Oncocytic Adreno Cortical Tumors: Pathological Features of 16 Cases and Review of the Literature
Yeşim Ertan,ª Asuman Argon,b,* Murat Özdemir,” Banu Pınar Şarer Yürekli,d Zafer Dökümcü,e & Özer Makayc
aDepartment of Pathology, Ege University, Izmir, Turkey; bDepartment of Pathology, Izmir Bozyaka Training and Research Hospital, Izmir, Turkey; “Department of General Surgery, Ege University, Izmir, Turkey; dDepartment of Endocrinology, Ege University, Izmir, Turkey; eDepartment of Pediatric Surgery, Ege University, Izmir, Turkey
*Address all correspondence to: Dr. Asuman Argon, Department of Pathology, Izmir Bozyaka Training and Research Hospital, Izmir, Turkey; Tel .: +90 2322505050- 2271; Fax: +90 2322502997, E-mail: asumanargon@gmail.com
ABSTRACT: Oncocytic neoplasms of the adrenal gland are extremely rare tumors. These tumors differ from their nononcocytic counterparts in some respects. The aim of this study was to review and discuss the clinical, histological, and immunohistochemical features of as well as the prognosis for these rare tumors.
In total, 16 cases diagnosed as adrenocortical oncocytic neoplasms between January 2011 and December 2016 were included in the study. The demographic data, gross characteristics, histological data, and immunohistochemical data (Chromogranin-A, Synaptophysin, a-İnhibin, Melan-A, Ki67, PHH3) were reevaluated. The follow-up data for these patients were added in January 2017.
Of the 16 cases, 12 were adrenocortical adenoma, 1 was borderline adrenocortical tumor, and 3 were adreno- cortical carcinoma. The tumors equally affected both genders. The tumors were not generally large. Tumor cells had pleomorphic nuclei in ten cases, but it was more obvious in one case. The mitotic figure count was low in most tumors. Atypical mitosis and necrosis were observed in three and four tumors, respectively. None of cases included sinusoidal invasion, vascular invasion, or capsular invasion. We detected the expression of at least one specific marker (e.g., Melan-A, Inhibin-a) of the adrenal cortex in all tumors. None of the tumors were immunoreactive for Chromogranin- A. Ki-67 proliferation index was lower than 5% in all cases except three oncocytic carcinomas. In two cases, PHH3 positivity was not seen, while it was lower than 3 of 10 high-powered fields in ten cases and higher in 4 cases. All patients were alive and disease free except for two patients with adrenocortical carcinoma.
In conclusion, determining the clinical, histological, and immunohistochemical characteristics of these extremely rare tumors can provide important information for early diagnosis, treatment, and follow-up of these cases.
KEY WORDS: oncocytic adrenocortical tumor, oncocytoma, adrenal cortical tumor, adrenal cortical tumor with uncertain malignant potential, pediatric adrenocortical tumor.
I. INTRODUCTION
Oncocytic tumors are neoplasms composed predom- inantly of cells with abundant granular, eosinophilic cytoplasm termed “oncocytes.” The mentioned cy- toplasmic changes are attributed to the abundantly existing mitochondria that can be determined by the electron microscope.1 Oncocytic tumors have been mentioned in various organs such as kidneys, ad- renals, thyroid, parathyroid, pituitary, and salivary glands.2 Oncocytic neoplasms of the adrenal gland are extremely rare tumors and may be classified into three major categories: oncocytomas, oncocytic
neoplasm of uncertain malignant potential, and on- cocytic carcinoma.3 Since the first description of these tumors, few cases have been reported, either in the form of single case or as a small series.4-5
All oncocytic adrenocortical tumors (OACTs) have some of the classical Weiss parameters6 (Table 1), such as eosinophilic cytoplasm, nuclear atypia, and diffuse growth pattern. Moreover, these features are present in the vast majority of cases, irrespec- tive of their biological and clinical behavior. As a Weiss score 3 can be easily attained because of these morphological features, at least a proportion of such cases may be overdiagnosed as carcinomas.
