Adrenal metastases from lung cancer are a common occurrence. During the course of primary lung cancer, the presence of adrenal metastases can have significant prognostic implications, because surgical resection of solitary metastases from operable lung cancer might be expected to improve survival
7. Any adrenal mass found on a preoperative CT scan in a patient with lung cancer should be biopsied to exclude a benign tumor. If an adrenal metastasis is found and if the lung lesion is curable (stage I or stage II), resection of the adrenal lesion is prudent. Thus, it is very important to distinguish between a benign and a malignant lesion in patients with a known malignancy, particularly lung cancer
8,9.
In this report, a 59-year-old woman was initially thought to be a case of primary lung cancer with presumptive solitary adrenal metastasis, suggesting M1b disease. Since most solitary adrenal masses are non-malignant even in patients with known lung cancer
1,3,8, we thought it may be another type of adrenal disease, such as an adenoma or a functional endocrine tumor. As she had never experienced any episodes associated with catecholamine excess, we tried to perform aspiration cytology on the adrenal lesion, but the sample was unsatisfactory to make a definitive diagnosis. We did not perform further aspiration because of the possibility of significant morbidity and other complications, such as pneumothorax, infection, and hemorrhage, that have been reported in 8-13% of these patients
10. Adrenal biopsy is often performed to rule out metastatic disease of the gland, but can be life-threatening as it can evoke an adrenergic storm in the case of pheochromocytoma
11. Although we did not know the exact pathology of the adrenal lesion, we decided to surgically remove the lung and adrenal mass, because surgical delay in lung cancer could influence prognosis. Unfortunately, there are currently no confirmatory diagnostic modalities to distinguish benign from malignant adrenal masses. Burt et al.
1 reported that the specificity of MRI in predicting a metastatic lesion was 24%, and the false-positive was 67%. More recently, Schwartz et al.
9 found that in cases with lung cancer and synchronous adrenal masses, a chemical shift MRI technique showed 96% sensitivity and 100% specificity in diagnosing adrenal adenomas; therefore, it could obviate the need for needle biopsy in 55% of the cases. These data suggest that for evaluating adrenal masses, MRI may be helpful in diagnosing benign rather than malignant lesions. Metser et al.
5 showed that a cutoff standardized uptake value (SUV) of 3.1 for
18F-FDG PET-CT resulted in a sensitivity of 98.5% and specificity of 92% in differentiating all adenomas from malignant lesions. The PET-CT of this patient showed increased uptake of
18F-FDG (SUV, 3.5) in the adrenal mass. Increased
18F-FDG uptake has been seen in pheochromocytoma and some adenomas, though the reason for it is not fully understood. It is suggested that the functional status of the lesions may affect the intensity of uptake, with an increased
18F-FDG uptake in functional adrenal masses
12. Thus, we performed right adrenalectomy prior to right upper lobectomy.
In cases of lung cancer with a synchronous adrenal mass, the adrenal lesion could be an adenoma, metastasis, pheochromocytoma, paraganglioma, or another type of endocrine tumor. Very rarely, it could be a pheochromocytoma infiltrated with metastatic lung cancer cells
13. Moreover, pheochromocytoma is a rare catecholamine-secreting neuroendocrine neoplasm originating from the chromaffin cells of the adrenal medulla with an annual incidence of about 2-8 per million people
14. It is important to exclude synchronous functional adrenal tumors prior to adrenalectomy because of the rare possibility of simultaneous lung cancer and pheochromocytoma
15. Biochemical testing before the biopsy of adrenal masses is also critical to exclude a catecholamine-secreting tumor because of serious potential operative complications. As the biochemical tests were within the normal ranges before surgery, the adrenal lesion of this patient is possibly a silent- or an early-stage pheochromocytoma. Additionally, her hypertension did not return to normal after the operation, and therefore, was not considered to be associated with the pheochromocytoma. She continues to be in good health, 2 years after the operations.
In conclusion, we report the successful treatment of a 59-year-old woman with a rare synchronous presentation of an early-stage non-small cell lung carcinoma and a right silent pheochromocytoma. In our opinion, the surgeries for both lung cancer and pheochromocytoma significantly improved her prognosis. This case illustrates that all synchronous adrenal masses that are displayed incidentally in cases of primary lung cancer should be investigated.