Visualization of Adrenocortical Carcinoma Lung Metastases with lodine-131 Labeled 6B-iodomethylnorcholesterol (NP-59)
CATHERINE K. CHOW, M.D.,* HARVEY A. ZIESSMAN, M.D.,* AND JERRY M. EARLL, M.D.t
This case report describes visualization of lung metas- tases secondary to adrenocortical carcinoma using I- 131 labeled 6B-iodomethyl-19-norcholesterol (NP-59) in a 26-year-old woman with a recurrence of Cushing’s syndrome one year following surgical removal of the primary tumor.
From the Division of Nuclear Medicine, Department of Radiology,” and the Division of Medicine, Department of Internal Medicine, t Georgetown University Hospital, Washington, D.C.
A DRENAL GLAND UPTAKE of radiocholesterol has allowed the study and differentiation of various etiologies for zona fasciculata hyperfunction, i.e., Cushing’s syndrome. The pattern of I-131 labeled 19- iodocholesterol uptake has been shown to be highly accurate for differentiating bilateral adrenal hyperpla- sia from adrenal adenoma. However, with two excep- tions (1,2), visualization of adrenocortical carcinoma or its metastases with I-131 iodocholesterol has not been successful. Since the development of I-131 la- beled 6B-iodomethylnorcholesterol (NP-59), an analog of iodocholesterol, there have been several reports of visualization of metastases from adrenocortical carci- noma, presumably due to its higher adrenal tissue up- take compared to the earlier analog (3-5). This report describes visualization of lung metastases with NP-59 following resection of the primary tumor.
Case Report
A 26-year-old female enjoyed good health until the spring of 1984, when she noted increasing facial and labial hair, a progressive acneiform rash, fatty tissue redistribution, and a weight gain of 38 pounds in six months. By August 1984, she had also noted easy
bruisability, depression, and amenorrhea. Workup at that time showed elevated serum cortisol nonsuppres- sible with dexamethasone, high DHEA, testosterone, and free testosterone levels. An abdominal CT scan revealed a large right adrenal mass. In October 1984 she underwent a right adrenalectomy with removal of a 10 x 12 cm adrenal mass. The tumor was adherent to the underside of the liver, but was felt to be completely resected. Pathologically, the tumor exhibited grade III out of IV malignancy. The patient was placed on main- tenance corticosteroids postoperatively, and received radiotherapy with 4500 rads to the right renal bed.
The patient did well until January 1985 when she was readmitted to the hospital for right upper quadrant pain. A repeat abdominal CT scan at that time showed no evidence for recurrence of disease. She was dis- charged after spontaneous resolution of her symp- toms. By the spring of 1985, she appeared to have adequate adrenal function without the need for re- placement therapy, raising the possibility of recurrent disease or recovery of the remaining adrenal gland. There was elevation of plasma free cortisol and 24- hour urinary 17-hydroxy-corticosteroid levels despite low and high dose dexamethasone suppression. A 24- hour urinary testosterone level was also elevated at 40 mcg (normal = < 30). A repeat abdominal CT scan revealed no evidence of recurrence. Whole body scin- tigraphy with 1 mCi of NP-59 showed a large area of focal increased uptake in the right upper lung field (Fig. 1). Thereafter, a standard chest x-ray (Fig. 2) and a CT scan of the thorax confirmed a new 5.5 x 7 cm mass in the right upper lobe. A CT scan of the chest
Received for publication July 3, 1986; revision accepted Septem- ber 11, 1986.
Reprint requests: Harvey A. Ziessman, M.D., Division of Nu- clear Medicine, Georgetown University Hospital, 3800 Reservoir Road, NW, Washington, D.C. 20007.
showed several small 1 cm nodules in the right lower lobe. The chest x-ray of eight months earlier was normal.
Discussion
Adrenocortical carcinomas are rare tumors with a variable degree of function. The functional tumors (50-95%) can cause progressive Cushing’s syndrome and/or virilization. The remainder of the adrenal carci- nomas are endocrinologically silent and are presumed to be nonfunctional or to secrete inactive steroid pre- cursors. Metastases are most common in the para- aortic lymph nodes, lungs, liver, peritoneum, bone, and opposite adrenal gland.
Although many adrenocortical carcinomas produce excess cortisol, the percent uptake of radiolabeled cholesterol per gram of tissue is lower than that of normal tissue (6). This, together with suppression of the contralateral adrenal by hypercortisolism, results in the typical finding of bilateral nonvisualization on
scintigraphy. In contrast, adrenal hyperplasia or ad- enomas are successfully visualized with I-131 labeled 19-iodocholesterol, with the former showing intense bilateral adrenal visualization, and the latter suppres- sion of the contralateral normal adrenal (6). Neverthe- less, there have been two reports in the literature of I-131 19-iodocholesterol uptake by tumor metastases in the liver postadrenalectomy (1,2). In the mid 1970s, I-131 6B-iodomethyl-19-norcholesterol (NP-59) was developed because of its superior concentration in adrenal tissue (7). Seabold et al were able to measure higher levels of NP-59 in the metastases than pre- viously reported for I-131 19-iodocholesterol (3).
Using NP-59, Watanabe et al demonstrated uptake by hepatic metastases of adrenocortical carcinomas which was more intense than that of normal tissue (4). Seabold et al reported five cases of visualized metasta- ses from adrenocortical carcinoma in patients post- adrenalectomy (3). In their series, three out of four hepatic metastases were demonstrated by NP-59 up- take and several skeletal lesions were visualized by NP-59, although Tc-99m pyrophosphate was more sensitive. Of two lung metastases, only one was visu- alized with NP-59. Drane et al reported simultaneous visualization of both the primary adrenal tumor as well as a metastatic bone focus with NP-59 (5).
The present case demonstrates only the second re- ported instance of visualization of lung metastases sec- ondary to adrenocortical carcinoma with NP-59. NP- 59 scintigraphy is a noninvasive, effective means of
surveying the entire patient when recurrence is sus- pected, whether the primary cancer is functional or nonfunctional. Once the lesion is identified, other imaging procedures, such as CT scanning, can be directed towards the area of interest for better ana- tomic localization. Further study, however, is needed to determine the overall sensitivity and specificity of NP-59 for detecting primary and metastatic adrenocor- tical carcinoma.
References
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