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Magnetic resonance imaging of adrenal cortical carcinoma

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Page 1: Magnetic resonance imaging of adrenal cortical carcinoma

Urol Radiol 11:1-6 (1989) Urologic Radiology

© Springer-Verlag New York Inc. 1989

Magnetic Resonance Imaging of Adrenal Cortical Carcinoma

Stephen M. Smith, Suresh K. Patel, David A. Turner, and Terence A. S. Matalon Department of Diagnostic Radiology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois, USA

Abstract. Five cases of adrenal cortical carcinoma examined with magnetic resonance (MR) are pre- sented. Clinical histories, computed tomographic (CT) scans, and final pathologic findings were re- viewed in each case. All masses were hypointense compared to the liver on T,-weighted images and became hyperintense compared to the liver on T2- weighted images. Signal intensity of adrenal masses, fat, and liver were measured. Adrenal/liver and ad- renal/fat signal intensity ratios were then calculated. All the masses were readily identified with MR. The MR also demonstrated displacement or invasion of adjacent organs, as well as liver metastases. The inferior vena cava was also identified in each case.

Even though there were no consistent MR find- ings to diagnose adrenal cortical carcinomas accu- rately, superior blood vessel identification and mul- tiplanar capabilities may make MR the imaging modality of choice in evaluating the extent of disease and in planning surgical excision.

Key words: Magnetic resonance, adrenal -- Ad- renal cortical carcinoma -- Computed tomography, adrenal.

Recent reports have demonstrated the efficacy of magnetic resonance (MR) and computed tomogra- phy (CT) in detecting adrenal masses [ 1-7]. The MR technique has been suggested to have a potential

Address reprint requests to: Suresh K. Patel, M.D., Rush-Pres- byterian-St. Luke's Medical Center, Department of Diagnostic Radiology, 1653 West Congress Parkway, Chicago, IL 60612, USA

advantage over CT in categorizing adrenal masses, based upon signal intensity that varies with tissue type [ 1-3 ].

We present 5 cases of adrenal cortical carcinoma evaluated by MR. The clinical records, CT scans, and final pathologic findings were reviewed in each case .

Materials and Methods

Magnetic resonance examination of 5 patients with adrenal car- cinoma was performed from April, 1985, to October, 1987. All patients had previously undergone CT scans. The diagnosis in all cases was proven after surgical excision of the carcinoma.

Patients ranged in age from 23 to 62 years with a mean age of 50 years. Four of the 5 patients were women. Three patients presented with clinical symptoms consistent with Cushing's syn- drome. All 3 had elevated serum cortisol levels. Another patient had symptoms of hyperaldosteronism with increased serum al- dosterone levels. The fifth patient complained of vague abdom- inal pain and was found to have hypertension and normal lab- oratory values.

All patients underwent exploratory laparotomies with re- section of the adrenal masses. Ipsilateral nephrectomies were performed in 3 patients.

Resection of the right hepatic lobe, caudate lobe, gallblad- der, and the retrohepatic inferior vena cava was necessary in 1 patient with extensive right-sided tumor. A splencctomy and resection of the tail of the pancreas were performed in 1 patient with a large left-sided mass.

The MR examinations of all 5 patients were obtained on a 0.5 T superconducting magnet (Technicare, Inc., Solon, OH). Examinations were performed with a radio frequency (RF) coil with an aperture of 55 cm. Spin-echo images were obtained with relative T~ weighting (TE = 30-32 msec, TR = 530 msec) and T~ weighting (TE = 90-120 msec, TR = 2000-2300 msec). Trans- axial and coronal images were obtained in all cases. Sagittal im- ages were obtained for 1 of the 5 patients.

Relative signal intensities of liver, fat, and adrenal masses were evaluated subjectively. Signal intensities of liver, fat, and adrenal lesions on relative T2-weighted images were also mea- sured with a manually controlled region of interest, the area of

Page 2: Magnetic resonance imaging of adrenal cortical carcinoma

2 S.M. Smith et al.: MRI of Adrenal Carcinoma

Fig. 1. Common MR appearance of adrenal cortical carcinoma. A Tt-weighted image (TE/TR = 21/500) of right adrenal cortical carcinoma (arrows) with lower signal than liver. B T2-weighted image (TE/TR = 100/2300) demonstrates higher signal of adrenal mass (arrows) compared to liver.

Table 1. Radiologic findings in 5 cases of adrenal cortical carcinoma

IVC invasion/ Local invasion Metastasis displacement

Loca- Pt. Symptoms Size tion CT MR CT MR CT MR

A.B. Cushing's 12 cm L e f t None None Adenopathy Adenopathy No D.P. Cushing's 5 cm Right None None Liver Liver No F.J. Cushing's 9 cm L e f t None None None None No L.V. Hyperal- 13 cm Right Liver displace- Liver displace- None None Not visu-

dosteron- ment and/or ment with- alized ism invasion out invasion

L.B. Hyperten- l 3 cm Right Liver and right Liver and right None None Not visu- sion, pain kidney kidney alized

No No No Displaced

Obstructed

which included at least 11 pixels. Adrenal/liver and adrenal/fat signal intensity ratios were then calculated.