TABLE 1: Weiss histopathological scoring system
Nuclear grade (III or IV)
Mitotic rate; > 5/50 HPF (x40 objective)
Atypical mitotic figures
Cytoplasm; ≤ 25% clear or vacuolated cells
Diffuse architecture
Necrosis Venous invasion Sinusoidal invasion
Invasion of tumor capsule
Note: Presence of 3 or more criteria is related to malignancy
The aim of this retrospective study was to re- view and discuss the clinical, histological, and im- munohistochemical features of and prognosis for adrenal oncocytic neoplasms.
II. MATERIALS AND METHODS
A. Case Selection and Histomorphological Analysis
All the cases with adrenalectomy were retrieved from electronic database of the Department of Pathology of a referral university hospital. Of the 312 adrenal- ectomy specimens operated for a mass lesion, 16 with adrenocortical oncocytic neoplasms between 2011 and 2016 were included in the study. Hema- toxylin-eosin-stained sections of all cases were re- evaluated by pathologists, and clinicopathological findings were recorded regarding demographics (age, sex), gross characteristics (size, necrosis), and histological features (pleomorphism, intranuclear in- clusion, mitosis and atypical mitosis, and presence of sinusoidal, vascular, or capsular invasion). Mitoses were counted in 50 high-power fields (HPF) in areas with the highest proliferative activity and expressed as the number of mitoses in 50 HPF.
All cases were classified as adrenal cortical adenoma (ACA), adrenal cortical tumor with un- certain malignant potential (borderline ACT), or adrenocortical carcinoma (ACC), based on crite- ria of Lin-Weiss-Bisceglia6 for adult patients and Wienecke criteria7 for pediatric patients. Lin- Weiss-Bisceglia and Wienecke criteria are shown
in Table 2 and Table 3.
B. Immunohistochemistry
Immunohistochemical (IHC) analyses were per- formed on 4-um-thick sections obtained from se- lected blocks that reflected most of the histological features of the tumor. Immunohistochemical stain- ing for Chromogranin-A (Ventana, Clone LK2H10, ready-to-use), Synaptophysin (Leica, Clone Syn- apto-299, 1:100 dilution), Inhibin-a (Cell morque; monoclonal, ready-to-use), Melan-A (Cell morque, clone A103, diluted 1/100), Ki67 (Dako, clone MIB-1, diluted 1/100), PHH3 (Cell morque, Poly- clonal, ready-to-use) antibodies were performed on the Ventana Autostainer. Cytoplasmic staining for Chromogranin-A, Synaptophysin, Inhibin a, Melan-A and nuclear staining for PHH3, Ki67 were considered positive. For Ki67 and PHH3, at least 50 HPF were evaluated for each tumor in hot spots.
C. Demographic and Survival Data
The clinical features of the cases and the gross char- acteristics of the tumors were obtained from the ar- chive system of our hospital. The prognostic infor- mation was obtained from the archive records of the local cancer monitoring and follow-up center. Sur- vival time was calculated from the date of resection to the date of death or to the date of the latest follow- up. The follow-up data of the patients were added in January 2017. We followed the Declaration of Helsinki on medical protocol and ethics in this study.
TABLE 2: Lin-Weiss-Bisceglia criteria for assessing the malignant potential of oncocytic adrenal neoplasms
Major criteria Mitotic rate > 5 per 50 HPF Atypical mitotic figures Venous invasion
Minor criteria Size > 10 cm and/or weight >200 g Microscopic necrosis Capsular invasion Sinusoidal invasion
TABLE 3: Proposed criteria for malignancy of adrenocortical neoplasms in pediatric patients
Tumor weight of > 400 g Tumor size > 10.5 cm
Extension into periadrenal soft tissues and/or adjacent organs Invasion into vena cava Venous invasion Capsular invasion Presence of tumor necrosis > 15 mitoses per 20 high-power fields Presence of atypical mitotic figures
Note: The presence of up to two criteria is associated with benign outcome; three criteria are considered indeterminate for malignancy; and four or more criteria are associated with malignancy
III. RESULTS
A. Demographic and Histomorphological Analysis
Of the 312 adrenalectomy specimens operated for mass lesion, 68 (21.79%) had ACA; 3 (0.96%) had borderline ACT; and 8 (2.56%) had ACC. More- over, 12 of the ACAs (17.64%), 1 of the borderline ACTs (33.33%), and 3 of the ACCs (37.50%) had predominant oncocytic cells (composed of at least 90% oncocytes). All 16 tumors with oncocytic fea- tures were included in this study.
