This study explores the diagnostic utility of a panel of immunohistochemical markers and emphasizes potential pitfalls in dealing with this differential diagnosis. A tissue microarray with 1 mm tissue cores was constructed to include 21 CCRCC, 19 adrenocortical lesions, and 15 retroperitoneal or mediastinal paragangliomas. Triplicate cores were used for each case. The tissue microarray was then immunostained with epithelial, RCC, adrenocortical, and neuroendocrine markers. Pancytokeratins AE1/3, CAM5.2, and epithelial membrane antigen were positive in 52.4%, 66.7%, and 61.9% of CCRCC cases. Three (14.2%) CCRCC cases were negative for all 3 epithelial markers. AE1/3 and epithelial membrane antigen were negative in all adrenocortical lesions and paraganglioma cases, whereas CAM5.2 was positive in 78.9% of adrenocortical lesions and 6.7% of paragangliomas. RCC markers, including RCC Ag, CA9, and CD10, were positive in 76.2%, 85.7%, and 100% of CCRCC cases and were negative in all adrenocortical lesions and paragangliomas. Calretinin and Melan-A were positive in 100% and 94.7% of adrenal, 0% and 14.3% of CCRCC, and 26.7% and 26.7% of paragangliomas. Epithelial markers may be entirely negative in CCRCC, whereas pancy- tokeratin CAM5.2 is often positive in adrenocortical lesions. Furthermore, neuroendocrine markers are frequently positive in adrenocortical lesions. Therefore, a panel of, rather than single, epithelial, “CCRCC-specific,” adrenocortical and neuroendo- crine markers should be applied in the differential diagnosis of CCRCC, adrenocortical lesions, and paragangliomas.
Key Words: clear cell renal cell carcinoma, paraganglioma, adrenocortical lesion, immunohistochemistry, biopsy
(Appl Immunohistochem Mol Morphol 2010;18:414-421)
R )enal cell carcinoma (RCC) accounts for 2% to 4% of all adult malignancies, but more than 90% of malignancies involving the kidney in both males and females. The most common histologic subtype of RCC is clear cell RCC (CCRCC), accounting for 60% to 80% of RCC cases. CCRCC is well known for its tendency to metastasize. Up to one-third of patients with localized CCRCC will eventually develop local and distant recur- rence after surgical resection, after 10 years or more in some cases. Metastasis occurs most often by hematogen- ous spread although lymphatic metastasis may also occur. The most common organs involved are lung, liver, bone, soft tissue, pleura, and the adrenal glands, and a signifi- cant number of patients also develop retroperitoneal recurrence or metastasis.1-5 Because of their precarious location, the diagnosis of retroperitoneal recurrence or metastasis is often established on biopsies where only a limited amount of tissue is available for histologic examination.
CCRCC is characterized by nests of clear cells separated by arborizing thin vascular septa. How- ever, several other retroperitoneal lesions have a similar histologic appearance. For example, extra-adrenal para- gangliomas may arise anywhere in the retroperitoneum from the upper abdomen to the pelvic floor, and are often arranged in a nested, or “Zellballen,” pattern with prominent vascular septa. Tumor cells have lightly eosinophilic cytoplasm, and considerable nuclear pleo- morphism is often observed.6,7 Similarly, normal adrenal cortex and benign adrenocortical lesions are composed of small nests, cords, or alveolar collections of mostly vacuolated, foamy clear cells. The nuclei are vesicular with small but prominent nucleoli.8-12 These lesions may be difficult to distinguish from CCRCC based on histologic examination alone, especially when only a limited amount of material is available. Immunohisto- chemistry is often required as a diagnostic aid in such circumstances.
Although many immunohistochemical markers have been studied in CCRCC, paraganglioma, and adreno- cortical lesions separately, a direct comparison of these markers in a single study is not available. In addition, the diagnostic sensitivity as well as specificity of these immunohistochemical markers in the setting of limited
Received for publication January 14, 2010; accepted March 16, 2010. From the Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, OH.
