*Chapter 32 - Adrenal Glands and Kidneys (CHERI NOTES) Flashcards
In patients WITHOUT a known malignancy; most small (<4 cm) adrenal nodules are _____________. (p.796)
BENIGN HYPERFUNCTIONING ADRENAL CORTICAL ADENOMAS
Most common adrenal mass found in 4% to 6 % of the population increasing in incidence with age. (p.797)
ADRENAL CORTICAL ADENOMAS
Attenuation of ADENOMAS on unenhanced CT has a range of ____. (p. 797)
RANGE OF -20 TO 30 HU
Benign adenomas are characterized on MDCT by _____. (p. 797)
RAPID WASHOUT OF THE CONTRAST AGENT
Most common primary tumors with adrenal metastases. Name six of them. (p. 797)
- LUNG 2. BREAST 3. MELANOMA 4. GASTROINTESTINAL 5. THYROID 6. ADRENAL
Small adrenal metastases (< __ cm) tend to be homogeneous; well defined and difficult to distinguish from benign; nonfunctioning adenomas (p. 797)
< 4 cm
On CT and MR; larger adrenal metastases (> 4 cm); generally shows features characteristic of malignancy; including _______. Name FIVE of them. (p.797)
- INHOMEGENEOUS DENSITY 2. IRREGULAR SHAPE 3. THICK IRREGULAR MARGINATION 4. INTERNAL HEMORRHAGE OR NECROSIS 5. INVASION OF ADJACENT STRUCTURES
A well recognized feature of benign adenoma (p.797)
STABILITY OVER TIME - absence of change in size and appearance of a small adrenal lesion for 6 months is generally accepted as evidence of BENIGNANCY. - increase in size of the lesion over 6 months is strong evidence of MALIGNANCY.
Patients with hypertension should be evaluated for _____ and _____ (p. 797).
CUSHING and CONN syndromes - Cushing Syndrome is excluded with the absence of HYPERTENSION and OBESITY.
Imaging modality for ADRENAL METASTASES (p.797)
MULTIDETECTOR CT (MDCT)
Non-Contrast CT diagnostic feature of a benign lipid-rich adenoma (70% of patients). CT ATTENUATION? (p.798)
CT ATTENUATION OF LESS THAN 10 H - measurement is made on a thin section through the center of the lesion - range-of-interest(ROI) cursor should cover at least half of the lesion surface; avoiding areas of necrosis or hemorrhage
ADENOMAS are characterized by ____ washout of the contrast agent; ADRENAL METASTASES shows _____ contrast washout (p.798).
RAPID; SLOW
Percentage washout measurements are made on images taken at ________ (p. 798).
60 TO 75 SECONDS FOLLOWING THE ONSET OF INTRAVENOUS CONTRAST INJECTION (ENHANCED ATTENUATION)
DELAYED ATTENUATION MEASUREMENTS are made on images obtained at _____. (p. 798)
10 or 15 minutes following contrast injection
BENIGN ADRENAL LESIONS show ______ absolute percentage washout (APW) and __________ relative percentage washout at 15 minutes (p.798 to 799).
GREATER THAN 60 % (APW); GREATER THAN 40% (RPW)
Chemical shift MR relies on the ______ (p.799)
DIFFERENT PRECESSION FREQUENCIES OF FAT PROTONS VERSUS WATER PROTONS - when fat and water molecules occupy the same voxel; the MR signal from fat and water tend to cancel out each other reducing the signal intensity - CHEMICAL SHIFT MR consists of IP sequences when fat and water signals are additive and OP sequences when fat and water signals are subtractive.