Both genders were equally affected (male/fe- male: 8/8). A median age was 37.50 years (range, 1-62 years). The tumors were not generally large, with a mean diameter of 5.13 ± 4.19 cm (range, 1-19 cm). Necrosis was seen in only four tumors.
The microscopic appearance of the tumors in- cluded cells with eosinophilic and granular cyto-
plasm arranged in solid and/or trabecular patterns. Tumor cells had pleomorphic nuclei in ten cases, and one of the cases had more obvious pleomor- phic nuclei (Fig. 1). All of the tumors consisted of cells with intranuclear inclusion at least focally, except two tumors. The mitotic figures were low in most of the tumors, and median was 1/50 HPF (range, 1-15) (Fig. 2). Atypical mitosis was ob- served in all carcinomas.
In addition, clear cell composition was seen in one of the cases. Focal adenomatous and myeloli- pomatous component were also seen in one case. None of the cases included sinusoidal, vascular or capsular invasion. The histopathological features of the tumors are listed in Table 4.
B. Immunohistochemistry
In total, 14 tumors were immunoreactive for syn- aptophysin; 12 tumors were immunoreactive for
| (≥ 6/50 HPF) Mitotic count | Atypical mitosis | Venous invasion | (≥ 10 cm) Large size | Necrosis | Capsular invasion | Sinusoidal invasion | Nuclear pleomor- phism | |
|---|---|---|---|---|---|---|---|---|
| Benign (n = 12) | 11/12 | 11/12 | 0/12 | 0/12 | 0/12 | 0/12 | 0/12 | 6*/12 |
| Borderline (n = 1) | 0/1 | 0/1 | 0/1 | 1/1 | 1/1 | 0/1 | 0/1 | 1/1 |
| Malignant (n = 3) | 3/3 | 2/3 | 0/3 | 0/3 | 3/3 | 0/3 | 0/3 | 3/3 |
*Pediatric patient
*One of six was a pediatric patient
Melan-A; and 5 tumors were immunoreactive for Inhibin-a. Although at least one specific marker (e.g., Melan-A, Inhibin-a) of the adrenal cortex was positive in all tumors, Chromogranin-A was negative. Ki-67 proliferation index was lower than 5% in all cases except three. In these three cases, it was 10%, 30%, and 40%, respectively. Immu- noreactivity of PHH3 was correlated with num- ber of mitotic figures. In 2 cases, PHH3 positivity was not seen, while it was lower than 2/10 HPF in 10 cases. In four cases with high mitotic figures, PHH3 positivity was observed in 10 cells/50 HPF, 12 cells/50 HPF, 13 cells/50 HPF and 15 cells/50 HPF, respectively.
C. Prognosis
We obtained follow-up information for 14 patients; 11 of these had ACA, and the other 3 had ACC. All patients were alive with disease free, except two of the ACC cases. The mean survival time was 27.66 ± 18.31 months. The patients died of disease at the end of the third month and fourth month, respec- tively. The other patient with ACC was alive for 24 months.
IV. DISCUSSION
There are only a few retrospective studies discuss- ing the clinical and diagnostic features of onco-
cytic neoplasms of the adrenal due to the rarity of the disease.46 The true incidence of ACAs is unknown.8 In autopsy series, the prevalence has ranged from 1.5% to 7%.9 ACAs are more rare.11 In the present study, in adrenalectomy specimens performed for mass, the rate of ACAs, border- line ACTs, and ACCs was 21.74%, 0.96%, and 2.88%, respectively. For OACTs, no information was available regarding the incidence or the rate of these tumors in English-language literature. In the present study, OACTs accounted for 5.12% of all adrenal masses and 20.25% of all adrenal cortical tumors. Overall, 17.64% of the ACAs, 33.33% of the borderline ACTs, and 37.50% of the ACC had predominant oncocytic cells. Although the propor- tion of OACTs was low among all adrenal masses and ACAs, they were more than 33% of borderline ACTs and ACCs. This result may support an as- sociation between oncocytic cells and malignancy.
