SUN-491 - Adrenocortical Carcinoma Metastasis to the Thyroid: A Case Study

Adrenocortical carcinoma (ACC) is rare aggressive malignancy with an annual US incidence of about 1-2 cases per million people, and a bimodal age distribution. ACC carries a poor prognosis and unfortunately, about 70% of patients are found to be at a stage III or IV at the time of diagnosis. ACC commonly spreads to the liver, lungs, lymph nodes, peritoneum and less frequently, bone. Through literature review, there have been a few case reports presenting unusual incidents of metastasis to the leptomeninges or the brain as well as gastric, pancreatic, or delayed cutaneous metastases. However, although thyroid cancers such as follicular thyroid carcinomas have been observed to spread to the adrenal glands, there is limited data of ACC metastasizing to the thyroid. We present a rare case of a middle-aged woman with progressive ACC including thyroid metastasis.

Case presentation:
52-year-old female diagnosed with ACC after six months of evolving left flank and abdominal pain. Computed tomography (CT) revealed a 2.7 cm x 10.9 cm x 12.2 cm heterogeneous left adrenal gland tumor with mass effect upon the adjacent retroperitoneal structures and spleen. She underwent a left adrenalectomy with negative surgical resection margins and pathology confirming ACC confined to the adrenal cortex without invasion into the adrenal capsule. Restaging imaging including CT thorax and abdomen/pelvis and positron emission tomography (PET) scans revealed a pulmonary nodule in the right lower lung lobe and abnormal uptake in the anterior left lobe of the liver. Biopsies of the liver and pulmonary lesions confirmed ACC metastases. She was treated with doxorubicin, etoposide, cisplatin, and mitotane however disease progressed despite reaching mitotane therapeutic levels. Subsequently, CT scan showed a new 3.5 x 2.5 cm hypodense nodule in the right thyroid lobe with follow up PET scan revealing interval increased activity in this same area. Right thyroid fine needle aspiration (FNA) reported malignant carcinoma with severe nuclear pleomorphism, morphologically compatible known ACC. Pembrolizumab was initiated but halted due to adverse events; thereafter transitioned to a clinical trial until disease progression. Currently she is on off-label cabozantinib.

Conclusion:
ACC is an uncommon malignancy with a poor prognosis. Our case presents a rare metastasis of ACC to the thyroid with disease progression despite adrenalectomy and multiple systemic therapy lines.

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