The paradox of size: A case of indolent oncocytic adrenocortical carcinoma and review of literature

Introduction: Oncocytic adrenocortical carcinoma (OAC) is a rare histologic variant of adrenocortical carcinoma. It is characterized by cells with abundant eosinophilic cytoplasm because of high mitochondrial content. Unlike conventional Adrenocortical carcinoma (ACC), which is typically aggressive, OAC often presents with a more indolent biological behavior. The paradoxical features of OAC make the diagnosis and management challenging. Case Report: A 45-year-old female presented with weight loss and left-sided abdominal pain, with initial imaging revealing a large (24 cm) left adrenal mass. Imaging revealed that the mass had radiologic signs and necrotic features concerning for malignancy. She subsequently underwent a left adrenalectomy with en bloc pancreatectomy, splenectomy, and left nephrectomy along with paraaortic lymphadenectomy. Histopathology revealed classic oncocytic morphology with low Ki-67 index (2%) and absence of any lymph node involvement, despite venous and capsular invasion. Due to the venous invasion alone, the tumor met the Lin–Weiss–Bisceglia (LWB) criteria for malignancy. Additional molecular analysis revealed a favorable diagnosis by showing TP53 alterations, low tumor burden, along with microsatellite stability. Postoperatively, the patient recovered and was administered external beam radiation. Conclusion: This case is an example of a rare subtype of ACC and highlights a clinical paradox. In patients with OAC, a large tumor size with necrosis may not always be associated with a poor prognosis. Additionally, OAC has unique diagnostic and management challenges due to its rare nature. However, surgery is still the mainstay treatment for OAC, with the role of mitotane in adjuvant therapy still being explored.