Myxoid and Sarcomatoid Variants of Adrenocortical Carcinoma: Analysis of Rare Variants in Single Tertiary Care Center

Abstract

The aim of this study is to describe rare variants of adrenocortical carcinoma (ACC) and to compare the prognosis with that of conventional ACC. We retrospectively reviewed 8 cases of myxoid variant, 1 sarcomatoid variant, and 14 cases of conventional ACC, who underwent surgical resection at the Asan Medical Center between 1996 and 2014. An analysis of the clinicopathological characteristics, including the Weiss score, Ki-67 labeling index, and reticulin framework assessment is presented. The mean age of patients with myxoid/sarcomatoid ACC was 45 years; 4 out of 9 patients were women. Mean primary tumor size was 12.9 cm and the mean weight was 702.4 g. Seven patients presented in an advanced stage (stage III/IV); 8 of these eventually developed distant metastasis. The mean Weiss score was 5.0 points and the Ki-67 labeling index was 15.6%. The extent of myxoid or sarcomatoid change on histological examination ranged from 10% to 75% of the examined tumor areas; reticulin framework alteration was observed in all cases. Four patients showed venous tumor thrombus. Most of the clinicopathological parameters were not significantly different from those of conventional ACC. However, myxoid or sarcomatoid variant (hazard ratios [HR], 3.59; 95% confidence intervals [CI], 1.13–11.38; P = 0.030) and Ki-67 labeling index (HR, 3.97; 95% CI, 1.18–13.41; P = 0.030) were independent predictors of overall survival after adjusting for age and sex. Myxoid or sarcomatoid histological features or an increased Ki-67 labeling index may be associated with poor overall survival in patients with ACC.

Adrenocortical Carcinoma: Updates of Clinical and Pathological Features after Renewed World Health Organisation Classification and Pathology Staging

“…Myxoid ACC is an uncommon variant of ACC and first reported by Tang and colleagues in 1979 in a 41-year-old woman [ 140 ]. Up to the year 2020, 47 cases of myxoid ACC have been reported in the literature [ 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 , 154 ].…”

“…Lipometaplasia were reported in 21% ( n = 5) of myxoid ACC [ 143 , 149 , 150 , 152 ]. The morphology is a reactive degenerative or metaplastic process in tumour cells which appears to be detected in myxoid ACC.…”

A novel case of myxoid variant of adrenocortical carcinoma in a patient with multiple endocrine neoplasia type 1

“…These features could result in the difficulty of differential diagnosis, especially from metastatic adenocarcinoma to the adrenal gland [8,[20][21][22]. The majority of previously reported cases of myxoid ACC had clinical characteristics similar to those of conventional ACC, but Sung et al indicated that the presence of myxoid histological features in ACC was indeed associated with more aggressive clinical behavior and poorer overall survival than conventional ACC [9], which may explain the relatively aggressive biological course of our patient.…”

“…The myxoid variant of ACC was first reported in 1979 [19], and approximately 50 cases have been reported to date in the English-language literature to the best of our knowledge [9]. In the year 2017 World Health Organization classification, myxoid ACC was firstly recognized as the distinctive subtype of ACC [20].…”

“…Among those subtypes, myxoid variant of ACC was recently identified and characterized by tumor cells arranged in cords, clusters, or pseudoglandular structures that are embedded in a prominent myxoid stromal background. Myxoid ACC is also considered to harbor more aggressive clinical course than non-myxoid ACC [8,9].…”