Clinicopathological description of 43 oncocytic adrenocortical tumors: importance of Ki-67 in histoprognostic evaluation

Abstract

Oncocytic adrenocortical tumors are a rare subtype of adrenal tumors with challenging diagnosis and histoprognostic assessment. It is usually believed that oncocytic adrenocortical tumors have a more indolent clinical behavior than conventional adrenocortical tumors. As the Weiss score overestimates the malignancy of oncocytic adrenocortical tumors owing to intrinsic parameters, alternative scores have been proposed. The Lin-Weiss-Bisceglia score is currently recommended. We performed a large nationwide multicenter retrospective clinicopathologic study of oncocytic adrenocortical tumors. Among the 43 patients in our cohort, 40 patients were alive without disease, 2 patients died of their disease and 1 patient was alive with relapse after a median follow-up of 38 months (20-59). Our data revealed that over 50% of the oncocytic adrenocortical tumor cases were diagnosed as carcinoma whatever the classification systems used, including the Lin-Weiss-Bisceglia score. The exception is the Helsinki score, which incorporates the Ki-67 proliferation index and was the most specific prognostic score for oncocytic adrenocortical tumor malignancy without showing a loss in sensitivity. A comparison of malignant oncocytic adrenocortical tumors with conventional adrenocortical carcinomas matched for age, sex, ENS@T stage and surgical resection status showed significant better overall survival of malignant oncocytic adrenocortical tumors.

Treatment and management of adrenal cancer in a specialized Australian endocrine surgical unit: approaches, outcomes and lessons learnt

“…One interesting subset includes five patients with oncocytic tumours. Oncocytic tumours, where at least 50% of the tumours comprise oncocytic cells, have been described as having more indolent courses compared to conventional ACC, with improved survival . This was confirmed in our cohort where Stage 2 oncocytic ACCs had equivalent survival to high Ki‐67 non‐oncocytic Stage 1 ACC.…”

A case of adrenocortical oncocytic carcinoma arising in ectopic adrenal tissue: a multidisciplinary diagnostic challenge

“…However, it should be emphasised that the determination of the oncocytic character of the tumour cells represents another diagnostic hurdle. One of the reasons for this is that the determination of oncocytic character is based on subjective morphological criteria [2]. Our case was no exception, thereby requiring consultation with various pathologists.…”

“…Our case was no exception, thereby requiring consultation with various pathologists. Such diagnostic subjectivity is a major limitation to the use of a histoprognostic score [2]. Currently, AONs are classified based on the modified Weiss criteria, also known as the Lin-Weiss-Bisceglia (LWB) system, to elucidate their malignant potential [8], as this score does not include relatively more subjective histologic criteria, as in the original Weiss score [2].…”

“…Adrenocortical carcinoma is a rare, typically aggressive cancer with an incidence of 0.7 per 2 million cases annually [1]. Adrenocortical oncocytic neoplasm (AON) is a rare and diagnostically challenging subtype of adrenocortical tumours [2]. Most AONs are nonfunctional and, therefore, are discovered incidentally or present with vague abdominal or back pain.…”

A rare case of oncocytic adrenocortical carcinoma clinically presented as an incidentaloma

“…In our present case, identification of 7 mitoses/50 HPFs and atypical mitoses definitively led to the diagnosis of oncocytic ACC. Renaudin et al reported 43 patients with oncocytic adrenocortical tumors in France and showed that both the Weiss criteria and the LWB criteria seemed to overestimate the potential malignancy of these tumors [16]. Further studies would be necessary to characterize the malignant potential of oncocytic tumors more accurately.…”