Reprints: Ming Zhou, MD, PhD, Department of Anatomic Pathology, Cleveland Clinic, 9500 Euclid Avenue, L25, Cleveland, OH 44195 (e-mail: zhoum@ccf.org).
Copyright @ 2010 by Lippincott Williams & Wilkins
material is not known. This study was designed to investigate the diagnostic utility of a panel of immuno- histochemical markers in the differential diagnosis be- tween CCRCC, adrenocortical lesions, and extra-adrenal paragangliomas in the setting in which limited tissue is available to pathologists.
MATERIALS AND METHODS
This study was approved by the authors’ institu- tional review board. Twenty-one cases of CCRCC, 19 adrenal cortical lesions (12 normal cortex, 5 hyperplastic nodules, and 2 cortical adenomas), and 15 retroperitoneal or mediastinal paragangliomas were retrieved from the surgical pathology files at the authors’ institute. Fuhrman nuclear grade was 2 in 9 (42.9%), 3 in 8 (38.1%), and 4 in 4 (19.0%) CCRCC cases. The pathologic stage was pT1 in 11 (52.4%), pT2 in 3 (14.3%), and pT3 in 7 (33.3%) CCRCC cases. Slides were reviewed and the original diagnoses were confirmed in each case. One representative block from each case was chosen, and three 1.0 mm cores were taken to construct a tissue microarray. Immunohisto- chemical stains were performed on the tissue microarray with a panel of markers including epithelial markers [cytokeratin AE1/3, CAM 5.2, epithelial membrane anti- gen (EMA)], RCC markers (CD10, CA9, RCC antigen), adrenal cortical markers (calretinin, Melan-A), and neuro- endocrine markers [synaptophysin, chromogranin, CD56, neuron-specific enolase (NSE)]. The antibody source and dilution for each marker is shown in Table 1. The percentage of the cells showing positive staining was recorded for each core. An average of the percentages of positive staining in the 3 cores was then calculated for each case. A case was considered to be positive for a marker if greater than 5% of the cells were positive for that marker.
RESULTS
The percentage of cases positive for each immuno- histochemical marker, the mean percentage of cells positive for the markers in each case, and the sensitivity and specificity of each marker are listed in Tables 2 and 3. The representative images are shown in Figures 1-3.
Pancytokeratin AE1/3, CAM5.2, and EMA expres- sion was present in 11 (52.4%), 14 (66.7%), and 13 (61.9%) of 21 cases of CCRCC. Three (14.2%) cases were negative for all 3 epithelial markers. On the other hand, AE1/3 and EMA were negative in all of the adrenocortical and paraganglioma cases. CAM5.2, how- ever, was positive in 15 of 19 (78.9%) adrenocor- tical lesions and 1 of 15 (6.7%) paraganglioma cases (Fig. 2D). Although the percentage of cells positive for CAM5.2 was less in adrenocortical lesions (16.4%) than in CCRCC (31.8%), the range overlapped (0% to 35% in adrenocortical lesions and 0% to 95% in CCRCC).
RCC markers, including RCC Ag, CA9, and CD10, were positive in 16 (76.2%), 18 (85.7%), and 21 (100%) of 21 cases of CCRCC, but negative in all adrenocortical lesions and paragangliomas.
The adrenocortical marker calretinin was positive in all 19 (100%) adrenocortical lesions and 4 (26.7%) paragangliomas, but was negative in all 21 CCRCC. Another adrenocortical marker, Melan-A, was positive in 18 (94.7%) adrenocortical lesions, 3 (14.3%) cases of CCRCC, and 4 (26.7%) paragangliomas.
Two of the neuroendocrine markers, synaptophysin and CD56, were positive in all of the paraganglioma cases, but were also positive in the majority of adreno- cortical lesions (Table 1). CD56 was positive in 1 of 21 (4.8%) CCRCC, whereas synatophysin was negative in CCRCC. A third marker, chromogranin, was positive in a minority of paragangliomas, CCRCC, and adreno- cortical lesions. NSE, in contrast, was positive in all of the paragangliomas and CCRCC, and in the majority of adrenocortical lesions.
