Radiological localizing techniques in adrenal tumors

The characterisation of adrenal lesions is a common radiological dilemma. Incidental adrenal lesions are commonly detected with computed tomography (CT), and lesion characterisation is critical. The prevalence of incidental adrenal lesions has been reported to be 2.3% at autopsy and 0.5-2% with abdominal CT. Such lesions are likely to be seen with increasing frequency given the expanding use of radiological imaging in clinical practice. Although the majority of adrenal lesions are benign, in patients with an extra-adrenal primary cancer the probability of an adrenal mass being a metastasis is 52%. Unfortunately, there may be significant overlap between the imaging appearances of benign lesions such as lipid-poor adenomas and malignant lesions, particularly metastases and small adrenal carcinomas. This review highlights recent advances in radiological imaging of adrenal lesions and we discuss the relative merits of CT and magnetic resonance imaging to aid the identification of benign and malignant adrenal lesions and their roles, in combination with biochemical and clinical data, in recognizing common pathologies such as adrenal adenoma, phaeochromocytoma, carcinoma and metastases. We also discuss the radiological characteristics of rarer adrenal lesions including lymphoma, neuroblastic tumours (neuroblastoma, ganglioneuroblastoma, and ganglioneuroma), lipomatous tumours (myelolipoma, angiolipoma, teratoma, lipoma and liposarcoma), in addition to hemangioma, hemangiosarcoma and leiomyosarcoma.

Color-coded duplex endoscopic ultrasound of the adrenals

Imaging of the adrenals by endoscopic ultrasound (EUS) is a valuable technique for detection and localization of adrenal lesions, but endosonomorphological tumor distinction remains difficult. In this single-center study, the amount of blood flow in common adrenal lesions, such as adrenal adenomas, adrenal hyperplasia, and pheochromocytomas, was visualized by color-coded duplex EUS (CD-EUS) and was retrospectively analysed. Therefore, we reviewed our EUS database to evaluate and correlate the perfusion patterns of common adrenal lesions with histologically confirmed diagnosis, possible malignancy, and endosonomorphological features such as echogeneity, echostructure, and tumor size. CD-EUS was performed using an endosonoscope Pentax FG 32 UA with a longitudinal 7.5 MHz sector array and Hitachi EUB 525 ultrasound system. In 38 consecutive patients (male=19; female=19; age: mean 53+/-16 yr SD), perfusion patterns of 46 histologically confirmed adrenal, para- or extra-adrenal lesions of adrenal origin (adenoma: no.=20; nodular hyperplasia: no.=11; pheochromocytoma: no.=15; diameter 26+/-15 mm, range 6-70 mm) were analyzed and classified semiquantitatively as "not" (no.=24), "slightly" (no.=12), "moderately" (no.=4) or "highly" (no.=6) hypervascularized. Compared to adenomas (p=0.003) and nodular hyperplasia (p=0.047), pheochromocytomas showed a significantly higher grade of perfusion. There was no relationship between perfusion patterns and localization of pheochromocytomas (adrenal: 8; paraadrenal: 3; extra-adrenal: 4). Vascularization was not statistically associated with tumor echogeneity, echostructure, malignancy or tumor size. CD-EUS is an additional tool for adrenal endosonographic tumor distinction and seems to improve the endosonographic detection of pheochromocytomas by visualization of hypervascularization. As an overlap of perfusion patterns exists, CD-EUS findings must be interpreted in the context of clinical, laboratory and chemical results.

[CT features of adrenal cortical adenoma: a report of 109 cases]

BACKGROUND & OBJECTIVE

Adrenal cortical adenoma (ACA) is a common disease, and can be diagnosed easily with CT examination. However, some atypical adenomas are likely to be misdiagnosed. This study was to evaluate the common and uncommon CT features of ACA to improve the diagnostic accuracy.

METHODS

Common and uncommon CT features of 109 cases of histologically proved ACA were analyzed.

RESULTS

Of the 109 cases of ACA, 104 showed unilateral single adenoma, 1 showed unilateral 2 adenomas, and 4 showed bilateral adenomas. The maximal diameter of the tumor was <5 cm in 95 patients. The maximal diameter of non-functional adenomas was larger than that of Cushing's adenomas, and the latter was larger than that of Conn's adenomas. The maximal diameter of the tumor was > 5 cm in 14 patients. The probability of degeneration was higher in large adenomas than in small adenomas. The CT images of 85 cases before and after contrast administration were assessed: 74 presented homogenous, 11 presented heterogenous; 76 presented slight to moderate enhancement, and 9 presented remarkable enhancement. Two patients had recurrence after operation: 1 showed infiltration in the adjacent kidney and the psoas major on pathologic examination, 1 showed infiltration in the liver and thoracic vertebra on CT images.

CONCLUSIONS

The common CT features of ACA include unilateral and single lesion, with the maximal diameter of <5 cm, homogenous density before contrast administration, and slight to moderate enhancement after administration. The uncommon CT features of ACA include bilateral or unilateral and multiple lesions, with the maximal diameter of >5 cm, heterogenous density before contrast administration, and remarkable enhancement after administration, recurrence, even canceration, metastasis after operation.