Results

All o f the adrenal tumors were large masses, ranging from 5 to 13 cm in diameter (Table 1). Three o f these masses originated from the right adrenal gland while the other 2 arose from the left.

On the T~-weighted M R images, all of the ad- renal tumors were subjectively and objectively hy- pointense with respect to the liver (Fig. 1A). The signal intensity o f the tumors in all 5 patients in- creased on TE-weighted images, becoming higher than liver parenchyma (Fig. 1 B). Adrenal/l iver and adrenal/fat signal intensity ratios were calculated on relative TE-weighted images on 4 o f 5 patients. Sig- nal intensity ratios were not calculated at identical

TE and TR for all patients. The mean adrenal/liver ratio was 2.0 with a range o f 1.6-2.4 and an SD of 0.1. Mean adrenal/fat ratio was 1.0 with a range o f 0.77-1.2 and an SD of 0.25.

Patency, or lack thereof, o f the inferior vena cava (IVC) was discernible on each examination. The IVC was patent throughout its entirety on 4 o f the 5 M R scans. In 1 patient the IVC was displaced by a large right-sided mass (Fig. 2). Obstruction o f the IVC was demonstrated in another patient from the level of the left renal hilum to just caudal to the right atrium. In addition, multiple paravertebral collaterals were present along with the dilated azy- gous vein. These findings correlated well with an inferior vena cavogram (Fig. 3).

Direct invasion of both the right and left lobes o f the liver was seen in 1 patient with a right-sided tumor. One patient with a left-sided tumor had he-

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S.M. Smith et al.: MRI of Adrenal Carcinoma 3

Fig. 2. Displacement oflVC. A Tt-weighted sagittal (TE/TR = 30/530) image of large right adrenal conical carcinoma (large arrows) with anterior displacement and compression of inferior vena cava (small arrows). Collaterals were better demonstrated on transaxial images. B Cavogram confirms anterior displacement of the inferior vena cava (large arrows) with multiple collaterals (small arrows).

patic lesions suggestive of metastases, which, at sur- gery, proved to be bile duct hamartomas. Another patient with a right-sided tumor had multiple me- tastases demonstrated on MR, with additional liver lesions discovered during intraoperative sonogra- phy. Differentiation between the primary adrenal neoplasm and a renal neoplasm, which was not clear on CT, was more readily accomplished on coronal and transaxial MR in 1 patient when the epicenter of the mass was demonstrated to be in the expected location of the fight adrenal gland (Fig. 4).

Discussion

Adrenal cortical carcinoma is a rare tumor, account- ing for less than 0.2% of all cancer deaths, with an incidence of approximately 2 cases per million peo- ple. 8 It occurs in all decades of life, with a median age of 40 years and slight male predominance. Com- mon presentations include pain, abdominal mass, and endocrinopathy. Steroid production occurs in more than 50% of cases, accounting for clinical man- ifestations such as feminization in males, viriliza- tion in females, Cushing's syndrome, and hyperten- sion.

At presentation these tumors are usually large and may displace or compress adjacent organs. Ex- tension into the IVC can occur. Involvement may be bilateral. Common sites of metastases include regional and paraaortic lymph nodes, the lungs, and liver. Due to their large size, adrenal cortical car- cinomas may outgrow their blood supply, leading to areas of necrosis. Dystrophic calcification may also be seen.

The prognosis is poor, with histopathologic findings and staging being important prognostic in- dicators [9, 10]. Surgery remains the only cure, and radical en bloc excisions are often necessary.

The CT scan is highly sensitive in detecting ad- renal masses, yet differentiation between benign and malignant adrenal tumors has not been possible with CT. Features such as size, consistency, and contrast enhancement have been reported to be significant by various authors [5]. Unfortunately, other authors have not found these to be as reliable [6].

Magnetic resonance has been shown to be effi- cacious in detecting adrenal masses [4, 7]. Recent reports have also suggested that MR can differen- tiate benign and malignant masses on the basis of their signal intensities [1--4]. By measuring the ad-

Page 4: Magnetic resonance imaging of adrenal cortical carcinoma

4 S.M. Smith et at.: MRI of Adrenal Carcinoma

~ I F e" . ,a~, ~

Fig. 3. Obstruction of IVC. A T2-weighted sagittal scan (100/2300) shows large paraver- tebral collateral vein (arrows) without demon- stration of a patent IVC more cephalad. B Cavo- gram identifies filling defect within IVC (arrowhead) along with large collaterals (ar- rows).

renal/liver signal intensity ratio on relative T 2- weighted images, Reinig et al. classified adrenal tu- mors into 3 groups: adenomas, which have a low signal intensity ratio (less than 1.2); metastases and carcinomas, with intensity ratios between 1.4 and 2.7; and pheochromocytomas, with a high signal intensity ratio (greater than 3.4). However, certain adenomas, metastases, and carcinomas (21% of their patients) made up a fourth "'nondiagnostic" group with signal intensity ratios in the 1.2-1.4 range. Chang et al. used adrenal/fat signal intensity ratios on T2-weighted images to differentiate adrenal masses [4]. All lesions with a ratio greater than 0.8 were malignant. Adenomas had ratios less than 0.6. However, 31% of the adrenal masses, which in- cluded 4 adenomas and 4 malignant neoplasms, had ratios in the 0.6-0.8 range.

