1. FDG PET/CT Characteristics of Adrenal Benign and Malignant Lesions
Nicholas Plaxton, Raghuveer Halkar, MD 1,
Bruce Barron, MD 1, MD 1,2
1Emory University School of Medicine, 2 Atlanta Veterans Affairs Medical Center
LEARNING ADRENAL ANATOMY PHEOCHROMOCYTOMA METASTATIC
OBJECTIVES • Uncommon neoplasm that release • Lung, breast, renal, ovary, lymphoma, leukemia
catecholamine and melanoma cancers are most common to
• 85% of arise from adrenal medulla metastasize to adrenals.
1. Pictorial review of clinical
• 0.1 – 0.3% hypertension caused by • 50% adrenal lesions in cancer patients are benign
features of major adrenal
pheochromocytomas • CT characteristics are highly variable
benign and malignant lesions
• 90% occur sporadic, 10% endocrine syndromes
characteristics in FDG LUNG
• FDG activity and Hounsfield variable
PET/CT. Adrenal metastasis occur 1.3% in lung cancer.
2. Tabular review of general
guidelines for adrenal lesions
to assist benign versus
malignant determination.
Liver Stomach
Aorta Pancreas
IFC Left adrenal
INTRODUCTION Right adrenal Spleen
Left kidney
Bilateral adrenal metastases
MIBG scan Adrenal pheochromocytoma
BREAST
Between 2 – 7% of patients have
LEIOMYOSARCOMA
CT Cross-section at level of adrenal glands Metastasize to the lungs, liver, bones and brain,
incidental adrenal masses on but rarely to the adrenal glands.
imaging studies in the general
• Very rare malignant cancer of smooth muscle
population. Most of these
incidental adrenal lesions are ADRENAL ADENOMA • High SUV and Hounsfield not characteristic
benign non-hyper functioning • Focal enlargement in the adrenal gland
adenomas that require no • Contain varying degrees of adipose tissue
treatment. On FDG PET/CT the • Low or negative Hounsfield units ( -20 to 30)
incidence of malignant adrenal • FDG activity below liver
lesions increases due to common
metastatic spread in lung cancer,
breast cancer, renal cell Bilateral adrenal metastases
carcinoma, neuroendocrine
RENAL
tumors and melanoma.
0.03% incidence and adrenal gland metastasis is
Determining if adrenal lesions are Adrenal adenoma with 0 Hounsfield, SUV below liver
typical site. Renal cancer SUV is variable.
benign or malignant can be Right adrenal leiomyosarcoma wrapping
around the IVC with 6.2 SUV, size 6 cm
paramount in directing cancer
treatment to be curative or ADRENAL CYST
palliative. We selected FDG
• Very rare 0.01% incidence HIT SYNDROME
PET/CT cases with strong key
• Types (endothelial, epithelial, pseudocyst, parasitic) • Heparin Induced Thrombocytopenia is rare
representative findings to help
• 40% cysts are pseudocyst can become malignant • Can cause bilateral adrenal hemorrhage and
illustrate benign and malignant
• Hounsfield for fluid (0 – 15), no FDG activity insufficiency
adrenal lesions. Tabular review of
PET SUV values, Hounsfield • Hematoma/hemorrhage Hounsfield (50 – 90)
units and lesion size in the
different cases will be discussed.
Right adrenal metastasis s/p nephrectomy
Adrenal fluid filled cyst with 15 Hounsfield and no FDG activity
GENERAL GUIDELINES
ADRENAL HYPERPLASIA Benign Indeterminate Malignant
• Homogeneous diffusely enlarged glands HIT with bilateral adrenal hemorrhage and intense SUV Size < 3 cm 3 cm < & < 6 cm > 6 cm
• SUV equal to or slightly higher than liver SUV Hounsfield < 0 >0 variable
• Hounsfield units similar to a normal adrenal gland
MYELOLIPOMA SUV Less liver Equal liver Greater liver
• Benign tumor composed of mature adipose Shape Round Irregular
Smooth Heterogeneous
tissue and hematopoietic elements
Uniform Poorly defined
• Hounsfield units ( -30 to -100)
• Incidence 0.1%, 3% of all adrenal tumors
CONTACT Bilateral adrenal hyperplasia 8 Hounsfield, SUV 2.0 (liver SUV 2.9)
CONCLUSION
Nicholas A. Plaxton M.D. LYMPHOMA Adrenal lesions on imaging studies are common
in the general public and this incidence
Depart of Radiology and • Primary adrenal lymphoma is extremely rare increases in PET/CT images secondary to the
Imaging Sciences • Lymphoma involvement in adrenal glands is oncologic patient population and frequent
Division of Nuclear Medicine more common than primary adrenal lymphoma adrenal metastases in many cancers. Having a
Email: nickplaxton@emory.edu • Intense FDG activity with high SUV strong knowledge of the different characteristics
Phone: 404 712 4868 • Hounsfield units are not characteristic of adrenal lesions on PET/CT such as sizes,
Left adrenal myelolipoma Hounsfield units and SUVs, can assist in
determining benign versus malignant lesions and
ADRENAL LIPOMA guide the course of treatment. However, many
CT characteristics of malignant adrenal lesions
• Composed of adipose tissue ( HU -50 to -100)
are variable and the advent of PET/MR imaging
• Usually has no significant FDG activity
may better characterize adrenal lesions. The
Thanks to Eric Jablonowski for take home caveat is that adrenal lesion
illustration and Dr. David Brandon guidelines are not hardened rules and close
for review. follow up imaging or tissue sampling should be
incorporated if suspicion remains.
Poster Design & Printing by Genigraphics® - Primary adrenal lymphoma A 5 cm adrenal lipoma with - 62 Hounsfield and no FDG activity
800.790.4001 References available upon request.