The sensitivity and specificity of the epithelial and RCC markers for CCRCC, the adrenocortical markers for adrenocortical lesions, and the neuroendocrine mar- kers for paragangliomas are summarized in Table 3. Epithelial markers, including AE1/3 and EMA, and RCC markers, including RCC Ag, CA9, and CD10, had a sensitivity of 52% to 100% and specificity of 100% for the diagnosis of CCRCC. CD10 in particular had a 100% sensitivity and specificity. However, CAM5.2 had a
| TABLE 1. Antibody Sources and Dilutions | |||
|---|---|---|---|
| Immunohistochemical Markers | Antibody Source | Dilution | |
| Epithelial | AE 1/3 | Millipore/mab3412 Billerica, MA | 1:200 |
| CAM 5.2 | Becton Dickinson/349205 Franklin Lakes, NJ | 1:10 | |
| EMA | Dako/M0613 Dako, Denmark | 1:50 | |
| RCC | RCC Ag | Ventana/760-4273 Tucson, AZ | Prediluted |
| CA9 | Novus Biologicals/NB100-417 Littleton, CO | 1:400 | |
| CD10 | Novocastra/NCL-CD10-270 New Castle upon Tyne, UK | 1:5 | |
| Adrenal cortical | Calretinin | Invitrogen/08-1211 Carlsbad, CA | 1:40 |
| Melan-A | Biogenex/MU361-UC San Ramon, CA | 1:20 | |
| Neuroendocrine | Synaptophysin | Dako/A010 Dako, Denmark | 1:20 |
| Chromogranin | Dako/M0869 Dako, Denmark | 1:100 | |
| CD56 | Novocastra/NCL-CD56-1B6 New Castle upon Tyne, UK | 1:200 | |
| NSE | Dako/M0873 Dako, Denmark | 1:50 | |
EMA indicates epithelial membrane antigen; RCC, renal cell carcinoma.
| TABLE 2. Expression of Immunohistochemical Markers in CCRCC, Paraganglioma, and Adrenocortical Lesions | ||||||
|---|---|---|---|---|---|---|
| Immunohistochemical Markers | CCRCC | Adrenal Cortex | Paraganglioma | |||
| Number (%) + Cases | % + Cells Mean (Range) | Number (%) + Cases | % + Cells Mean (Range) | Number (%) + Cases | % + Cells Mean (Range) | |
| Epithelial | ||||||
| AE 1/3 | 11/21 (52.4) | 43.0% (0-100) | 0/19 (0) | 0.1% (0-2) | 0/15 (0) | 0 (0) |
| CAM 5.2 | 14/21 (66.7) | 31.8% (0-95) | 15/19 (78.9) | 16.4% (0-35) | 1/15 (6.7) | 0.3% (0-5) |
| EMA | 13/21 (61.9) | 16.8% (0-83) | 0/19 (0) | 0 (0) | 0/15 (0) | 0 (0) |
| RCC | ||||||
| RCC Ag | 16/21 (76.2) | 27.9% (0-83) | 0/19 (0) | 0 (0) | 0/15 (0) | 0 (0) |
| CA9 | 18/21 (85.7) | 70.6% (0-100) | 0/19 (0) | 0 (0) | 0/15 (0) | 0 (0) |
| CD10 | 21/21 (100) | 70.6% (8-100) | 0/19 (0) | 0.05% (0-1) | 0/15 (0) | 0 (0) |
| Adrenal cortical | ||||||
| Calretinin | 0/21 (0) | 0 (0) | 19/19 (100) | 90.3% (48-100) | 4/15 (26.7) | 17.5% (0-90) |
| Melan-A | 3/21 (14.3) | 11.3% (0-90) | 18/19 (94.7) | 83.6% (0-100) | 4/15 (26.7) | 18.3% (0-88) |
| Neuroendocrine | ||||||
| Synapto-physin | 0/21 (0) | 0 (0) | 14/19 (73.7) | 34.3% (0-85) | 15/15 (100) | 92.2% (62-100) |
| Chromo-granin | 2/21 (9.5) | 4.0% (0-50) | 5/19 (26.3) | 5.4% (0-37) | 6/16 (40.0) | 26.7% (0-88) |
| CD56 | 1/21 (4.8) | 0.3% (0-7) | 18/19 (94.7) | 33.6% (3-77) | 15/15 (100) | 81% (10-100) |
| NSE | 21/21 (100) | 76% (5-100) | 18/19 (94.7) | 44.5% (0-83) | 15/15 (100) | 93.5% (76-100) |
