Background: Oncocytic adrenocortical carcinoma (ACC) is an uncommon subtype of ACC which may behave more indolently and for which there is limited data regarding efficacy of systemic treatments. Jaw metastases are exceedingly rare in ACC and only one case has been reported in oncocytic ACC.
Case Description: A 65-year-old female had an incidental left abdominal mass on a CTPA scan after presenting with chest pain. CT abdomen scan confirmed a 170x140x110mm arterially-enhancing left adrenal mass with increased avidity on 18F-FDG-PET/CT scan (SUVmax 15.2). Contralateral adrenal was unremarkable. She had no clinical or biochemical evidence to suggest a functional adrenal lesion. Left adrenalectomy in August 2020 confirmed a completely excised 180mm low-grade oncocytic ACC (Ki67 index 10%). Adjuvant systemic therapy was not recommended at multidisciplinary team discussion. In November 2021, she developed left jaw discomfort and numbness and CT scan revealed a 24x13x34mm lytic left mandibular lesion. Biopsy demonstrated metastatic ACC. An 18F-FDG-PET/CT scan showed low-grade uptake in the mandibular lesion (SUVmax 3.4) and a 9mm pulmonary nodule (SUVmax 3.9). She underwent radiation to the left mandible (35Gy/5#) in April 2022. Repeat 18F-FDG-PET/CT scan three-months later demonstrated the left mandibular lesion was no longer FDG-avid however the pulmonary nodule enlarged (11mm) and she received further 48Gy/4# radiotherapy for suspected ACC metastasis. After endocrinology referral, we commenced mitotane 1000mg BD in October 2022 without chemotherapy. She experienced marked liver enzyme derangement within 3-weeks and after initial dose interruption, mitotane was ceased after <1-month exposure. She remains under surveillance and symptomatically well three-years after initial ACC diagnosis.
Conclusions: Mitotane is recommended in advanced, metastatic or recurrent ACC and is often limited by side effects (e.g. hepatotoxicity). Jaw metastasis should be considered in the differential diagnosis for patients with ACC with local symptoms. Radiotherapy can result in symptomatic improvement and metabolic response.