All 5 patients we studied had large adrenal masses at presentation. The signal characteristics were similar, with lower signal intensity with respect to the liver on T~-weighted images and higher in- tensity on the T2-weighted images. Both the adrenal/ liver and adrenal/fat signal intensity ratios on T2- weighted images correlated well with previous re- ports [1, 4]. All the adrenal/liver ratios were greater than 1.4, whereas the adrenal/fat ratio in 1 patient was less than 0.8. None of the adrenal/liver ratios exceeded 3.4.

As previously stated, these parameters have been found useful in differentiating adrenal masses. Our data suggest that the adrenal/liver signal intensity ratio may have greater potential than adrenal/fat signal intensity ratio for tissue characterization. However, the use of signal intensity ratios for dif-

Page 5: Magnetic resonance imaging of adrenal cortical carcinoma

S.M. Smith et at.: MRI of Adrenal Carcinoma 5

Fig. 4. Multiplanar capabilities. A T~- weighted coronal scan (TE/TR = 30/530) demonstrates epicenter (arrows) of adrenal mass in expected location of right adrenal gland. B Right adrenal mass (arrows) on T~- weighted transaxial scan (TE/TR = 30/530).

ferentiating benign f rom malignant adrenal masses remains investigational [ 1 1 ].

All the masses were readily identified by both MR and CT. In 1 o f the patients, transaxial and coronal M R images more clearly demonst ra ted an abdominal mass as adrenal rather than renal in or- igin, which was questioned on a previous CT scan. Compression or displacement of adjacent organs was also well demonst ra ted by MR in each case. Inva- sion o f the liver by direct spread in 1 patient was discernible. The MR image also identified hepatic lesions in 2 patients. In 1 patient, the lesions proved to be bile duct hamartomas, while the other patient

had metastases with additional lesions discovered during intraoperat ive hepatic sonography.

The MR image identified the IVC in all patients, with obstruction in 1 patient and displacement in another. However, CT demonstrated the IVC in only 3 o f 5 cases. In 2 patients with large right-sided masses, CT failed to define clearly the IVC through- out its course.

The best therapy for adrenal cortical carcinoma remains en bloc resection. The mult iplanar capa- bilities o f MR along with its superior identification o f blood vessels and the possibility o f tissue char- acterization may enable MR to be the imaging pro-

Page 6: Magnetic resonance imaging of adrenal cortical carcinoma

cedure of choice in evaluating the extent of disease and planning surgical excision in patients with ad- renal cortical carcinoma.

References

1. Reinig JW, Doppman JL, Dwyer A J, Johnson AR, Knop RH: Adrenal masses differentiated by MR. Radiology 158: 81-84, 1986

2. Glazer GM, Woolsey EJ, Borrello J, et at: Adrenal tissue characterization using MR imaging. Radiology 158:73-79, 1986

3. Reinig JW, Doppman JL, Dwyer AJ, Frank J: MRI of in- determinate adrenal masses. A JR 147:493-496, 1986

4. Chang A, Glazer HS, Lee JKT, Ling D, Heiken JP: Adrenal gland: MR imaging. Radiology 163:123-128, 1987

5. Hussain S, Belldegrun A, Seltzer SE, Richie JP, Gittes RF,

S.M. Smith et at.: MRI of Adrenal Carcinoma

Abrams HL: Differentiation of malignant from benign ad- renal masses. A JR 144:61-65, 1985

6. Fishman EK, Deutch BM, Hartman DS, Goldman SM, Zer- houini EA, Siegelman SS: Primary adrenocortical carci- noma: CT evaluation with clinical correlation. A JR 148:531- 535, 1987

7. Falke THM, te Strake L, Sandier MP, et al: Magnetic reso- nance imaging of the adrenal glands. Radiographics 7:343- 370, 1987

8. Lipsett MB, Hertz R, Ross GT: Clinical and pathophysio- logical aspects of adrenocortical carcinoma. Am J Med 35: 374-383, 1963

9. Bradley EL III: Primary and adjunctive therapy in carcinoma of the adrenal cortex. Surg Gynecol Obstet 141:507-511, 1975

10. Sullivan M, Boileau M, Hodges CV: Adrenal cortical car- cinoma. J Urol 120:660--665, 1978

11. Glazer GM: MR imaging of the liver, kidneys and adrenal glands. Radiology 166:303-312, 1988