HEALTH & HUMAN SERVICES - USA VIREMENT OF
HHS Public Access Author manuscript JAMA. Author manuscript; available in PMC 2020 August 20.
Published in final edited form as: JAMA. 2017 July 04; 318(1): 84-85. doi:10.1001/jama.2017.6326.
A Large Adrenal Tumor With Marked 18F-Fluorodeoxyglucose Uptake
David Taïeb, MD, PhD,
Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Aix-Marseille University, Marseille, France;
Frédéric Sebag, MD,
Department of Endocrine Surgery, Conception University Hospital, Aix-Marseille University, Marseille, France;
Karel Pacak, MD, PhD, DSc
Eunice Kennedy Shriver National Institute of Child Health & Human Development, Section on Medical Neuroendocrinology, National Institutes of Health, Bethesda, Maryland.
A 56-year-old woman was referred for evaluation of an incidentally discovered adrenal mass. She experienced no symptoms of weight loss, headache, sweating, palpitations, pallor, anxiety, menstrual abnormalities, or mood changes; had no known history of cancer or hypertension; and was not taking any medications. On physical examination, her blood pressure was 135/73 mm Hg, and her heart rate was 82/min. There was no truncal or facial obesity, acne, striae, hirsutism, or proximal muscle weakness. Laboratory analysis showed normal blood cell counts and levels of electrolytes, liver enzymes, and lactate dehydrogenase. Further biochemical evaluation revealed normal levels of plasma and urinary cortisol, serum aldosterone and 17-hydroxyprogesterone, and urinary metanephrines. A computed tomography (CT) scan revealed a 5.5 × 4.3-cm left adrenal tumor with heterogeneous appearance, a hypodense central area, and irregular margins, with a density of 36 Hounsfield units (HU). Relative and absolute adrenal washout values (a measure of the disappearance of contrast media from a mass after 10 minutes) were 23% and 47%, respectively. A positron emission tomography (PET)/CT scan using 18F-fluorodeoxyglucose (18F-FDG) was performed for further tumor characterization (Figure).
What to Do Next
C. Request a surgical consult for adrenalectomy
Corresponding Author: Karel Pacak, MD, PhD, DSc, Eunice Kennedy Shriver National Institute of Child Health & Human Development, Section on Medical Neuroendocrinology, National Institutes of Health, 10 Center Dr, MSC-1109, Bldg 10, CRC, Room 1E-3140, Bethesda, MD 20892-1109 (karel@mail.nih.gov).
Additional Contributions: We thank the patient for providing permission to share her information. Additionally, we would like to thank Katherine I. Wolf for her editorial assistance with this article.
Diagnosis Adrenocortical carcinoma
Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
The key to the correct diagnosis was the presence of a nonsecreting, large heterogeneous adrenal mass with a high density on CT and marked 18F-FDG uptake on PET imaging. A high tumor density on precontrast CT, along with low relative and absolute washout values, further contributed to the diagnosis of adrenocortical carcinoma.1 Surgery and subsequent histopathological examination was the next step for a definitive diagnosis.
Discussion
Adrenal incidentalomas are discovered on approximately 3% to 4% of abdominal CT scans.2 While most lesions are adrenocortical adenomas, other adrenal masses include pheochromocytoma, adrenocortical carcinoma, lymphoma, myelolipoma, cyst, hematoma, nodular hyperplasia, ganglioneuroma, schwannoma, oncocytoma, and metastatic lesions.
Adrenal incidentalomas with unenhanced densities less than 10 HU on CT, or with relative and absolute washout threshold values of 40% or greater and 60% or greater, respectively, are presumed to be adenomas. In this scenario, for tumors smaller than 4 cm, further imaging should not be performed. However, in patients with a mass 4 cm or larger, follow- up imaging should be performed after 6 to 12 months.1 Tumor size is a useful predictor of malignancy in incidentalomas, with likelihood ratios of 10%, 19%, and 47% for cancer in adrenocortical tumors 4 cm or larger, 6 cm or larger, and 8 cm or larger, respectively.3 Irregular tumor margins, density greater than 20 HU, intratumoral necrosis or hemorrhage, heterogeneous enhancement, invasion into the adjacent structures, and surrounding venous invasion are other features that increase the suspicion of adrenocortical carcinoma. In adrenal masses with unenhanced densities of 10 HU or greater and insufficient washout values on CT, as in this case, a PET/CT scan using 18F-FDG can further characterize the mass and provide a metabolic ratio of the maximal standardized uptake value (SUVmax) of the tumor to the liver.4 An uptake ratio (SUVmaxtumor:SUV maxliver) greater than 1.5 is useful for differentiating malignant from other adrenal masses (negative predictive value, 96.9%; positive predictive value, 56.5%).5,6 Other studies have shown that an uptake ratio less than 1 can rule out an adrenocortical carcinoma. In this case, the uptake ratio was 18.
An adrenal biopsy can be performed to exclude a unilateral metastatic deposit in the presence of a primary tumor or when a primary adrenal lymphoma is suspected, but only after pheochromocytoma is excluded. In patients at risk for lung cancer with an unknown primary tumor, a fine-cut chest CT could be considered to exclude a small primary lung carcinoma missed by PET/CT scan using 18F-FDG. Given the low suspicion for metastatic disease (negative history of cancer and no primary lesion on imaging) and lymphoma (absence of systemic symptoms, normal levels of lactate dehydrogenase, infiltrative appearance, and nodal or contralateral adrenal involvement), a biopsy would not be an appropriate next step in this case.7 Adrenal magnetic resonance imaging could not definitively diagnose adrenocortical carcinoma; therefore, it would not be appropriate in this case.
With an incidence of 0.5 per million per year to 2 per million per year, adrenocortical carcinoma is rare. Its clinical features often reflect steroid oversecretion, causing Cushing syndrome orvirilization, rapid tumor growth with mass effect (abdominal pain), and spread
to surrounding or distant tissues. Treatment for adrenocortical carcinoma includes a laparoscopic or open radical adrenalectomy with removal of the adrenal gland, periadrenal adipose tissue, and locoregional lymph nodes. After surgery, adjuvant mitotane therapy may be given. Treatment of metastatic disease is limited to palliative debulking surgery, adjuvant mitotane treatment, systemic chemotherapy, and/or radiation therapy.8 The 5-year overall survival ranges from 15% to 84%.9,10
Patient Outcome
The patient underwent a laparoscopic radical adrenalectomy. Final histopathological analysis confirmed the diagnosis with a Weiss score of 6, a Ki-67 value of 10%, and a component of large cells with abundant eosinophilic and granular cytoplasm (Hürthle or oncocytic cells), which could explain the extremely high 18F-FDG uptake by the tumor. Subsequently, the patient was treated with adjuvant mitotane. Relapse was not noted at 5- year follow-up.
REFERENCES
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| WHAT WOULD YOU DO NEXT? | |
|---|---|
| A. | Perform a biopsy of the mass |
| B. | Order a repeat CT scan in 3-6 months |
| C. | Request a surgical consult for adrenalectomy |
| D. | Perform adrenal magnetic resonance imaging |