Synchronous Laparoscopic Resection of Colorectal and Renal/Adrenal Neoplasms

Synchronous laparoscopic resections of coexisting abdominal diseases are shown to be feasible without additional postoperative morbidity. We report our experience with synchronous laparoscopic resection of colorectal carcinoma and renal/adrenal neoplasms with an emphasis on surgical and oncologic outcomes. Five patients diagnosed to have synchronous colorectal carcinoma and renal/adrenal neoplasms (renal cell carcinoma in 2 patients, adrenal cortical adenoma in 2 patients, and adrenal metastasis in 1 patient) underwent synchronous laparoscopic resection. The median operative time was 420 minutes and the median operative blood loss was 1000 mL. Three patients developed minor complications, including wound infection in 2 patients and retention of urine in 1 patient. There was no operative mortality. The median duration of hospital stay was 11 days. At a median follow-up of 17.6 months, no patient developed recurrence of disease. Synchronous laparoscopic resection of colorectal and renal/adrenal neoplasms is technically feasible and safe.

Differentiating adrenal adenomas from nonadenomas using (18)F-FDG PET/CT: quantitative and qualitative evaluation

RATIONALE AND OBJECTIVES

We sought to assess the ability of (18)F-fluoro-2-deoxy-d-glucose (FDG) PET/CT to distinguish adrenal adenomas from nonadenomas in patients with suspected malignancy.

METHODS

Fifty-nine adrenal masses were evaluated with coregistered (18)F-FDG PET (PET/CT). Two reviewers independently graded uptake of (18)F-FDG by visual inspection of the adrenal mass in comparison to liver and background. CT attenuation value of the adrenal mass and the standardized uptake value (SUV) of the mass, liver, background, and primary neoplasm (when visible) were measured. Mean SUVs of the adrenal mass, liver, and background and ratios of the SUVs were calculated.

RESULTS

Of 47 adenomas, 43 measured <10 HU on unenhanced CT. Of 12, 12 nonadenomas measured >10 HU on unenhanced CT. Using qualitative assessment of FDG activity in the adrenal mass compared with liver, adenomas were less than, equal to, or more active than the liver in 51%, 38%, and 10%, respectively. Nonadenomas were less than, equal to, or more active than liver in 0%, 25%, and 75%, respectively. The mean SUV of adenomas (4.2) was significantly lower (P = .002) than that of their primary malignancies (9.2) but not that of liver (4.3). The mean SUV of adenomas was not significantly different than that of nonadenomas (5.2), but the mean adrenal/liver ratio (1.0) for the adenomas was significantly lower (P = .006) than that of the nonadenomas (2.1).

CONCLUSION

Adrenal adenomas were better differentiated from nonadenomas using unenhanced CT measurements in combination with ratios of the SUVs. Adrenal mass activity, which was visibly less than liver, was more specific for adenoma, whereas adrenal mass activity visibly greater than liver was more specific for malignancy.

Clinics in diagnostic imaging (113)

Primary hyperaldosteronism is described in a 27-year-old Brazilian woman from an endemic area of schistosomiasis. She presented with hypokalaemia, cramps and polyuria, refractory hypertension, plasma aldosterone of 40.7 ng/dL and aldosterone/renin activity ratio higher than 100, due to an associated long-standing unsuspected aldosteronoma. Computed tomography showed a well-defined ovoid right adrenal mass, which was subsequently resected and confirmed to be an aldosteronoma. During subsequent follow-up visits, she remained asymptomatic, normokalaemic, and required no antihypertensive drugs. The differential diagnoses of refractory hypertension are discussed.

Early severe pre-eclamptic findings in a patient with Cushing's syndrome

Cushing's syndrome occurs rarely in pregnancy because of ovulatory disturbances including anovulation which is caused by hypercortisolism, but it can cause maternal complications such as hypertension, gestational diabetes, spontaneous abortion, premature birth, pre-eclampsia and stillbirth. Herein we present the case of a 22-year-old patient in the 11th week of pregnancy who was admitted to our hospital with Cushing's syndrome complicated by early pre-eclampsia. Severe pre-eclampsia has high maternal and perinatal morbidities, and therefore the possibility of this complication requires that Cushing's syndrome, although rare in pregnancy, be given a high clinical suspicion. Medical therapy and/or surgical therapy should be considered promptly to influence outcome favorably.

Pheochromocytoma associated with adrenocortical tumor in the same gland. Two case reports and literature review

Pheochromocytomas are catecholamine-producing neuroendocrine tumours arising from chromaffin cells of the adrenal medulla or extra-adrenal paraganglionic system that show 2 distinctive features, rarity and clinical variability. Pheochromocytoma occasionally is associated with pathological lesions of the adrenal cortex. We present 2 cases of patients referred to our hospital with a finding of clinical suspected pheochromocytoma. Both of them were hypertensive; the first patient with typical symptoms of pheochromocytoma and the second patient with chest pain and hypertension resistant to pharmacological treatment. The diagnosis of pheochromocytoma was confirmed in both cases with laboratory analysis and the lesion was achieved by employing 3 imaging techniques: computed tomography (CT), magnetic resonance imaging (MRI) and scintigraphy with (123)I-metaiodobenzilguanidine (MIBG). The patients underwent adrenalectomy and in the same adrenal gland we found a pheochromocytoma associated with a nonfunctioning cortical adenoma. As far as we know few cases with this association are available in the literature.

