Imaging of adrenal masses

PURPOSE OF REVIEW: This review aims to outline recent developments in adrenal imaging and characterization. Controversies in the management of adrenal incidentalomas will be addressed. RECENT FINDINGS: Evaluation of density readings on unenhanced computed tomography and on contrast-enhanced delayed series has tremendously improved the characterization of adrenal masses. Attenuation measurements may, however, vary between different scanner types and may also be influenced by patient factors and the scanning technique. Evaluation of the mean percentage washout for adrenal masses on delayed enhanced computed tomography series is independent of such factors and allows the characterization of adrenal lesions with high sensitivity and specificity. In magnetic resonance imaging, dynamic gadolinium-enhanced and chemical-shift techniques have significantly improved the characterization of adrenal masses. Nuclear medicine studies prove to be useful adjuncts. Controversial reports have been published on the role of positron emission tomography/computed tomography in adrenal imaging. Adrenal venous sampling may allow differentiation of aldosteronoma and idiopathic hyperaldosteronism. SUMMARY: Recent developments in adrenal mass imaging have improved the characterization of adrenal mass lesions. The need for histology sampling of incidentally discovered adrenal masses has been significantly reduced due to the high specificity of these new techniques. Controversies still exist regarding the optimal strategy for hormonal screening of a patient with an incidentally detected adrenal mass.     

Incidentally discovered adrenal masses

It is becoming increasingly common to discover adrenal masses incidentally on radiologic imaging studies. Adrenal masses are also occasionally found unexpectedly during operation. Herein, we review 10 cases of incidentally discovered adrenal masses which illustrate the experience with the treatment of these lesions in the past 8 years. A management plan based on this experience and a review of previously published data are discussed.     

Needlescopic ablation of small adrenal masses

Needlescopic adrenal ablative therapy is an attractive therapeutic option for the management of small adrenal masses. The spectrum of neoplasms that can be ablated includes isolated solid organ metastases (lung, kidney, liver), nonisolated but symptomatic (painful) adrenal metastasis, and small, nonmetastatic, hormonally active adrenal tumors. Moreover, needlescopic ablation offers an effective minimally morbid intervention for patients who are poor surgical candidates either due to advanced age and/or significant comorbid conditions. Ablative techniques described to date include radiofrequency ablation (RFA), cryoablation, and chemical ablation. Most procedures can be performed under percutaneous radiographic guidance on an outpatient basis. By and large, the bulk of clinical experience with adrenal ablation pertains to RFA. Successful ablation is usually dependent upon lesion size, with tumors 5 cm or smaller demonstrating the highest successful ablation rates. The most frequently described adverse sequelae of adrenal ablation are local tumor recurrences. However, many of these local recurrences can be managed by repeat ablation, with patients demonstrating durable oncologic outcomes.     

Management of incidentally discovered adrenal masses

The incidental discovery of adrenal masses in radiologic imaging studies is becoming increasingly common. Herein we present our experience with 59 cases of incidentally discovered and surgically removed adrenal masses. Of 59 adrenal incidentalomas, 15 cases were hypersecretory tumors, including 11 pheochromocytomas; only 3 were adrenocortical carcinomas. The prevalence of incidentally discovered adrenal masses and their differential diagnosis and management are discussed in a review of the literature.     

Computed tomography evaluation of adrenal masses

Computed tomography is the first line modality in the evaluation of patients with adrenal gland masses, and has the potential to be very accurate in the localization of adrenal gland masses in patients with diseases associated with hyperfunctioning conditions of the adrenal gland. Computed tomography allows a specific diagnosis of acute adrenal haemorrhage, adrenal myelolipoma, and adrenal cysts. It is also helpful in the assessment of patients with Addison's disease, particularly the subacute form secondary to granulomatous diseases. Quantitative evaluation of adrenal masses on unenhanced or delayed-enhanced computed tomography has been shown to be highly accurate in distinguishing adrenal adenomas from non-adenomas. Attenuation of 18 HU or less on unenhanced computed tomography scans indicates adenoma with a high specificity and acceptable sensitivity. On delayed-enhanced computed tomography scans, adrenal adenomas exhibit a greater washout of contrast material than do adrenal non-adenomas. Therefore, adrenal non-adenomas have significantly higher attenuation than adenomas on delayed-enhanced computed tomography scans obtained at arbitrarily chosen times (3-60 min) after the initiation of contrast material administration.     

Laparoscopic adrenalectomy for large adrenal masses

Open adrenalectomy has been the gold-standard therapy for adrenal neoplasms. Minimally invasive treatments, however, have assumed a more central role in the management of these lesions. The traditional benefits of laparoscopy, including reduced blood loss, shorter hospital duration, and improved convalescence, extend to adrenal disease without compromising the oncologic efficacy of the surgery. Contemporary series suggest that minimally invasive surgery is also a reasonable therapeutic modality for larger adrenal masses. Laparoscopic adrenalectomy for these large masses is a technically demanding procedure that should be undertaken by experienced laparoscopic surgeons familiar with retroperitoneal anatomy and adept with vascular techniques in the event of an open conversion. Oncologic outcomes collectively suggest that in the setting of adequate surgical resection, recurrence patterns relate more to disease-process biology than surgical approach. Neither size criteria, suspicion of malignancy, nor locally invasive disease should be considered an absolute contraindication to laparoscopic adrenalectomy.     