To date, almost 150 OACTs have been re- ported. Their occurrence in all ages has been de- scribed, without a precise age distribution (mean age at diagnosis 47 years; range 27-72 years), and they have been observed to occur more frequently in females.5-8 In our study, there was no differ- ence between the genders, and the median age was 37.50 years. The number of our cases was small, and both of the pediatric cases were younger than 6 years; these factors may explain this difference.
As known, adrenal cortical tumors can be seen
in pediatric patients. For pediatric patients, an av- erage age is 4.6 years, and half of the patients are diagnosed in the first 4 years of life.11 Our series included two patients in the pediatric group, one of whom was 1 year old and the other was 6 years old, similar to the literature.
According to both Weiss9 and Lin-Weiss- Bisceglia6 criteria, high mitosis count and atypical mitosis were described as associated with malig- nancy. However, Blanes et al.13 emphasized that mitotic figure variability was as important as the number of mitoses in adrenocortical proliferative lesions. Heterogeneity of proliferation has been reported hallmark of malignant transformation in the adrenal cortex.10 We did not notice significant mitotic variability in our series, probably due to the small number of ACCs and because the vast majority of cases contained 1 or 2 mitoses per 50 HPF. We detected a relationship between high mi- totic count, atypical mitosis, and malignancy in our series, as in the literature.6,7,9
Although the mitotic rate was higher in ACAs, it was low in both ACAs and borderline ACTs. Moreover, all ACCs and one pediatric ACA had atypical mitotic figures. As is the case with con- ventional adrenal cortical tumors, we concluded that the mitosis in OACTs is also a feature that needs to be researched carefully.
Ability to invade tissues, a hallmark of ma- lignancy, is a complex multistep process includ- ing loosening of cell-cell contacts, degradation of extracellular matrix (ECM), attachment to novel ECM components, and migration of tumor cells.11,12 In the present study, sinusoidal invasion, or capsular invasion (defined as minor criteria) and venous invasion were not observed in any of the ACAs or borderline ACTs. In addition, these features were not observed in ACCs. According to TNM classification,11 all ACCs were stage I or II. Although there were only three ACCs in this study, we think that early detection of cortical tumors may be important. Furthermore, if there is inva- sion in OACT, other malignancy criteria should be sought persistently, but importantly, the absence of this finding does not exclude malignancy.
Immunohistochemistry is usually used to dis-
tinguish adrenocortical carcinomas from renal cell carcinoma and hepatocellular carcinoma, adrenal medullary tumors, and metastatic tumors.11 In addi- tion, Ki-67 and PHH3 can be used for distinguish- ing carcinoma versus adenoma.13 We detected the expression of at least one specific marker (e.g., Melan-A, Inhibin-a) of the adrenal cortex in all tu- mors in our series. In addition, Chromogranin-A was invariably negative in all tumors. PHH3 im- munoreactivity was correlated with number of mi- totic figures. Ki-67 proliferation index was lower than 5% in all cases except three ACC cases. These three cases were evaluated as carcinoma because of high mitotic count, presence of atypical mito- sis. Interestingly, in a tumor in which the number of mitoses was 10/50 BBA, the Ki67 proliferation rate was 3%. This tumor belonged to a 1-year-old patient who remained alive 48 months later. In the pediatric groups, evaluation and grading of adre- nocortical tumors are different from the adult pa- tients. The most important point for malignancy is the presence of only one major Lin-Weiss-Bisceg- lia criteria such as high mitotic count, atypical mi- tosis, or venous invasion in adults.6,9,10 However, this is not enough for pediatric tumors. In our pe- diatric patient’s tumors, although atypical mitosis was observed, the case was accepted as ACA be- cause there was no other Wienecke criteria. This patient has been disease free for 48 months. In the literature, pediatric oncocytic adrenocortical tu- mors are extremely rare.14,15 We think that the pe- diatric cases in our series can contribute to the lit- erature in terms of pathological features, especially those of oncocytic cells.