Abrupt enlargement of adrenal incidentaloma: a case of isolated adrenal metastasis

A 56-year-old Japanese man was referred for examination of right adrenal tumor (3 cm). He had no apparent preexisting cancer by radiological workup and accordingly, the patient was considered as a nonfunctioning adrenocortical adenoma and scheduled for periodic CT scans every 6 months. However, five months after the initial diagnosis the patient complained of severe right back pain with remarkable enlargement of both adrenals (~20-fold volume). Although the origin of adrenal tumor was uncertain by pathological workup, positron emission tomography (PET) scan with (18)F-2-fluoro-D-deoxyglucose (FDG) eventually revealed a hot spot on left upper lung, which was consistent with a lesion of thickened bulla wall observed by chest CT. The present case is a very rare example of abrupt enlargement of bilateral adrenals due to clinically isolated adrenal metastasis, suggesting the requirement of frequent observation with greatest care regarding morphologic changes of adrenal incidentalomas.

Non-invasive evaluation of the incidentally detected indeterminate adrenal mass

Clinically silent adrenal masses are discovered incidentally during diagnostic testing or treatment for clinical conditions that are not related to suspicion of adrenal disease; thus, they are commonly referred to as 'incidentalomas'. The widespread use of high-resolution anatomic imaging techniques such as computed tomography (CT) and magnetic resonance (MR) imaging has led to the increased detection of these masses. In many patients without a known extra-adrenal primary malignancy--and even in patients with a primary neoplasm--most adrenal masses ultimately prove to be benign. However, it remains important that these adrenal masses are accurately characterized to exclude the treatable causes of adrenal disease, and also to accurately stage the oncology patient. The purpose of this chapter is to describe the findings and recent advances in non-invasive imaging methods that are now available for the accurate characterization of incidentally detected adrenal masses (i.e. the differentiation of benign from malignant masses). The imaging techniques and the algorithms that are used in our institution for the evaluation of incidentally detected adrenal mass will be described.

Adrenal pheochromocytoma with contralateral cortisol-producing adrenal adenoma: diagnostic and therapeutic management

There is evidence for a close interrelation between the adrenomedullary and adrenocortical tissues, and there are well-characterized models of their paracrine interaction. To contribute to the studies of systemic interactions between these tissues, we studied a 52-year-old female patient with a pheochromocytoma and a contralateral cortisol-producing adenoma. Due to a misunderstanding, she presented to her family doctor to have an inherited kidney disease ruled out. An adrenal mass was discovered incidentally by ultrasound. A computerized tomography of the abdomen revealed bilateral adrenal masses. Due to excess catecholamine secretion, bilateral pheochromocytomas based on multiple endocrine neoplasia syndrome were suspected. Laboratory work-up, selective adrenal venous sampling and magnetic resonance imaging studies established the diagnosis of a pheochromocytoma in the right-hand adrenal gland and a cortisol-producing adenoma on the left. Simultaneous bilateral laparoscopic subtotal adrenalectomy was performed. Immunohistochemistry showed positive staining against chromogranin A in a histological specimen obtained from the right-hand adrenal gland, while the left was negative; the left-hand adrenal gland stained positive against the ACTH receptor (MC2R) while the right was negative. Genetically, the patient was negative for MEN2, von Hippel-Lindau disease, and mutations in subunits B, C, and D of the succinate dehydrogenase gene. Although presence of bilateral adrenal adenomas or bilateral adrenal pheochromocytomas in certain inherited disorders are possible, this rare case of an adrenal pheochromocytoma combined with a contralateral cortisol-producing adrenal adenoma may further underline the wide range of complex interactions between the two endocrine systems.

Congenital adrenocortical adenoma: case report and review of literature

Congenital ardrenocortical neoplasms are exceedingly rare. Our review of the medical literature revealed 23 reported cases of adrenocortical neoplasm including this one. Eighteen of these cases were adrenocortical carcinoma and four were grouped as adrenocortical tumor. We have not found any reported case with a histological diagnosis of a congenital adrenocortical adenoma. We present this case of a congenital adrenocortical neoplasm with histological findings consistent with an adrenocortical adenoma in a premature infant aged 27 weeks and 4 days who had a prenatal sonogram showing a cystic right abdominal mass and a physical examination demonstrating a palpable mass.

F-18 Fluorodeoxyglucose Positron Emission Tomography-Positive Benign Adrenal Cortical Adenoma: Imaging Features and Pathologic Correlation

Accurate characterization of adrenal lesions in lung cancer is essential in the staging of the disease. Computed tomography and magnetic resonance imaging as well as fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging are used to differentiate adrenal metastases from benign adenomas. Although FDG-PET is highly accurate in this regard, benign adrenal cortical adenomas have been shown to accumulate FDG, although to a lesser degree. We present a patient with a history of lung cancer and FDG accumulation in a benign adenoma, probably reflecting areas of chronic inflammation also seen within the gland at pathology.