Current concepts in imaging of adrenal masses

Adrenal masses are a common entity. With the advent of improved cross-sectional imaging techniques the detection and characterization of adrenal masses has improved dramatically. We review the imaging features of benign and malignant adrenal masses and other entities that may cause mass-like enlargement of the adrenal glands.     

Differentiation of adrenal masses by magnetic resonance imaging

Eighty-one adrenal masses in 68 patients were examined with magnetic resonance imaging (MRI). Masses included nonfunctioning adenomas (17), metastases (25), adrenocortical carcinomas (10), and pheochromocytomas (23). T1-weighted pulse sequences depicted the anatomy with a resolution comparable to that of computed tomography (CT). T2-weighted pulse sequences provided some histologic specificity separating nonfunctioning adenomas with low signal-intensity from metastases with intermediate signal-intensity and pheochromocytomas with high signal-intensity. Pheochromocytomas could always be distinguished from other adrenal masses. In 20% of the cases, metastases with low signal-intensity could not be distinguished from nonfunctioning adenomas.     

Feasibility of laparoscopic adrenalectomy for large adrenal masses

Laparoscopic adrenalectomy (LA) is a preferred method for the removal of small adrenal masses. However, the role of LA for surgical treatment of large adrenal masses is less established. We evaluated the outcomes of LA for large (>/=5 cm) adrenal masses. We retrospectively reviewed 24 consecutive patients who underwent LA for large adrenal masses at a tertiary care university hospital. The average age of the 24 patients was 49 years, and each underwent laparoscopic resection of a large adrenal mass. All LAs were performed via a lateral transperitoneal approach. The average (+/- standard deviation) size of the masses was 6.8 +/- 1.5 cm (range, 5-11). Pathologic diagnoses included adrenal cortical adenoma (10 cases), pheochromocytoma ( 7), cyst/pseudocyst ( 3), myolipoma ( 2), and adrenal cortical hyperplasia ( 2). Statistical analysis was performed with a two-sample t test. The average operating time was 178 +/- 55 minutes (range, 120-300), and average blood loss was 87 +/- 69 mL (range, 20-300); the averages were nonsignificantly greater in the right LA group than in the left LA group (203 vs. 166 minutes, P = 0.89; 124 vs. 77 mL, P = 0.14). The average duration of nothing-by-mouth (NPO) status was 0.7 days (range, 0-4), and the average time until return to a regular diet was 1.74 +/- 0.9 days (range, 1-5). The average length of stay was 2.5 +/- 1.9 days (range, 1-10). One patient had a transient episode of pseudomembranous colitis. There were no conversions to open adrenalectomy and no major morbidities or mortalities. LA is safe and effective for surgical treatment of large adrenal masses. Both right and left large adrenal masses can be approached laparoscopically with equal success. The role of minimally invasive approaches to adrenal malignancies necessitates further investigation.     

Clinically inapparent bilateral adrenal masses due to histoplasmosis

Detection of bilateral adrenal masses in any patient often presents a management dilemma. Despite extensive imaging, positron emission tomography (PET) scanning, and fine needle aspiration biopsy (FNAB), a definite diagnosis may not be reached. We report an unusual case of bilateral adrenal mass diagnosed as histoplasmosis postoperatively and managed successfully by laparoscopy. Focus is placed on the role of laparoscopic adrenalectomy (LA) as a diagnostic and therapeutic tool in such patients.     

Radiologic characterization of adrenal masses: the role of computed tomography--derived attenuation values.

BACKGROUND: Recent studies suggest that low computed tomography (CT) attenuation values can be used to differentiate benign adrenal adenomas from non-adenomas. We examined the utility of non-enhanced CT attenuation values of 相似文献   

Management of incidentally discovered adrenal masses and risk of malignancy

BACKGROUND: Incidentally discovered adrenal masses of more than 1 cm in size are relatively frequent, but the correct management of such lesions is not well established. METHODS: Between 1980 and 1999, 158 patients (73 men [46.2%] and 85 women [53.8%]; median age, 58 years) with adrenal incidentalomas of more than 2 cm in size were observed. Sixty-eight patients (43.0%) underwent adrenalectomy. The main reasons for surgery were (1) suspicious computed tomography (CT) scan or magnetic resonance imaging (MRI) appearance or no uptake at the 75-Se-norcholesterol scintigraphy (NCS; n = 22 patients), (2) an increase in the size of the mass of more than l cm (n = 15 patients), (3) subclinical endocrine hyperfunction (n = 14 patients), and (4) mass size of more than 5 cm (n = 22 patients), with imaging-guided fine-needle aspiration biopsy with spinal-type narrow-gauge needle (FNAB) that suggested malignancy (n = 5 patients). RESULTS: Pathologic examination showed 39 adrenocortical adenomas (57.4%), 20 adrenal malignancies (29.4%; carcinomas, 15; unsuspected metastases, 3; nonfunctioning malignant pheochromocytomas, 2), and 9 various benign lesions (13.2%). All masses that increased in size were benign. Seven malignant tumors (46.7%) were 3 to 4 cm in size, and 14 benign lesions (29.1%) were 5 to 6 cm in size. Sensitivity and specificity in the detection of malignancy were 100% and 100% for NCS (n = 34 patients) and FNAB (n = 19 patients), 75.0% and 93.7% for CT scan (n = 68 patients), and 87.5% and 100% for MRI (n = 26 patients), respectively. CONCLUSIONS: To differentiate benign and malignant incidentalomas, NCS and FNAB are more sensitive than CT scan and MRI; size criteria are of little value.     