| CCRCC indicates clear cell renal cell carcinoma; EMA, epithelial membrane antigen; RCC, renal cell carcinoma. | ||||||
sensitivity of 67% and specificity of 56% for the diag- nosis of CCRCC. The sensitivities of the adrenocortical markers calretinin and Melan-A for the diagnosis of adrenocortical lesions were 100% and 95%, respectively, and their specificities were 89% and 81%, respectively. The sensitivity of neuroendocrine markers for paragan- gliomas ranged from 40% to 100%, and the specificity ranged from 2.5% to 82.5%.
DISCUSSION
Retroperitoneal recurrence of CCRCC after surgi- cal treatment is not uncommon. It is critical to confirm the diagnosis and rule out other lesions that arise in the same anatomic locations and may occasionally be
mistaken for recurrent CCRCC, including adrenocortical lesions and retroperitoneal paragangliomas. The mor- phologic similarities between CCRCC and adrenocortical lesions or paragangliomas impose diagnostic difficulties. This problem is confounded by the limited amount of tissue obtained from needle core biopsy or needle aspiration cytology to establish a correct diagnosis in many cases. A panel of immunohistochemical markers is often relied upon to make a distinction among the above- mentioned lesions. However, data regarding the sensitiv- ity and specificity of these markers on limited biopsy material is lacking.
In this study, we used a panel of immunohisto- chemical stains to stain tissue cores from cases of CCRCC, paragangliomas, and adrenocortical lesions
| Immunohistochemical Markers | CCRCC | Adrenal Cortical Lesion | Paraganglioma | |||
|---|---|---|---|---|---|---|
| Sensitivity (%) | Specificity (%) | Sensitivity (%) | Specificity (%) | Sensitivity (%) | Specificity (%) | |
| Epithelial | ||||||
| AE 1/3 | 11/21 (52.4) | 34/34 (100) | ||||
| CAM 5.2 | 14/21 (66.7) | 19/34 (55.9) | ||||
| EMA | 13/21 (61.9) | 34/34 (100) | ||||
| RCC | ||||||
| RCC antigen | 16/21 (76.2) | 34/34 (100) | ||||
| CA9 | 18/21 (85.7) | 34/34 (100) | ||||
| CD10 | 21/21 (100) | 34/34 (100) | ||||
| Adrenal cortical | ||||||
| Calretinin | 19/19 (100) | 32/36 (88.9) | ||||
| Melan-A | 18/19 (94.7) | 29/36 (80.6) | ||||
| Neuroendocrine | ||||||
| Synaptophysin | 15/15 (100) | 26/40 (65.0) | ||||
| Chromogranin | 6/16 (40.0) | 33/40 (82.5) | ||||
| CD56 | 15/15 (100) | 21/40 (52.5) | ||||
| NSE | 15/15 (100) | 1/40 (2.5) | ||||
CCRCC indicates clear cell renal cell carcinoma; EMA, epithelial membrane antigen; RCC, renal cell carcinoma.
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and investigated the sensitivity and specificity of these markers in the setting of limited tissue. In contrast to other published studies that employed large tissue sections, a tissue microarray with 1 mm tissue cores was
constructed to simulate the limited biopsy tissue usually available in this clinical setting. We selected those immunomarkers that are commonly used and well validated in our laboratory.
