SHORT TALK ABOUT DIFFERENTIAL DIAGNOSIS ABOUT ADRENAL MASS LESION DDX, COMMON AND LESS COMMON CAUSES WITH CLUES TO DIAGNOSIS AND SOME EXAMPLES HOPPING YOU LIKE IT DR HISHAM ALKHATIB CONSULTANT RADIOLOGIST

1. Adrenal Mass
Hisham AlKhatib, M.D.
Consultant Radiologist

2. •‫اله‬ ‫وعلى‬ ‫هللا‬ ‫رسول‬ ‫على‬ ‫والسالم‬ ‫والصالة‬ ‫هلل‬ ‫الحمد‬
‫اجمعين‬ ‫م‬ّ‫ل‬‫وس‬ ‫وصحبه‬
•، ‫علما‬ ‫وزدني‬ ‫ينفعني‬ ‫بما‬ ‫وعلمني‬ ‫علمتني‬ ‫بما‬ ‫انفعني‬ ‫اللهم‬
‫الحكيم‬ ‫العليم‬ ‫انك‬
• Praise be to Allah and prayers be upon the
Messenger of Allah and his family and
companions.
• Oh God, give me the benefit of what you
have taught me and teach me what benefits
me.

3. ESSENTIAL INFORMATION

4. Key Differential Diagnosis Issues
• Primary diagnostic consideration, particularly
in oncologic population: Differentiate between
adrenal metastasis and incidental adrenal
adenoma
• Imaging intensive approach advocated by
specialty societies to confirm adenomas,
though vast majority of adrenal
incidentalomas are statistically adenomas

5. Key Differential Diagnosis Issues
• Combination of imaging (CT or MR) and
clinical history usually allows confident
diagnosis
• CT and MR protocols geared towards
identifying intracytoplasmic lipid in adenomas
• Lipid-poor adenomas may be problematic,
though washout kinetics, clinical history
• (malignancy), and extraadrenal findings
(additional metastases) aid diagnosis

6. Key Differential Diagnosis Issues
• Cushing syndrome: Excess cortisol; 75-80% due to
pituitary adenoma secreting excess ACTH
• Conn syndrome: Excess aldosterone; 75-80% due to
adrenal adenoma (small)
• Addison syndrome: Adrenal insufficiency; due to
autoimmune disease (80% in Western
• countries), bilateral metastases, adrenal hemorrhage,
or systemic infection
• Clinical history (hypertension) may suggest
pheochromocytoma, but biochemical work-up (urine
metanephrines) confirms diagnosis

7. DIFFERENTIAL DIAGNOSIS

8. Common Diagnosis
• Adrenal Adenoma
• Metastases and Lymphoma, Adrenal
• Adrenal Hemorrhage
• Pheochromocytoma
• Adrenal Cyst
• Retroperitoneal Varices or Vessels (Mimic)

9. Helpful Clues for Common
Diagnoses

10. Adrenal Adenoma
• Well-circumscribed, round or oval,
homogeneous, low-density (0-20 HU) mass on
NECT
– < 10 HU threshold: Highly specific for lipid-rich
adenoma
– Histology of lipid-rich adenomas characterized by
intravoxel signal drop out at outof- phase T1WI

11. Adrenal Adenoma
• Lipid-poor adenomas are best diagnosed on
CT, with unenhanced, enhanced, and 15-
minute delayed imaging to calculate washout
– Absolute washout: > 60%
– Relative washout: > 40%

12. Adrenal Adenoma
• Rare false-positives: hepatocellular carcinoma,
renal cell carcinoma metastases,
pheochromocytoma
– Web-based calculators readily available

18. Metastases and Lymphoma,
Adrenal
• Metastases: Primary sites include lung, breast,
kidney, melanoma
– Cannot always be distinguished from lipid-poor
adenoma by imaging alone
– Clinical history, comparison to prior studies,
identification of additional (extraadrenal) disease
aid diagnosis
– PET/CT very useful in oncology patients; may help
to identify FDG-avid adrenal metastases

19. Metastases and Lymphoma,
Adrenal
• Lymphoma: Non-Hodgkin lymphoma most
common
– Rounded or triangular shape; mild enhancement
– FDG-avid on PET/CT

26. Adrenal Hemorrhage
• Acute: Homogeneous, round, nonenhancing,
hyperdense mass (50-90 HU)
• Chronic: Mass with hypoattenuating center
(pseudocyst), calcification
• Unilateral, usually due to direct trauma or
iatrogenic (e.g., liver transplantation)
• Bilateral usually in response to shock;
postpartum; severe burns, sepsis