Computed tomography-guided percutaneous acetic acid injection therapy for functioning adrenocortical adenoma

We reported the outcomes of computed tomography (CT)-guided percutaneous acetic acid injection therapy for functioning adrenocortical adenomas. With the patient in a prone position, the puncture needle was inserted vertically downward into the adenoma with frequent CT scanning. After confirmation by pilot injection with contrast medium, a small aliquot of 40-50% acetic acid was injected and repeated. Between 1997 and 2002, 18 sessions of CT-guided injection therapy, including one session of ethanol injection, were performed on 10 patients (five patients with primary aldosteronism and five patients with Cushing's or subclinical Cushing's syndrome) without any complications except transient upper abdominal pain during the acetic acid injection. The follow-up period ranged from 5-69 months. The treatment resulted in almost an extirpation of the adrenocortical hyperfunction in seven patients after one or two sessions. CT-guided percutaneous acetic acid injection might be a simple, cost-effective, and far less invasive treatment for small functioning adrenocortical adenomas.

46, XY agonadism associated with adrenal adenoma/myelolipoma: report of a case analyzing Y-chromosome-specific sequences

A unique patient with 46, XY agonadism associated with adrenal adenoma/myelolipoma is described. The patient was an 18-year-old female with primary amenorrhea, lack of secondary sexual development and an aldosterone-producing adrenocortical adenoma associated with foci of myelolipoma. Molecular analyses of Y-chromosome-specific regions, including automated sequencing of the entire coding region of SRY, the Y-linked testis-determining gene, were performed. Our results excluded the possibility that a mutation in SRY was responsible for this unusual clinical combination.

CT of primary hyperaldosteronism (Conn's syndrome): the value of measuring the adrenal gland

OBJECTIVE

The objectives of our study of patients with primary hyperaldosteronism (Conn's syndrome) were to determine whether the adrenal glands are larger in patients with bilateral adrenal hyperplasia than in those with aldosterone-producing adenomas or in healthy control subjects; and whether a CT criterion based on adrenal gland size can be developed to positively diagnose bilateral adrenal hyperplasia.

MATERIALS AND METHODS

A retrospective study of CT scans of 28 patients with primary hyperaldosteronism was performed. The means of two observers' measurements of adrenal gland size were recorded and compared with published normal values. In addition, a radiologist experienced in adrenal imaging and unaware of the cause of the primary hyperaldosteronism diagnosed either bilateral adrenal hyperplasia or aldosterone-producing adenoma by visual inspection.

RESULTS

The adrenal glands in patients with bilateral adrenal hyperplasia were significantly (p < 0.05) larger than those in patients with aldosterone-producing adenoma or in healthy control subjects. A sensitivity of 100% was achieved when a mean limb width of greater than 3 mm was used to diagnose bilateral adrenal hyperplasia, and a specificity of 100% was achieved when the mean limb width was 5 mm or greater. Receiver operating characteristic curve analysis showed that the overall performance of the radiologist and the mean adrenal limb width in detecting bilateral adrenal hyperplasia were equivalent.

CONCLUSION

In patients with primary hyperaldosteronism, adrenal limb measurements on CT can aid in differentiating bilateral adrenal hyperplasia from aldosterone-producing adenoma because the adrenal glands in bilateral adrenal hyperplasia are larger.

High [18F] 2-fluoro-2-deoxy-D-glucose (FDG) uptake of adrenocortical adenoma showing subclinical Cushing's syndrome

A 48-year-old woman with left adrenal tumor, which showed increased uptake of [18F] 2-fluoro-2-deoxy-D-glucose (FDG) was presented. Her adrenal tumor was incidentally discovered, although she had no remarkable illness, and her blood pressure was normal. Hormonal examination including dexamethason suppression test and diurnal variation in serum cortisol level confirmed preclinical Cushing's syndrome. CT, MRI and 131I-adosterol scintigraphy showed findings consistent with adenoma. FDG-PET revealed that tumor had standardized uptake value of 4.8, which was higher than usual benign tumors. Histological diagnosis of the resected adrenal tumor was adrenocortical adenoma without evidence of malignancy. Although the current literature showed that adenomas in general did not exhibit increased FDG uptake, adenoma in the present case with subclinical Cushing's syndrome showed intense uptake of FDG, suggesting FDG-PET could evaluate hormonal function of an adrenocortical adenoma in a completely asymptomatic normocortisolism patient.

A case of Cushing s syndrome in pregnancy secondary to an adrenal cortical adenoma

Cushing s syndrome in pregnant women is rare and difficult to be diagnosed because of the syndrome's association with oligomenorrhea or amenorrhea and the changes in cortisol metabolism during normal pregnancy. Cushing syndrome in pregnancy is usually confused with complicated pregnancy, such as preeclampsia or gestational diabetes, and its rarity leads to a low degree of clinical suspicion, often delaying diagnosis. We experienced a case of Cushing s syndrome in pregnancy, which had been considered as the severe preeclampsia and gestational diabetes due to uncontrolled hypertension and hyperglycemia. The pregnancy was terminated with an emergency cesarean operation at 30 weeks of gestation because of severe preeclampsia. In consequence of the evaluation about the Cushing s syndrome after delivery, the adrenal cortical adenoma of right adrenal gland was diagnosed and laparoscopic adrenalectomy was performed.