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Our findings, for the most part, were consistent with previous findings in the literature regarding the staining patterns of these markers in CCRCC, adrenocortical lesions, and paragangliomas.13 48 Specifically, the major- ity of CCRCC stains positively with RCC antigen, CA9, and CD10, and more than half the cases show positive staining with epithelial markers such as AE1/3, CAM 5.2, and EMA. By contrast, the adrenocortical lesions did not stain for RCC antigen, CA9, CD10, AE1/AE3, and EMA. They stained positively for calretinin and Melan-A, as well as the neuroendocrine markers, including synapto- physin, CD56, and NSE in a majority of cases. Most of the paragangliomas did not stain with the epithelial markers and RCC-related markers. They stained posi- tively with most of the neuroendocrine markers but were also positive for calretinin and Melan-A in one-fourth of cases.
However, this study highlights 2 important issues when applying immunohistochemistry to limited tissue in the differential diagnosis of CCRCC, adrenocortical
lesions, and paragangliomas. The first issue is the lack of expression of epithelial markers in some CCRCC cases and the presence of CAM 5.2 expression in the majority of adrenocortical lesions. Presence of the epithelial markers is often used as the evidence to support a diagnosis of CCRCC, and vice versa. However, one has to be aware that AE1/3, CAM 5.2, and EMA are not present in 100% CCRCC cases. They are detected in 52.4%, 66.7%, and 61.9% of CCRCC cases, respectively. Although 85.8% of CCRCC cases were positive for at least one of these epithelial markers, 3 (14.2%) cases were negative for all 3 markers. In contrast, CAM 5.2 was positive in 89.5% of adrenocortical lesions. Therefore CAM 5.2 should be avoided when choosing an epithelial marker to differentiate between CCRCC and adrenocortical lesions. Other epithe- lial markers including AE1/3 and EMA could be used as they are negative in adrenocortical lesions, although their diagnostic sensitivities were only 52.4% and 61.9%. “CCRCC-specific” markers, including RCC Ag, CA9, and CD10, are better markers in the differential diagnosis
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between CCRCC and adrenocortical lesions, as they demon- strate higher sensitivity (76.2%, 85.7%, and 100%, respec- tively) than the epithelial markers, and 100% specificity. CD10 is particularly well suited for this purpose, as its sensitivity and specificity are both 100%.
The second issue is the frequent expression of neuroendocrine markers in adrenocortical lesions. Neuro- endocrine markers are used to confirm the presence of neuroendocrine differentiation in tumors such as paragan- gliomas. Indeed, synaptophysin, chromogranin, CD56, and
NSE were positive in 100%, 40%, 100%, and 100% of paragangliomas, respectively. But they were also frequently positive in adrenocortical lesions (73.7%, 26.3%, 97.4%, and 94.7%, respectively). Therefore, these neuroendocrine markers should not be used in the differential diagnosis of adrenocortical lesions and pheochromocytoma or para- gangliomas on limited tissue. Instead, our results suggest that adrenocortical markers such as calretinin and Melan-A should be used, as these 2 markers were positive in 100% and 94.7% of adrenocortical lesions, but positive only in 26.7% and 26.7% of paragangliomas.
Inhibin is another well-characterized adrenocortical marker. It was not examined in our study as the stain was not available in our laboratory owing to technical reasons. In the literature, inhibin was expressed in 73% to 100% of adrenocortical lesions, 0% of CCRCC, and 16% of paragangliomas.49-53 The expression of inhibin in CCRCC, adrenocortical lesions, and paragangliomas seems similar to that of calretinin in our report.
