Synchronous Occurrence of Ipsilateral Adrenocortical Carcinoma and Renal Cell Carcinoma: A Rare Case Report

Introduction:
Adrenocortical carcinoma (ACC) is a rare malignancy with a reported incidence of 0.5 - 2 cases per million per year. Because of close proximity of adrenal glands and kidneys, ACC may often metastasize to the adjacent renal parenchyma. However, synchronous occurrence of ACC and renal cell carcinoma (RCC) are very rare with only two previously reported cases.

Case Description:
A 51-year-old man with medical history of Type 2 diabetes, obesity, hypertension, hyperlipidemia, and anxiety was referred to clinic after he was incidentally noted to have left adrenal mass on a computerized tomography (CT) scan of chest. His CT scan was performed for evaluation of an asymptomatic incidentally noted lung nodule noted on a chest x-ray. His subsequent MRI of abdomen showed a right adrenal mass measuring 2.7 x 2.7 cm and a right renal mass measuring 3.1 x 2.9 cm. Physical examination revealed clinically normal cardiorespiratory and abdominal systems. He did not have any palpable lymph nodes in the neck, axilla or inguinal area. Laboratory testing showed normal complete blood count and normal biochemistry. Subsequent testing for plasma metanephrines, urinary metanephrines, aldosterone, renin activity and AM cortisol levels revealed normal levels.

He then underwent robot-assisted right adrenalectomy and right partial nephrectomy. The renal mass showed features of clear cell carcinoma which was well encapsulated. The adrenal mass was well demarcated, but there were areas suspicious for invasion into adjacent adrenal tissue. Immunostains showed a number of Melan A and synaptophysin positive tumor cells, while inhibin and calretinin stain was positive only in a few tumor cells. Stains for Chromogranin and S-100 were negative. Ki-67 staining showed a relatively low proliferation index of 2% in "hot spots." The case was diagnosed as a low grade adrenal cortical carcinoma based upon Weiss scoring system. Subsequent genetic testing with multi-cancer panel including hereditary paraganglioma/pheochromocytoma panel and renal urinary tract cancer panel (which included 90 genes) were negative. The panel indicated that he had a genetic variant of uncertain significance in the RAD50gene. In the absence of local or distant metastasis, no additional therapy was recommended. Subsequent follow-up CT/MRI chest, abdomen, pelvis performed 5 months later was negative for any local recurrence or metastatic disease.

Discussion:
The diagnosis of adrenal cortical carcinoma (ACC) in our case was based upon the Weiss scoring system (high nuclear grade, atypical mitosis, very low proportion of "clear" cells and suspicion for invasion into adjacent cortex); with each finding assigned a score of 1 and a final score of 4. The low-grade category was based upon the low mitotic rate. Because of higher incidence of RCC compared to ACC, suspicion for a synchronous ACC and RCC is often very low. Hence, careful evaluation in such cases often helps to diagnose synchronous primary tumors which can change the staging and overall management.