[Hyperaldosteronism persisting after subtotal adrenalectomy]

BACKGROUND

Primary aldosteronism is known to be caused by aldosterone-producing adenoma (APA). Total adrenalectomy is the standard procedure. In contrast to bilateral adrenal diseases (e.g., MEN II pheochromocytomas), there is no consensus about the effect of subtotal adrenalectomy.

CASE REPORT

A 44-year-old patient with primary aldosteronism caused by APA underwent subtotal adrenalectomy including removal of one adenoma. Because hypertension and hypokalemia did not disappear and hyperaldosteronism persisted, the patient had to undergo reoperation in which the adrenalectomy was completed.

DISCUSSION

Subtotal adrenalectomy in patients with Conn's syndrome is an interesting therapeutic option,whereas its effect is much higher in hereditary diseases of the adrenal gland. The benefit of preserved adrenal tissue has to be weighed against a possible persistence of hyperaldosteronism, especially in cases with normal opposite adrenal glands.

Non-functional adrenocortical adenoma with extensive degeneration

We report a case of non-functional adrenocortical adenoma of 5.5 x 5.5 x 3.2 cm in size that had an unusual histopathological appearance in two respects. First, the tumor contained small adipose foci with osteogenesis and was suspected of being a myelolipoma based on its appearance on computerized tomography (CT) and magnetic resonance imaging. However, pathologically, the fat element was seen focally and was not accompanied by hematopoietic cells, and the diagnosis of myelolipoma was abandoned. Second, the tumor was suspected of being an adrenal carcinoma based on its appearance on CT scans and showed extensive degeneration: fibrosis, hemorrhage, loss of parenchyma and moderate atypism of the tumor cells. However, as the architecture of the tumor cells was non-diffuse and there were no necrotic foci or mitoses, and vascular or capsular invasion were not present, the tumor was concluded to be an adrenocortical adenoma rather than a carcinoma. We diagnosed the tumor as a non-functional adrenocortical adenoma with extensive degeneration as the extensive areas of fibrosis were particularly remarkable. Furthermore, the extensive areas of degeneration might have been caused not only by an ischemic effect but also by low hormone levels.

Clinical and histopathological evaluation of the adrenal incidentaloma

Clinically silent adrenal masses (incidentaloma) are incidentally discovered lesions, when noninvasive imaging methods (USG, CT, MRI) are performed for reasons other than known or suspected adrenal disease. Most studies report on a prevalence of adrenal incidentaloma range between 1% and 10% in radiological series. Between 1994 and 1999 we observed in our Department 57 patients with incidentalomas of adrenal glands. After endocrinological evaluation silent Cushing's syndrome was found in 2 cases (3.5%). Fifty two patients were qualified for surgery. Adrenocortical adenoma was diagnosed in 73.1%; adrenocortical carcinoma in 7.7%; pheochromocytoma in 7.7% and less frequent adrenal lesions in 11.5%. All adrenal carcinomas and malignant pheochromocytomas (11.5%) were found in tumors with diameter over 4 cm.

Relationship between clear cell/compact cell ratio and computed tomographic attenuation number in adrenocortical adenoma

Clear cell/compact cell ratio in histologic sections from 21 resected adrenocortical adenomas was assessed. Seven patients had Cushing's syndrome another 7 had primary aldosteronism caused by adrenal adenomas and 7 had non-hyperfunctioning adenomas. The results were correlated with the corresponding unenhanced CT attenuation numbers. There was a negative correlation between clear cell/compact cell ratios and unenhanced CT attenuation numbers. However, CT attenuation numbers did not show significant differences between cortisol-producing, aldosterone-producing and nonfunctioning adenomas. These facts suggest that clear cell/compact cell ratio in adrenocortical adenomas accounts for their attenuation number on unenhanced CT scans. However, it is difficult with the use of unenhanced CT attenuation numbers to differentiate cortisol-producing adenomas from aldosterone-producing and nonhyperfunctioning adenomas.

PET imaging of adrenal cortical tumors with the 11beta-hydroxylase tracer 11C-metomidate

The purpose of the study was to evaluate PET with the tracer 11C-metomidate as a method to identify adrenal cortical lesions.

METHODS

PET with 11C-metomidate was performed in 15 patients with unilateral adrenal mass confirmed by CT. All patients subsequently underwent surgery, except 2 who underwent biopsy only. The lesions were histopathologically examined and diagnosed as adrenal cortical adenoma (n = 6; 3 nonfunctioning), adrenocortical carcinoma (n = 2), and nodular hyperplasia (n = 1). The remaining were noncortical lesions, including 1 pheochromocytoma, 1 myelolipoma, 2 adrenal cysts, and 2 metastases.

RESULTS

All cortical lesions were easily identified because of exceedingly high uptake of 11C-metomidate, whereas the noncortical lesions showed very low uptake. High uptake was also seen in normal adrenal glands and in the stomach. The uptake was intermediate in the liver and low in other abdominal organs. Images obtained immediately after tracer injection displayed high uptake in the renal cortex and spleen. The tracer uptake in the cortical lesions increased throughout the examination. For quantitative evaluation of tracer binding in individual lesions, a model with the splenic radioactivity concentration assigned to represent nonspecific uptake was applied. Values derived with this method, however, did show the same specificity as the simpler standardized uptake value concept, with similar difference observed for cortical versus noncortical lesions.