This report compared, in a single study, the diag- nostic sensitivity and specificity of multiple immuno- histochemical markers, all commonly used in daily practice, for differential diagnosis between CCRCC, adrenocorti- cal lesions, and paraganglioma in the setting of limited biopsy material. Our findings are significant in that CAM5.2 should be avoided in the differential diagnoses of CCRCC and adrenocortical lesions, and neuro- endocrine markers should be avoided in the differential diagnoses of adrenocortical lesions and paragangliomas. As the distinction among these lesions often requires the use of immunohistochemical markers, selecting “wrong” markers may result in erroneous interpretation. These findings, to our knowledge, have not been emphasized in the literature.
In summary, there are several potential pitfalls when using immunomarkers in the differential diagnosis of CCRCC, adrenocortical lesions, and paragangliomas in the setting of limited biopsy material. The epithelial markers may be entirely negative in CCRCC whereas pancytokeratin CAM5.2 is positive in the majority of adrenocortical tissue. Furthermore, neuroendocrine mar- kers are frequently positive in adrenocortical tissue. Therefore, a panel of epithelial, CCRCC-specific, adre- nocortical, and neuroendocrine immunohistochemical markers, rather than a single marker, should be applied in the differential diagnosis of CCRCC, adrenocortical lesions, and paragangliomas. CAM5.2 should be avoided in the setting of CCRCC versus adrenocortical lesions and neuroendocrine makers should be avoided in the setting of paraganglioma versus adrenocortical lesions.
REFERENCES
1. Eble JN, Togashi K, Pisani P. Renal cell carcinoma. In: Eble JN, Sauter G, Epstein JI, et al, eds. World Health Organization Classification of Tumours: Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs. Lyon, France: IARC Press; 2004:12-14.
2. Mancini V, Battaglia M, Ditonno P, et al. Current insights in renal cell cancer pathology. Urol Oncol. 2008;26:225-238.
3. Ng CS, Wood CG, Silverman PM, et al. Renal cell carcinoma: diagnosis, staging, and surveillance. AJR Am J Roentgenol. 2008; 191:1220-1232.
4. Grignon DJ, Eble JN, Bonsib SM, et al. Clear cell renal cell carcinoma. In: Eble JN, Sauter G, Epstein JI, et al, eds. World Health Organization Classification of Tumours: Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs. Lyon, France: IARC Press; 2004:23-25.
5. Reuter VE, Tickoo SK. Adult renal tumors. In: Mills SE, ed. Sternberg’s Diagnostic Surgical Pathology. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2004:1863-1954.
6. Lack EE. Paragangliomas. In: Mills SE, ed. Sternberg’s Diagnostic Surgical Pathology. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2004:669-696.
7. Kliewer KE, Cochran AJ. A review of the histology, ultrastructure, immunohistology, and molecular biology of extra-adrenal para- gangliomas. Arch Pathol Lab Med. 1989;113:1209-1218.
8. DeLellis RA, Mangray S. The adrenal glands. In: Mills SE, ed. Sternberg’s Diagnostic Surgical Pathology. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2004:621-668.
9. Lack EE, Wieneke JA. Adrenal glands. In: Bostwick DG, ed. Urologic Surgical Pathology. 2nd ed. Philadelphia, PA: Mosby- Elsevier; 2008:953-1008.
10. Wenig BM. Pathology of the adrenal gland. In: Tannenbaum M, ed. Diagnostic Atlas of Genitourinary Pathology. Philadelphia, PA: Church hill-Livingstone-Elsevier; 2006:385-398.
11. Lack EE. Tumors of the adrenal gland and extra-adrenal paraganglia. In: Lack EE, ed. Atlas of Tumor Pathology, 3rd Series, Fascicle 19. Washington, DC: Armed Forces Institute of Pathology; 1997:49-152.
12. Rosai J. Adrenal gland and other paraganglia. In: Rosai J, ed. Surgical Pathology. Philadelphia, PA: Mosby; 2004:1115-1162.
13. Zhou M, Roma A, Magi-Galluzzi C. The usefulness of immuno- histochemical markers in the differential diagnosis of renal neoplasms. Clin Lab Med. 2005;25:247-257.
