Genomic Sequencing in Oncocytic Adrenal Carcinoma May Provide Insights into Disease Progression and Treatment Options

Oncocytic adrenal carcinoma (OAC) is a rare histologic subtype of adrenal cortical carcinoma (ACC) characterized by >90% oncocytic cells. Unlike ACC, OACs have a reduced incidence of adrenal hormone production, larger size, and longer time to recurrence (17.5 months vs 8 months). Genetic mutations in CTNNB1 are associated with decreased survival in ACC but their role in OAC is unknown. Here, we present a case of OAC highlighting the importance of comprehensive genomic profiling in predicting time to recurrence. A 72-year-old woman presented with rapidly progressive muscle weakness, new-onset type 2 diabetes mellitus, resistant hypertension associated with hypokalemia, and profound cognitive decline. Hormonal evaluation was consistent with ACTH-independent Cushing syndrome. A computed tomography scan of the abdomen showed a 7.1-cm heterogenous left adrenal mass. Pathology confirmed OAC after an en bloc left adrenalectomy. Next-generation sequencing revealed somatic mutations in CTNNB1, CDKN2A, and CDKN2B. Disease progression at 5 months after left adrenalectomy was comparable to other histopathological types of ACC, emphasizing the impact of genomic alterations in OAC.