CONCLUSION

PET with 11C-metomidate has the potential to be an attractive method for the characterization of adrenal masses with the ability to discriminate lesions of adrenal cortical origin from noncortical lesions.

Laparoscopic ultrasound imaging of adrenal tumors during laparoscopic adrenalectomy

BACKGROUND

The purpose of this study was to determine the usefulness of laparoscopic ultrasound (LUS) during laparoscopic adrenalectomy (LA) and to define the ultrasound imaging characteristics of various adrenal tumors.

METHODS

LUS was utilized in 27 patients who underwent LA (including one bilateral adrenalectomy) from May 1994 to October 1998. Tumor size ranged from 1.0 to 5.5 cm (mean 3.3 cm), and a transabdominal lateral approach to LA was used.

RESULTS

LUS localized the adrenal gland and tumor in all 28 adrenalectomies and demonstrated the relationship of the tumor to the kidney and adjacent vascular structures (renal artery/vein and inferior vena cava). The adrenal vein was visualized sonographically in only six cases (21 %). Pheochromocytomas were mild to markedly heterogenous, whereas most aldosteronomas and cortical adenomas were homogenous. LUS provided useful information to the surgeon in 11 of 28 cases (39%) by: 1) localizing the adrenal gland and tumor and/or guiding the dissection; 2) demonstrating that tumors > or =4 cm were confined to the adrenal gland; and 3) investigating suspected pathology in other organs. Mean operating time for LUS was 10.9 min (range 5 to 24 min) and calculated hospital charges were $602.

CONCLUSIONS

LUS accurately localizes adrenal tumors, helps define their relationship to adjacent structures, and provides confirmation that larger tumors are amenable to laparoscopic resection. LUS is a useful adjunct to laparoscopic adrenalectomy in selected patients.

Small functional adrenal cortical adenoma: treatment with CT-guided percutaneous acetic acid injection--report of three cases

Two patients with Conn syndrome and one patient with Cushing syndrome underwent computed tomography (CT)-guided tumor ablation with a total of 5-11 mL of 50% acetic acid injected into their adrenal nodule (1.3-3.3 cm in diameter). No major complications were encountered during or after the procedure. All patients were symptom free with normal laboratory test results for at least 1-year follow-up. CT images showed complete cystic change with tumor size regression. Our preliminary results suggest that percutaneous acetic acid injection is a safe and effective alternative for treatment of small functional adrenal cortical adenoma.

Clinics in diagnostic imaging (39). Conn's syndrome due to adrenocortical adenoma (Conn's tumour)

A 33-year-old man presenting with muscle weakness and hypertension was found to have hypokalaemia and metabolic alkalosis. Computed tomography (CT) showed an adrenal mass. Conn's syndrome due to an adrenocortical adenoma was confirmed at surgery. Hypertension-related adrenal disorders such as Cushing's syndrome, carcinoma and phaeochromocytoma are discussed. CT is currently the single most useful imaging method for identifying adrenal masses.

Large degenerated adrenal adenomas: radiologic-pathologic correlation

PURPOSE

To correlate the radiologic and pathologic findings and differential diagnosis of large, degenerated adrenal adenomas.

MATERIALS AND METHODS

The authors reviewed the radiologic and pathologic characteristics of 30 large adenomas with cystic regions or areas of heterogeneity that were either intrinsic or demonstrated at contrast material-enhanced computed tomography (CT) or magnetic resonance (MR) imaging. Images of 24 adrenocortical carcinomas were also reviewed to determine whether differentiating characteristics existed.

RESULTS

Most of the adrenocortical adenomas were in asymptomatic women. Ten adenomas contained calcification. Pathologic examination revealed good correlation between heterogeneity and liquefied regions. Histologic examination confirmed regions of adenomatous tissue with areas of hemorrhage, amorphous degenerated material, calcification, and fibrosis. Some tumors contained myelolipomatous foci. Although some clinical and imaging findings differed between the groups, no features could be found that enabled the radiologic differentiation of adenomas from carcinomas.

CONCLUSION

A subgroup of adrenal adenomas are larger, more heterogeneous, and more frequently calcified than those with the usual imaging findings. Central necrosis, hemorrhage, or both are responsible for many of the imaging features. Differentiation of these lesions from other large adrenal masses, including adrenal carcinoma, cannot be made by means of imaging alone; resection is required for the definitive diagnosis.