14. Wu SL, Kothari P, Wheeler TM, et al. Cytokeratins 7 and 20 immunoreactivity in chromophobe renal cell carcinomas and renal oncocytomas. Mod Pathol. 2002;15:712-717.
15. McGregor DK, Khurana KK, Cao C, et al. Diagnosing primary and metastatic renal cell carcinoma: the use of the monoclonal antibody “renal cell carcinoma marker.” Am J Surg Pathol. 2001;25:1485-1492.
16. Avery AK, Beckstead J, Renshaw AA, et al. Use of antibodies to RCC and CD10 in the differential diagnosis of renal neoplasms. Am J Surg Pathol. 2000;24:203-210.
17. Ordonez NG. The diagnostic utility of immunohistochemistry in distinguishing between mesothelioma and renal cell carcinoma: a comparative study. Hum Pathol. 2004;35:697-710.
18. Kim MK, Kim S. Immunohistochemical profile of common epithelial neoplasms arising in the kidney. Appl Immunohistochem Mol Morphol. 2002;10:332-338.
19. Dai L, Lu XH, Li ZH, et al. Value of special stains and immuno- histochemistry in the diagnosis of renal epithelial neoplasms. Zhonghua Bing Li Xue Za Zhi. 2004;33:140-142.
20. Yang B, Ali SZ, Rosenthal DL. CD10 facilitates the diagnosis of metastatic renal cell carcinoma from primary adrenal cortical neoplasm in adrenal fine-needle aspiration. Diagn Cytopathol. 2002; 27:149-152.
21. Gokden N, Mukunyadzi P, James JD, et al. Diagnostic utility of renal cell carcinoma marker in cytopathology. Appl Immunohisto- chem Mol Morphol. 2003;11:116-119.
22. Langner C, Wegscheider BJ, Ratschek M, et al. Keratin immuno- histochemistry in renal cell carcinoma subtypes and renal onco- cytomas: a systematic analysis of 233 tumors. Virchows Arch. 2004; 444:127-134.
23. Young AN, Amin MB, Moreno CS, et al. Expression profiling of renal epithelial neoplasms: a method for tumor classification and discovery of diagnostic molecular markers. Am J Pathol. 2001;158: 1639-1651.
24. Miliaris D, Karasavvidou F, Papanikolau A, et al. KIT expression in fetal, normal adult, and neoplastic renal tissues. J Clin Pathol. 2004;57:463-466.
25. Langner C, Ratschek M, Rehak P, et al. Expression of MUC1 (EMA) and E-cadherin in renal cell carcinoma: a systematic immunohisto- chemical analysis of 188 cases. Mod Pathol. 2004;17:180-188.
26. Chu P, Wu E, Weiss LM. Cytokeratin 7 and cytokeratin 20 expression in epithelial neoplasms: a survey of 435 cases. Mod Pathol. 2000;13:962-972.
27. Skinnider BF, Amin MB. An immunohistochemical approach to the differential diagnosis of renal tumors. Semin Diagn Pathol. 2005;22: 51-68.
28. Saeger W. Pathology of adrenal neoplasms. Minerva Endocrinol. 1995;20:1-7.
29. McNicol AM. Lesions of the adrenal cortex. Arch Pathol Lab Med. 2008;132:1263-1271.
30. Sasano H, Suzuki T, Moriya T. Recent advances in histopathology and Immunohistochemistry of adrenocortical carcinoma. Endocr Pathol. 2006;17:345-354.
31. Giordano TJ. Molecular pathology of adrenal cortical tumors: separating adenomas from carcinomas. Endocr Pathol. 2006;17: 355-364.
32. Schroder S, Niendorf A, Achilles E, et al. Immunocytochemical differential diagnosis of adrenocortical neoplasms using the mono- clonal antibody D11. Virchows Arch A Pathol Anat Histopathol. 1990;417:89-96.