29. Pheochromocytoma
• Well circumscribed, round, 3- to 5-cm diameter
(symptomatic lesions)
– Pheochromocytoma that occurs as part of syndrome
may be detected as smaller,
– asymptomatic mass
– Syndromes associated with pheochromocytoma:
Multiple endocrine neoplasia (types II and III);
neurofibromatosis; von Hippel Lindau; Carney
syndrome; tuberous sclerosis

30. Pheochromocytoma
• Hyperintense on T2WI with heterogeneous
bright enhancement
• ± hemorrhage, necrosis, calcification
• Supporting history (e.g., hypertension,
palpitations, headache) and biochemical data
(urine metanephrines) drive diagnosis

36. Adrenal Cyst
• Well-defined, nonenhancing water-density
mass ± calcification (eggshell)
– Thin wall, septa calcification favor cyst rather than
lipid-rich adenoma at NECT
• Rarely large lesion ± internal hemorrhage

39. Retroperitoneal Varices or Vessels
(Mimic)
• Tortuous splenic artery and varices often lie in
suprarenal space
• Contrast-enhanced CT or MR or color Doppler
US can usually establish diagnosis

40. Less Common Diagnosis
• Adrenal Myelolipoma
• Adrenal TB and Fungal Infection
• Adrenal Carcinoma
• Renal Cell Carcinoma (Mimic)
• Gastric Diverticulum (Mimic)
• Adrenal Hyperplasia
• Adrenal Ganglioneuroma

41. Helpful Clues for Less Common
Diagnoses

42. Adrenal Myelolipoma
• Uncommon, nonfunctioning benign tumor
• Macroscopic fat intersperse with soft tissue
(myeloid elements, hemorrhage) at NECT
– Coronal reconstructions may help determine
organ of origin: Adrenal myelolipoma vs. exophytic
renal angiomyelolipoma

43. Adrenal Myelolipoma
• Hyperintense on T1WI, focal areas of signal
loss on fat suppressed techniques
– Interface between fat and soft tissue elements will
lose signal on opposed phase GRE series
• Echogenic mass at ultrasound: May be
indistinguishable from surrounding
retroperitoneal fat unless mass effect

44. Adrenal Myelolipoma
• CT and MR findings are diagnostic in most
cases
– No treatment needed in most cases, though large
myelolipomas may hemorrhage
– Resection advocated for large, asymptomatic, or
atypical lesions

47. Adrenal TB and Fungal Infection
• Heterogeneous, poorly enhancing mass(es)
during acute infection
• Acute: Mild to marked enlargement of adrenal
glands with preserved contour
• Chronic: Small calcified adrenal glands
– Adrenal TB = most common cause of Addison
syndrome (adrenal insufficiency) in 3rd world
countries

49. Adrenal Carcinoma
• Nonfunctioning tumors typically large (> 10
cm) at presentation
• Functioning tumors may be smaller (< 5 cm)
• Early invasion of IVC accounts for poor
prognosis
• ± necrosis, hemorrhage, calcification (30%)

54. Renal Cell Carcinoma (Mimic)
• Large tumor from upper pole of kidney may
simulate adrenal carcinoma
• Look for claw sign (defect in renal cortex at
origin of mass); coronal CT reconstruction or
MR helpful to determine organ of origin

55. Gastric Diverticulum (Mimic)
• Rounded mass in suprarenal site
• May contain fluid, gas, contrast material
• Give extra oral contrast or gas granules; place
patient prone to make diagnosis

56. Adrenal Hyperplasia
• Adrenal glands may appear normal; normal shape
but increased thickness (> 10 mm); or may be
nodular
• Nodular hyperplasia can be difficult to distinguish
from small adrenal adenomas or other lesions (e.g.,
metastases)
• Hyperplasia or swelling may occur in response to
stress, pituitary ACTH-secreting tumor (accounts for
75-80% of Cushing syndrome cases), congenital
adrenal hyperplasia, or ectopic source of ACTH

59. Rare but Important
• Adrenal Collision Tumor
• Adrenal Hemangioma

60. Helpful Clues for Rare Diagnoses

61. Adrenal Collision Tumor
• Coexistence of 2 contiguous but histologically
distinct tumors within same adrenal gland
• Adenoma and myelolipoma; adenoma and
metastases most common combinations

63. Adrenal Hemangioma
• > 10 cm, central low attenuation (necrosis or
fibrosis) ± calcification

64. Alternative Differential
Approaches
• Bilateral adrenal masses: Metastases,
hyperplasia, lymphoma, hemorrhage, TB, or
fungal infection, pheochromocytoma (10%),
adenoma (10%), or combination of 2 types of
masses (e.g., adenoma on 1 side, myelolipoma
on other)

65. THANK YOU