Spectrum of CT findings in nonmalignant disease of the adrenal gland

Computed tomography (CT) plays a leading role in the evaluation of nonmalignant disease of the adrenal gland. CT is highly accurate in the localization of adrenal masses in patients with diseases associated with hyperfunctioning adrenal glands such as Cushing syndrome and Cushing disease, Conn syndrome, adrenal tumors leading to virilization or feminization, and pheochromocytomas. CT permits a specific diagnosis of acute or subacute adrenal hematoma and myelolipoma. Hematomas are round to oval and have increased attenuation (50-90 HU) that decreases on follow-up CT scans. Myelolipomas typically manifest as a well-defined suprarenal mass with an attenuation of-30 to -115 HU. Adrenal cysts are usually round to oval and manifest as a hypoattenuating mass with a smooth, thin wall. CT is useful in the evaluation of patients with Addison disease, particularly the subacute form secondary to tuberculosis or disseminated histoplasmosis. Findings typically include bilateral adrenal enlargement with a central necrotic area of hypoattenuation and peripheral enhancement. Thin-section unenhanced CT permits accurate measurement of attenuation and can be used to differentiate adrenal adenoma from metastasis in a cancer patient with an indeterminate mass: Attenuation of 10 HU or less usually indicates adenoma rather than cancer. If the mass is found incidentally at contrast material-enhanced CT, delayed scans obtained as early as 5-15 minutes after intravenous administration of contrast material appear to have comparable accuracy.

Unique association of pheochromocytoma with contralateral nonfunctioning adrenal cortical adenoma

A 57-year-old woman complaining of hypertensive attacks associated with headache and palpitation was admitted to our hospital for examination of bilateral adrenal tumors in 1985. After right pheochromocytoma was diagnosed, right adrenalectomy was performed. The left adrenal tumor was small; thus, the left adrenal tumor was preserved to avoid adrenal insufficiency, although left adrenal pheochromocytoma could not be denied. In 1995, she was referred to our clinic again because of recurrent headache and palpitation, and enlargement of the left adrenal tumor. Although pheochromocytoma was suspected again, the enlarged left adrenal turned out to be a nonfunctioning cortical adenoma. This case was interesting, not only because of difficulty in identifying the left adrenal tumor, but also because of the rare coexistence of a pheochromocytoma and a nonfunctioning adrenal cortical tumor.

Scintigraphic assessment of therapeutic success in aldosteronomas treated by transcatheter arterial embolization using absolute ethanol

Adrenocortical scintigraphy was examined as an indicator of therapeutic success in aldosteronomas treated by transcatheter arterial embolization (TAE) with absolute ethanol (AE).

METHODS

Adrenocortical scintigraphy was performed 7 days after intravenous injection of 37 MBq 131I-6-beta-iodomethyl-19-norcholesterol before and after TAE. Complete or incomplete therapeutic success was determined by periodic measurements of the levels of plasma aldosterone and correlated with the scintigraphic results.

RESULTS

The aldosteronoma was visualized as a hot nodule in nine patients and a warm nodule in one patient before TAE. Scintigraphy showed a hot, residual hot or warm nodule on seven occasions (six occasions after the first TAE and one occasion after the second TAE) when the techniques were incompletely successful and disappearance on seven occasions when success was achieved (three occasions after the first TAE and one occasion after the second TAE). Of the seven occasions when TAE was unsuccessful, four patients received the second or third TAE to result in complete destruction of the aldosteronoma; three patients underwent unilateral adrenalectomy.

CONCLUSION

Adrenocortical scintigraphy can correctly predict the effect of TAE on aldosteronomas and is a valuable indicator for decisions on the necessity of repeated TAE or adrenalectomy.

Adrenocortical adenoma producing 18-hydroxycorticosterone

A 30-year-old man presented at our hospital with microscopic hematuria. Ultrasonography and computed tomography scanning revealed a right adrenal mass measuring 20 x 20 mm. The tumor was asymptomatic, but there was obvious accumulation on the right side when scintigraphy was performed with radioactive iodine (131I)-labeled adosterol. Endocrinology studies showed elevation of the plasma cortisol and renin concentrations, while the plasma aldosterone level was low. Right laparoscopic adrenalectomy was done on July 4, 1994. Histologic examination showed an adrenocortical adenoma. Serum levels of adrenocortical hormones were measured before and after surgery, and the tissue content for the same hormones was determined in the resected tumor. The hormonal studies showed that the tumor produced 18-hydroxycorticosterone.

Bilateral deoxycorticosterone-secreting adrenocortical adenoma

A case of a 58-year-old man with bilateral deoxycorticosterone (DOC)-secreting adrenocortical adenoma is reported. Before surgery, plasma levels of DOC and corticosterone were markedly elevated, but both adrenal hormone levels normalized after the surgical removal of the bilateral adrenal tumors. The histologic examination revealed bilateral adrenocortical adenoma, but curiously, the tissue concentrations of DOC and corticosterone were elevated only in the right adrenal gland.

Simultaneous scintigraphic depiction of aldosteronoma and adrenal infarction

Primary aldosteronism is a potentially curable cause of hypertension, especially when caused by an adrenal adenoma. Aldosteronomas because of their small size often elude techniques to locate them. This case illustrates the advantages, disadvantages and complications of noninvasive techniques used for their diagnosis. A patient with hypertension and hypokalemia underwent an adrenal venous effluent sampling for measurement of aldosterone concentrations. This procedure was complicated by an injury to the right adrenal gland. Subsequently, it was difficult to control the patient's hypertension and hypokalemia with medical therapy alone. A re-assessment years after his initial diagnosis included a CT scan, which now visualized a left adrenal tumor. The functional status of this tumor and lack of function of the previously injured right adrenal gland were demonstrated by NP-59 scintigraphy. This information modified the surgical intervention (adenectomy rather than total adrenalectomy) and the residual left sided adrenal tissue prevented adrenocortical insufficiency. A year later the patient remains euadrenal.

