SAT-190 Are Pet Scans Needed in Evaluating Lipid Rich Adrenal Adenomas?

Abstract

Introduction Adrenal glands are highly vascularized organs and can be the foci of metastatic disease. Incidentally discovered adrenal nodules should be evaluated with CT or MRI imaging and biochemical testing. Metastatic lesions do not have a specific clinical presentation or imaging features but are suspected when there is attenuation greater than 10 HU, presence of calcification, hemorrhage, or abnormal enhancement signals in CT scan or MRI. However, malignant lesions can be present along with benign ones as described here. Clinical Case A 74-year-old female initially presented with uncontrolled hypertension in 2002, at which time she was found to have a left adrenal incidentaloma. MRI/MRA of the abdomen with and without gadolinium contrast showed a 2.5 x 2.6 cm left adrenal nodule, described as a benign lipid rich adrenal adenoma. Biochemical testing revealed no evidence of pheochromocytoma, hyperaldosteronism, or hypercortisolism. Follow-up CT scan in 2003 showed the left adrenal nodule was slightly larger (3.0 x 2.5 cm) but remained lipid rich (<10 HU). There was also a new sub-centimeter nodule in the left medial-posterior limb with similar appearance. In the interim, she was diagnosed with a melanoma on her back in 2003, which was resected without any evidence of invasion. In 2004, abdominal MRI with and without gadolinium contrast showed stable left adrenal nodules. As she continued to have persistent hypertension, uncontrolled with several medications, biochemical work-up for pheochromocytoma, hyperaldosteronism, and hypercortisolism was repeated and was again negative. Surveillance CT imaging in 2005 did not show any changes to her adrenal adenomas. In 2016, she presented to the emergency room with a hemorrhagic cerebrovascular accident. MRI of the brain was consistent with metastatic lesions. CT scan of the chest, abdomen and pelvis showed metastatic lesions in the lungs, liver, bone, and spleen. There was a new 8 mm right adrenal nodule noted with no changes in the left adrenal nodules. Biopsy of a subcutaneous chest wall nodule revealed metastatic melanoma. Thus, she was started on palliative immunotherapy with nivolumab. During her follow-up, she had a series of PET CT scans over a 6 month period, which showed increasing size (up to 4.3 cm) and FDG uptake in the left adrenal nodule. Surprisingly, the left adrenal nodule had a predominantly fatty density (mean of 5 HU) but with an area of hyperdensity which could represent either an adenoma with a coexisting metastatic lesion or angiomyolipoma. Biopsy of the left adrenal nodule revealed a metastatic melanoma. Conclusion This case describes a benign adrenal nodule coexistent with a metastatic lesion. As the patient had metastatic melanoma, a PET-CT was ordered. Melanoma is known to metastasize to the adrenal. This case serves to remind clinicians to perform a careful medical history as management and outcomes can be affected.