At the present time, we know that adrenocorti- cal tumors have different biological behaviors de- pending on the age groups and the cell character- istics.5,6,9,14,16
Oncocytic adrenal tumors differ from their nononcocytic counterparts in some respects. Ac- cording to Weiss criteria, a tumor is defined as ad- renocortical carcinoma when it has three or more of the criteria in Table 1. However, all OACTs have at least three criteria such as eosinophilic cytoplasm, nuclear atypia, and diffuse growth. Therefore, OACTs could be easily overdiagnosed as carci-
nomas. Bisceglia et al.6 proposed major (i.e., high mitotic rate, atypical mitoses and venous invasion) and minor (i.e., large size and huge weight, ne- crosis, capsular invasion and sinusoidal invasion) criteria for distinguishing malignancy in oncocytic tumors. According to Lin-Weiss-Bisceglia scoring system, the presence of one major criterion is suf- ficient for malignancy (ACC), whereas presence of any minor criteria is necessary for uncertain malig- nant potential (borderline ACT). If there are no mi- nor and major criteria, the mass can be considered benign (ACA). In the present study, of the 16 cases, 12 were diagnosed as benign (ACA), 1 as uncer- tain malignant potential (borderline ACT), and 3 as malignant (ACC) based on these criteria. If Weiss criteria were used, all cases would be considered malignant. Considering the follow-up information from our patients, at least 10 adult and 2 pediatric patients would have been overdiagnosed. The re- sults of our study support the importance of using Bisceglia criteria in adult OACTs. Therefore, for pediatric patients, the Lin-Weiss-Bisceglia scoring system may lead to misdiagnosis because high mi- totic count, atypical mitosis, and venous invasion can be seen in pediatric adrenocortical tumors, as in our case. Importantly, these criteria alone are not sufficient.
The other important issue is the accurate diag- nosis of OACTs. For the diagnosis of these tumors, at least one minor Lin-Weiss-Bisceglia criterion without major criterion is essential. If the tumor is larger than 10 cm in diameter, this is considered as minor criterion, according to Lin-Weiss-Bisceg- lia.6 However, Mearini et al.7 recommend resection for all adrenal masses over 6 cm. In a study involv- ing 887 patients, a diameter greater than 4 cm was shown to have high sensitivity but low specificity for the detection of adrenocortical carcinoma; only 24% of the lesions were malignant.17 However, this finding may differ for adrenal oncocytic neoplasms because most oncocytic adrenal tumors display a large volume even though they exhibit benign be- havior.18
In the present study, borderline OACT, 41.66% of ACAs and 33.33% of ACC were ≥ 6 cm in di- ameter. Moreover, none of the tumors was ≥ 10
cm, except one borderline OACT. We did not find any relationship between large tumor size and ma- lignancy.
In the present study, borderline OACT con- tained only one minor criterion, namely large size. None of the other features regarding malignancy was seen. Unfortunately, we did not obtain the sur- vival information for borderline OACT. Therefore, the behavior of borderline OACTs remains a mys- tery.
In conclusion, determining the clinical, his- tological, and molecular characteristics of these extremely rare tumors can provide us with impor- tant information for early diagnosis, treatment, and follow-up. To achieved optimal patient man- agement, there is a need for research involving molecular techniques applied to these tumors in larger series.
REFERENCES
1. Chang A, Harawi SJ. Oncocytes, oncocytosis and onco- cytic tumours. Pathol Annu. 1992,27:263-304.
2. Tallini G. Oncocytic tumours. Virchows Arch. 1998;433: 5-12.
3. Baloch ZW, LiVolsi VA. Oncocytic lesions of the neuro- endocrine system. Semin Diagn Pathol. 1999,16:190-9.
4. Kakimoto S, Yushita Y, Sanefuji T, Kondo A, Fujishima N, Kishikawa M, Matsumoto K. Non-hormonal adre- nocortical adenoma with oncocytoma-like appearances. Hinyokika Kiyo. 1986;32:757-63.