Differentiation of adrenal adenomas from nonadenomas using CT attenuation values

OBJECTIVE

The purpose of our study was to determine whether unenhanced CT attenuation value, enhanced CT attenuation value, or lesion size can be used to differentiate adrenal adenomas from nonadenomatous adrenal masses.

MATERIALS AND METHODS

We retrospectively assessed the CT scans of 135 adrenal masses in 124 patients with a variety of adrenal masses. There were 93 cortical adenomas (85 nonhyperfunctioning adenomas, four Cushing's adenomas, and four primary aldosteronism adenomas). The nonadenomas consisted of 34 metastases, four cortical carcinomas, and four pheochromocytomas. The scattergrams and mean values of the size and attenuation values on enhanced and unenhanced scans were correlated with the final diagnoses. Results were also subjected to receiver operating characteristic analysis.

RESULTS

Forty-one adenomas and 20 nonadenomas had unenhanced CT. The mean attenuation value of the 41 adenomas was significantly lower (p < .001) than that of the nonadenomas (2.5 H +/- 14 compared with 32 H +/- 6.4). The lowest unenhanced CT attenuation value of the nonadenomas was 18 H; therefore, the sensitivity:specificity ratio for the diagnosis of adenomas was 85%:100% at a threshold value of 18 H. At this threshold, the positive predictive value was 100% and the negative predictive value was 77%. For the 85 masses with enhanced CT, the mean attenuation of the 60 adenomas was also significantly lower (p < .01) than for the 25 nonadenomas (47 H +/- 24 compared with 62 H +/- 21). The lowest enhanced CT attenuation value of the nonadenomas was also 18 H, but the sensitivity:specificity ratio was only 10%:100% at this threshold value of 18 H. Although the mean diameter of the adenomas was significantly lower (p < .001) than for the nonadenomas (2.4 cm +/- 0.9 compared with 4.5 cm +/- 2.5), there was sufficient overlap between the two groups at the smallest sizes that a threshold value for a highly specific diagnosis of adenoma was not present. The area under the receiver operating characteristic curve for unenhanced CT attenuation values (0.98 +/- 0.02) was significantly greater than the area for enhanced CT values (0.68 +/- 0.06, p < .001) and the area for size (0.79 +/- 0.04, p < .001).

CONCLUSIONS

Unenhanced CT attenuation values can characterize an adrenal mass as a benign adenoma with high specificity and acceptable sensitivity. Adrenal masses cannot be characterized using enhanced CT attenuation values or lesion size.

Tumours of the adrenal cortex

The authors report their experience of 34 benign and 17 malignant tumours of the adrenal cortex. Both occurred more frequently in women (79.4% of cortical adenomas and 70.6% of adrenocortical carcinomas). Moreover, females were significantly younger (average age: adenomas: females 44.9 years and males 54.4 years, adrenocortical carcinomas: females 34.1 years and males 58.3 years). Some tumours presented in the form of increased hormone production, while others were hormonally inactive and did not cause clinical signs until later. Pain was the first symptom in the cases of malignant adrenocortical tumours. Adenomas occurred as frequently twice in the left adrenal gland (24 versus 12), whereas carcinomas were more than twice are frequent on the right (10 versus 7). Ultrasonography and CT were appropriate and fully sufficient methods for the diagnosis of adrenal tumours. Arteriography was valuable in the differential diagnosis of large upper abdominal masses when the organ of origin could not be identified by CT and for determination of anatomic conditions and subsequent surgical tactics. For small tumours of the adrenal cortex, the classic lumbar approach through the bed of the resected eleventh rib is adequate. For larger tumours, extended lumbotomy, laparotomy or thoracotomy is necessary.

Adrenal nonhyperfunctioning adenoma and nonadenoma: CT attenuation value as discriminative index

BACKGROUND

When an asymptomatic adrenal mass is incidentally discovered on abdominal CT scans, the distinction between a nonhyperfunctioning adenoma and a nonadenoma would be important.

METHODS

We evaluated the CT findings of 36 adrenal masses (14 nonhyperfunctioning adenomas, 22 nonadenomas) in 34 patients with no evidence of hormonal hypersecretion. CT attenuation values of adrenal masses on CT scans were calculated by setting a circular region of interest as large as possible in the center of each adrenal mass.

RESULTS

Below 20 HU in CT attenuation values, all adrenal masses, except one case of ganglioneuroma with myxomatous change, were nonhyperfunctioning adenomas. With an arbitrary threshold of 20 HU, the sensitivity of CT attenuation values in distinguishing nonhyperfunctioning adenomas from nonadenomas was 64%, the specificity was 95%, and the accuracy was 83%. When decreasing the threshold to 15 HU, the sensitivity was 64%, the specificity was 100%, and the accuracy was 86%. The CT attenuation value on noncontrast CT was more useful for making this distinction than the size and interior homogeneity.

CONCLUSIONS

Our data suggest that an asymptomatic adrenal mass with homogeneous low attenuation (< or = 15 HU) and less than or equal to 4 cm indicates a nonhyperfunctioning adenoma, and no further examinations are necessary. CT attenuation value on non-contrast CT is the most important discriminatory factor.