A reduction in signal intensity on OP images as compared to IP images is indicative of _____. (p. 799)
INTRACELLULAR FAT - when evaluating adrenal nodules; the chemical shift MR finding of signal drop indicates a BENIGN LIPID-RICH ADENOMA
Patients with adrenal lesions not characterized by chemical shift MR should be considered for ________ (p. 799)
REPEAT STUDY WITH CONTRAST-ENHANCED CT or PET CT
PET-CT shows high sensitivity in the detection of malignant lesions because of _______ accumulate FDG (p.799-800)
HIGH METABOLIC ACTIVITY
Hemorrhage or necrosis within a metastasis may cause falsely ____ FDG uptake (p.800)
falsely NEGATIVE
Some metastases are false-negative on PET; including those from __ and ___ (p. 800)
NEUROENDOCRINE TUMORS and BRONCHIOALVEOLAR LUNG CA
Some benign lesions include ___ ; ___ and ___ lesions may show slightly increased acitivty in PET-CT (p.800)
- OCCASIONAL ADENOMAS 2. INFECTIOUS 3. INFLAMMATORY
Lesions smaller than __ cm are NOT accurately evaluated by PET (p.800)
1 cm
Adrenal lesions that show more FDG uptake than the liver parenchyma; SUV max greater than 3.1 . BENIGN OR MALIGNANT? (P.800)
MALIGNANT -lesions not categorized by the aforementioned PET-CT methods are considered for follow-up imaging in 4-6 months or for image-guided biopsy
CT-guided adrenal biopsy may be performed using _____ approach or with ____ positioning with adrenal lesions side _____ to diminish the risk of pneumothorax (p. 800)
TRANSHEPATIC approach; DECUBITUS positioning; side DOWN - adrenal biopsy is generally avoided if the lesion Iikely to be a PHEOCHROMOCYTOMA (may precipitate a hypertensive crisis)
______ syndrome is caused by excessive amounts of hydrocortisone and corticosterone released by the adrenal cortex (p. 800)
CUSHING syndrome
__________ causes 70% of cases of non-iatrogenic Cushing syndrome (p.800)
ADRENAL HYPERPLASIA - the hyperplasia is stimulated in 90% of cases by a pituitary macroadenoma that produces adrenocorticotropic hormone (ACTH) - in 10% the source of ACTH is ectopic; usually from lung malignancies
Imaging study racommended for suspected pituitary adenomas (P.800)
MR OF THE SELLA TURCICA
______ causes 20% of cases of Cushing syndrome; and ______ causes the remaining 10 % (p. 800)
BENIGN ADRENAL ADENOMAS; ADRENAL CARCINOMA
Atrophy of the contralateral adrenal gland (in Cushing Syndrome) may be present due to _____ (p.800)
ACTH INHIBITION
______ syndrome produced by elevated levels of aldosterone causes 1% to 2% of systemic hypertension (p.800)
CONN syndrome - persistent hypokalemia; increase serum and urine aldosterone; and decreased renin activity in the plasma (clinical findings)
causes 80% of CONN syndrome ? Causes remaining 20% of CONN syndrome ? (p.801)
solitary; benign; hyperfunctioning ADRENAL CORTICAL ADENOMA; ADRENAL HYPERPLASIA - adenomas are treated with surgical resection - hyperplasia is treated medically
_______ is used to confirm the site of excess aldosterone secretion and to differentiate adenoma from hyperplasia in problem cases (p. 801)
ADRENAL VENOUS SAMPLING
_________ syndrome usualy occurs in newborns and infants who have an ENZYME DEFICIENCY (11 BETA- or 22-HYDROXYLASE); leading to the deficient production of cortisol and aldosterone and an excess of precursors; esp. androgens (p. 801)
ADRENOGENITAL syndrome
_________ refers to primary adrenal insufficiency; which occurs only after 90% of the adrenal cortex is destroyed (p.801)
ADDISON DISEASE - the most common cause in the U.S. is IDIOPATHIC ATROPHY - additional causes involve destruction of the adrenal glands by TB; histoplasmosis; infarction; disseminate fungal infection; lymphoma or metastatic tumor -ADRENAL CALCIFICATION suggests prior TB or HISTOPLASMOSIS - bilateral enlargement is seen in ACTIVE INFECTION - LYMPHOMA and METASTASES replace the gland with tumor