33. Komminoth P, Roth J, Schroder S, et al. Overlapping expression of immunohistochemical markers and synaptophysin mRNA in pheochromocytomas and adrenocortical carcinomas: implications for the differential diagnosis of adrenal gland tumors. Lab Invest. 1995;72:424-431.
34. Ghorab Z, Jorda M, Ganjei P, et al. Melan A (A103) is expressed in adrenocortical neoplasms but not in renal cell and hepatocellular carcinomas. Appl Immunohistochem Mol Morphol. 2003;11:330-333.
35. Haak HR, Fleuren GJ. Neuroendocrine differentiation of adreno- cortical tumors. Cancer. 1995;75:860-864.
36. Chu PG, Weiss LM. Keratin expression in human tissues and neoplasms. Histopathology. 2002;40:403-439.
37. Kimura N, Nakazato Y, Nagura H, et al. Expression of intermediate filaments in neuroendocrine tumors. Arch Pathol Lab Med. 1990;114:506-510.
38. Fraga M, Garcia-Caballero T, Antunez J, et al. A comparative immunohistochemical study of phaeochromocytomas and paragan- gliomas. Histol Histopathol. 1993;8:429-436.
39. Miettinen M. Neuroendocrine differentiation in adrenocortical carcinoma. New immunohistochemical findings supported by electron microscopy. Lab Invest. 1992;66:169-174.
40. Busam KJ, Iversen K, Coplan KA, et al. Immunoreactivity for A103, an antibody to melan-A (Mart-1), in adrenocortical and other steroid tumors. Am J Surg Pathol. 1998;22:57-63.
41. Loy TS, Phillips RW, Linder CL. A103 immunostaining in the diagnosis of adrenal cortical tumors: an immunohistochemical study of 72 neoplasms. Arch Pathol Lab Med. 2002;126:170-172.
42. Schroder S, Padberg BC, Achilles E, et al. Immunocytochemistry in adrenocortical tumours: a clinicomorphologic study of 72 neoplasms. Virchows Arch Pathol Anat Histopathol. 1992;420:65-70.
43. Lloyd RV, ed. Endocrine Pathology: Differential Diagnosis and Molecular Advances. Totowa, New Jersey: Humana Press; 2004.
44. Erickson LA, Lloyd RV. Practical markers used in the diagnosis of endocrine tumors. Adv Anat Pathol. 2004;11:175-189.
45. McNicol AM. Histopathology and Immunohistochemistry of adrenal medullary tumors and paragangliomas. Endocr Pathol. 2006;17:329-336.
46. Ellison DA, Parham DM. Tumors of the autonomic nervous system. Am J Clin Pathol. 2001;115(suppl 1):S46-S55.
47. Wasserman PG, Savargaonkar P. Paragangliomas: classification, pathology, and differential diagnosis. Otolaryngol Clin North Am. 2001;34:845-862, v-vi.
48. Wick MR. Immunohistology of neuroendocrine and neuroectoder- mal tumors. Semin Diagn Pathol. 2000;17:194-203.
49. Arola J, Liu J, Heikkila P, et al. Expression of inhibin a in adrenocortical tumours reflects the hormonal status of the neoplasm. J Endocrinol. 2000;165:223-229.
50. Munro LMA, Kennedy A, McNicol AM. The expression of inhibin/ activin subunits in the human adrenal cortex and its tumours. J Endocrinol. 1999;161:341-347.
51. Zhang PJ, Genega EM, Tomaszewski JE, et al. The role of calretinin, inhibin, melan-A, bcl-2, and c-kit in differentiating adrenal cortical and medullary tumors: an immunohistochemical study. Mod Pathol. 2003;16:591-597.
52. Cho EY, Ahn GH. Immunoexpression of inhibin o-subunit in adrenal neoplasms. Appl Immunohistochem Mol Morphol. 2001;9:222-228.
53. Hoang MP, Amirkhan RH. Inhibin alpha distinguishes hemangio- blastoma from clear cell renal cell carcinoma. Am J Surg Pathol. 2003;27:1152-1156.