5. Hoang MP, Ayala AG, Albores-Saavedra J. Oncocytic adrenocortical carcinoma: a morphologic, immunohis- tochemical and ultrastructural study of four cases. Mod Pathol. 2002;15:973-8.
6. Bisceglia M, Ludovico O, Di Mattia A, Ben-Dor D, Sandbank J, Pasquinelli G, Lau SK, Weiss LM. Adreno- cortical oncocytic tumors: report of 10 cases and review of the literature. Int J Surg Pathol. 2004;12:231-43.
7. Mearini L, Del Sordo R, Costantini E, Nunzi E, Porena M. Adrenal oncocytic neoplasm: a systematic review. Urol Int. 2013;91:125-33.
8. Wong DD, Spagnolo DV, Bisceglia M, Havlat M, Mc- Callum D, Platten MA. Oncocytic adrenocortical neo- plasm-a clinicopathologic study of 13 new cases empha- sizing the importance of their recognition. Hum Pathol. 2011;42:489-99.
9. Weiss LM, Medeiros LJ, Vickery AL Jr. Pathologic fea- tures of prognostic significance in adrenocortical carci- noma. Am J Surg Pathol. 1989;13:202-206.
10. Wieneke JA, Thompson LD, Heffess CS. Adrenal corti-
cal neoplasms in the pediatric population: a clinicopatho- logic and immunophenotypic analysis of 83 patients. Am J Surg Pathol. 2003;27:867-81.
11. Lloyd RV, Tischler AS, Kimura N, McNicol AM, Young WF Jr. Tumors of the adrenal gland. In: World Health Or- ganization Classificationof Tumors of Endocrine Organs. RA DeLellis, RV Lloyd, PU Heitz, C Eng, eds. Lyon, France: IARC Press; 2004. Pp. 135-46.
12. Steward M. The adrenal cortex. In: Williams Textbook of Endocrinology, 10th ed. Larsen PR, Kronenberg HM, Melmed S, Polonsky KS, eds. Philadelphia, PA: Saun- ders; 2002.
13. Blanes A, Diaz-Cano SJ. Histologic criteria for adreno- cortical proliferative lesions: value of mitotic figure vari- ability. Am J Clin Pathol. 2007;127:398-408.
14. Blanes A, Diaz-Cano SJ. DNA and kinetic heterogeneity during the clonal evolution of adrenocortical prolifera- tive lesions. Hum Pathol. 2006;37:1295-303.
15. Spano D, Heck C, De Antonellis P, Christofori G, Zollo M. Molecular networks that regulate cancer metastasis. Semin Cancer Biol. 2012;22:234-49.
16. Tiwari N, Gheldof A, Tatari M, Christofori G. EMT as the ultimate survival mechanism of cancer cells. Semin
Cancer Biol. 2012;22:194-207.
17. Terzolo M, Boccuzzi A, Bovio S, Cappia S, De Giuli P, Alì A, Paccotti P, Porpiglia F, Fontana D, Angeli A. Immunohistochemical assessment of Ki-67 in the dif- ferential diagnosis of adrenocortical tumors. Urology. 2001;57:176-82.
18. Ranganathan S, Lynshue K, Hunt JL, Kane T, Jaffe R. Unusual adrenal cortical tumor of unknown biologic potential: a nodule in a nodule in a nodule. Pediatr Dev Pathol. 2005;8:483-8.
19. Agarwal S, Agarwal K. Rare pediatric adrenocortical carcinoma with oncocytic change: a cytologic dilemma. Endocr Pathol. 2011;22:40-3.
20. ). Ru W, Yang M, Xu S, Li M, Tang D. Management and prognosis of adrenocortical tumors in children: can we find out an appropriate points-scoring system to predict prognosis? Pediatr Surg Int. 2017;33:705-11.
21. Angeli A, Osella G, Ali A, Terzolo M. Adrenal inciden- taloma: an overview of clinical and epidemiological data from the National Italian Study Group. Horm Res. 1997;47:279-83.
22. Reyna-Villasmil E, Santos-Bolívar J, Prieto-Montaño J. Adrenal oncocytoma. Cir Esp. 2011;89:692-3.