_____ a rare catecholamine-secreting tumor that causes hypertension; headaches; and tremors (p. 801)
PHEOCHROMOCYTOMA - “RULE OF TENS” (10% bilateral; 10% extra-adrenal; 10% malignant; 10% familial; 10% are detected as incidental findings
Pheochromocyctoma is associated with what type of Multiple Endocrine Neoplasia (MEN)? (p. 801)
MEN (MULTIPLE ENDOCRINE NEOPLASIA) II - as well as von Hippel-Lindau syndrome; and neurofibromatosis
Most common adrenal tumor to HEMORRHAGE SPONTANEOUSLY? (P.801)
PHEOCHROMOCYTOMA - CT is the usual imaging method of choice of detecting tumor when clinical manifestations are present - most tumors are larger than 2 cm in diameter - tumors vary from purely solid to complex to predominantly cystic - rare calcifications; but if present usually “eggshell” in configuration - most tumors ENHANCE AVIDLY and WASHOUT SLOWLY similar to malignant lesions
On MR (in Pheochromocytomas); _____ signal ( a “______” lesion) on T2WI is characteristic but seen in only 70% (P.802)
HIGH signal; “LIGHTBULB” lesion
Name 3 extra-adrenal sites for Pheochromocytoma. (p. 802)
- ORGAN OF ZUCKERKANDL near the bifurcation of the aorta 2. BLADDER 3. PARA-AORTIC SYMPATHETIC CHAIN
Radionuclide scans using ____ are also effective in localizing Pheochromocytoma (p.802)
131 I- or 123 I-METAIODOBENZYLGUANIDINE (MIBG)
causes 70% of Cushing Syndrome cases and 20% of Conn Syndrome cases (p. 802)
ADRENAL HYPERPLASIA - usually treated medically when hyperplasia is causative; whereas surgical removal of hyperfunctioning adrenal adenomas is usually curative
Half of the cases of biochemically hyperplastic adrenal glands will appear ______ (p. 802)
ANATOMICALLY NORMAL ON CT AND MR - in the remainder of the cases; both glands will be DIFFUSELY ENLARGED BUT MAINTAIN THEIR NORMAL ADRENAL SHAPE
In DIFFUSE ADRENAL HYPERPLASIA; the limbs of the adrenal glands are longer than ____ cm and exceed ____ - mm thicness (p. 802)
longer than 5 cm; exceed 10 -mm thickness
Name 3 entities that may mimic adrenal hyperplasia or cause diffuse adrenal enlargement (p. 802)
- METASTATIC DISEASE 2. TUBERCULOSIS 3. HISTOPLASMOSIS
________ are rare; non-functioning benign adrenal tumors arising from bone marrow elements in the adrenal gland (p 802)
ADRENAL MYELOLIPOMAS - no malignant potential - they range in size up to 30 cm and frequently inhmogeneous because of their mixed components of marrow fat and hemopoietic tissue - >5 cm lesions have a tendency to hemorrhage - calcifications are present in 20%
Identification of regions of ________ ( ___ to ___ HU) within the tumor by CT or MR is definitive in making the diagnosis of ADRENAL MYELOLIPOMAS (p 802)
MACROSCOPIC FAT ( - 30 to -100 HU) - CT attenuation of less than -30 H is definitive - MR shows high signal fat on T1WI and T2WI ;Fat saturation pulse sequences showing decreased signal confirm the diagnosis - PET: shows no avid FDG uptake - on US; they may be extremely echogenic and blend in retroperitoneal fat
_______ is most common in newborn infants usually induced by episodes of hypoxia; birth trauma or septicemia (p 802)
ADRENAL HEMORRHAGE - on unenhanced CT; hemorrhage shows high attenuation (50 to 90 HU) - hemorrhage on CT is hypodense compared with the liver and spleen on contrast-enhanced studies - most cases are bilateral - in Children; may be associated with CHILD ABUSE - In Adults; blunt trauma (80%) and infection are the most common causes - unilateral hemorrhage is most common in ADULTS; right adrenal gland is most frequently affected - bilateral hemorrahage may cause adrenal insufficiency
Imaging modality that is highly sensitive and specific for adrenal hemorrhage with imaging features dependent on the age of the hemorrhage (p 803)
MR - ACUTE HEMORRHAGE: isointense on T1WI and low intensity on T2WI - SUBACUTE HEMORRHAGE: bright on T1WI and either dark or bright on T2WI - OLD HEMORRHAGE WITH HEMOSIDERIN CONTENT IS LOW SIGNAL: on both T1WI and T2WI US: demonstrates a hypoechoic mass that shrinks and becomes less echogenic over time