Adrenal masses: the investigation and management of adrenal incidentalomas

Most general surgeons will face at sometime in their career an ''incidentaloma'' of the adrenal gland. How should a surgeon approach an incidentaloma found during routine investigation for other unrelated disease processes? This paper discusses the investigation and management of adrenal incidentalomas and includes guidelines for the non-specialist.     

Serendipitous adrenal masses: prevalence, significance, and management

Over a 2 year period, 63 of 1,459 patients examined by computerized tomography were found to have adrenal masses. In 19 patients (1.3 percent of patients examined and 30 percent of patients with adrenal masses), they were unexpected and did not give rise to symptoms or signs. Three patients were explored. Two of the patients had adrenocortical adenomas and a third, a ganglioneuroma. Adrenal function tests were performed in 14 patients and showed evidence of Cushing's syndrome in 1 patients and revealed no abnormalities in 13. The lesions in 10 of 11 nonsurgical patients followed by computerized tomography for 11 to 36 months showed no change. One lesion became significantly smaller. In a review of 988 autopsy reports, grossly visible adrenal masses were present in 73 patients (7.3 percent), including 19 adrenocortical adenomas (1.9 percent) and 50 metastases (5 percent). We conclude that serendipitous adrenal masses are usually small, nonfunctioning, and benign, the most common lesion being adrenocortical adenoma. A protocol has been suggested for management to identify the minority of patients with functioning or malignant lesions and to avoid unnecessary surgery in the others who have benign disease.     

Evaluation and surgical resection of adrenal masses in patients with a history of extra-adrenal malignancy.

BACKGROUND: Adrenal abnormalities are often identified on imaging studies performed during the staging of patients presenting with a new malignancy or restaging of patients with a history of a malignancy. METHODS: We reviewed the records of patients who underwent surgical resection of an adrenal mass identified in the setting of previously or newly diagnosed extra-adrenal malignancy. RESULTS: Eighty-one patients with an adrenal mass and recently diagnosed malignancy (n = 24) or history of a malignancy (n = 57) underwent adrenalectomy. In 42 patients (52%) the adrenal mass was a metastasis. In 39 patients (48%) the adrenal mass was an additional primary adrenal tumor process: 19 pheochromocytomas, (14 syndrome-associated, 5 sporadic), 13 cortical adenomas, 3 adrenocortical carcinomas, 2 ganglioneuromas, and 2 cases of nodular hyperplasia. CONCLUSIONS: In this series nearly half of the patients with cancer and an adrenal mass had adrenal pathologic condition independent of their primary malignancy. Despite the presence of a newly diagnosed malignancy or history of malignancy, all patients with an adrenal mass should undergo a standard hormone evaluation to confirm that the mass is not a functional neoplasm. An assumption that the adrenal mass is metastatic disease will be wrong in up to 50% of such patients.     

Diagnosis and management of adrenal masses: 1987 Du Pont lecture

Adrenal enlargements were found in slightly more than 100 patients of approximately 15,000 who underwent abdominal computed tomography. A firm diagnosis was made in 61 patients. Of these, 34 were screened because of suspected metastases from nonadrenal tumours. Major causes of adrenal enlargement were metastases (20 patients), nonfunctioning adenomas (15) and hormonally active masses (9). Fine-needle aspiration biopsy was a useful diagnostic aid in patients with metastases. Surgical treatment was undertaken in 17 patients (three pheochromocytomas, one Cushing's adenoma, three Conn's adenomas, four primary carcinomas, two metastatic carcinomas, three nodular hyperplasias suspected to be part of the multiple endocrine adenopathy syndrome and one myelolipoma). Work-up of an adrenal mass includes a full history and physical examination, search for possible nonadrenal primary malignant lesions, testing for excess adrenal hormone secretion, computed tomography of the abdomen and fine-needle aspiration biopsy in selected patients.     

Ultrasonic,angiographic, and pathologic correlation of noncystic-appearing renal masses

The ultrasonic echo pattern of renal masses is retrospectively correlated with the angiographic vascular pattern in 36 cases where a noncystic-appearing mass was identified by either study. Pathologic or cytologic correlation was available in 31 of these masses. In carcinomas the echogenicity was usually found to correlate well with the degree of neovascularity.