Adrenal calcifications ; in both children and adults; most commonly result from ____ (p. 803)
ADRENAL HEMORRHAGE
______ and ______ may cause diffuse adrenal calcification associated with Addison disease (p. 803)
TUBERCULOSIS and HISTOPLASMOSIS
Adrenal tumors that calcify: * in CHILDREN? (Name at least two) * in ADULTS? (Name at least three) (p. 803)
*in CHILDREN: 1. NEUROBLASTOMA 2. GANGLIONEUROMA *in ADULTS: 1. ADRENAL CARCINOMA 2. PHECHROMOCYTOMA 3. GANGLIONEUROMA
most common calcified adrenal masses in ADULTS? (p. 803)
ADRENAL PSEUDOCYSTS ATTRIBUTABLE TO PREVIOUS HEMORRHAGE
_____ is a rare; autosomal recessive lipid disorder associated with ENLARGED CALCIFIED ADRENAL GLANDS; hepatomegaly; and splenomegaly (p803)
WOLMAN DISEASE
[in adrenal cysts] TRUE CYSTS are lined with _____ or _____. PSEUDOCYSTS have a ____ wall without lining cell cells and usually result from ______ or _____. (p 803)
ENDOTHELIUM or EPITHELIUM; FIBROUS; ADRENAL HEMORRHAGE or INFARCTION
Parasitic adrenal cysts are usually _____ in origin. (p. 803)
ECHINOCOCCAL in origin
ADRENAL CYSTS are more common in ____; and may be found in what age? (p. 803)
WOMEN; AT ANY AGE
Adrenal cysts can be classified as UNCOMPLICATED and BENIGN if they have these 4 features? (p. 803)
- THIN WALLS (< 3 MM) WITH OR WITHOUT CALCIFICATION 2. INTERNAL WATER DENSITY 3. DO NOT EXCEED 5 TO 6 CM IN SIZE 4. SHOW NO INTERNAL ENHANCEMENT ON CT MR [UNCOMPLICATED CYSTS]: T1WI - uniform LOW-intensity contents T2WI - uniform HIGH-intensity contents T1C+ - no internal enhancement with gadolinium
TRUE or FALSE? Calcification in adrenal cyst walls and septa is a common finding in all types of cysts (p 803).
TRUE
TRUE or FALSE? Endothelial adrenal cysts tend to be MULTILOCULAR with septal calfifications (p 803).
TRUE
TRUE or FALSE? Hemorrhagic pseudocysts are usually UNILOCULAR with calcification in the wall (p. 803)
TRUE
ADRENAL CYSTS features wherein surgical removal is considered. Name at least 6 of these features. (p. 803)
- CYSTS THAT ARE LARGER THAN 6 CM 2. HAVE THICK WALLS OR SOLID COMPONENTS 3. SHOW INTERNAL CONTRAST ENHANCEMENT ON CT OR MR 4. INHOMOGENEOUS ON MR 5. HAVE ECHOGENIC FLUID OR INTERNAL DEBRIS ON US 6. PRODUCE SYMPTOMS
_____ is a rare benign tumor of the adrenal medulla or paravertebral sympathetic chain; mostly asymptomatic even when large; imaging finding: usually HOMOGENEOUS, OFTEN VERY LARGE (>20 CM) WITH MILD HETEROGENEOUS ENHANCEMENT (P.803)
GANGLIONEUROMA
Typical CT appearance of an ADRENAL CARCINOMA? (p. 803)
LARGE MASS (4 TO 20 CM); WITH AREAS OF CENTRAL NECROSIS AND HEMORRHAGE, SHOWING IRREGULAR ENHANCEMENT - large tumor may be difficult to differentiate from hepatic masses MRI: T1WI: inhomogeneously large mass; predominantly hypointense compared with liver T2WI: increase signal intensity esp. in areas of necrosis - GADOLINIUM ENHANCEMENT or GRADIENT ECHO IMAGING is useful to detect tumor thrombus; US WITH DOPPLER is also excellent for evalution of tumor thrombus PET-CT: shows markedly FDG avidity not only in the tumor but also in mets
[in Adrenal Carcinoma] On delayed post-contrast CT scans; enhament washout is significantly ___ than benign adrenal adenomas; and is ______ to the poor washout of adrenal mets. (p.804)
LESS than; SIMILAR
_________ is rare as a primary adrenal lesion but Hodgkin Lymphoma involves the adrenal in 4% of cases. (p. 804)
- *LYMPHOMA**
- retroperitoneal lymphoma may totally encase the gland CT: lymphoma shows washout characteristics similar to other malignancies MR: shows heterogeneously bright signal on T2WI PET-CT: shows increased FDG uptake
_________ tumor refers to the coexistence of histologically distinct neoplasms that exist separately in the same region (p.804)
- *COLLISION tumor**
- metastatic disease may deposit onto a previously characterized adrenal adenoma - INCREASE IN SIZE OF THE LESION OR SIGNIFICANT CHANGE IN ITS IMAGING CHARACTERISTICS suggests this rare lesion
