Functional imaging of adrenal cortex. / Estudios de imagen funcional de la corteza adrenal.

The rising number of high-resolution imaging scans has increased the adrenal lesions detection, which require a differential diagnosis. Currently, the most commonly used scans are CT and MRI, but these are sometimes not very specific. In these cases, nuclear medicine scans with 131I-norcolesterol, 11C-metomidate and 18F-fludeoxyglucose help to differentiate benign vs. malignant lesions, to lateralize the involvement in hypersecretion disease, as well as to guide the therapeutic strategy in both unilateral and bilateral lesions.

131I-6ß-iodomethyl-19-norcholesterol adrenal scintigraphy as an alternative to adrenal venous sampling in differentiating aldosterone-producing adenoma from bilateral idiopathic hyperaldosteronism.

OBJECTIVE: To assess the correlation value between adrenal venous sampling (AVS) and I-6ß-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy in differentiating aldosterone-producing adenoma (APA) from bilateral idiopathic hyperaldosteronism (BHA), and the use of NP-59 scintigraphy as an alternative to AVS. METHODS: Overall, 29 patients with APA or BHA who underwent AVS and dexamethasone-suppression NP-59 scintigraphy were included between 2010 and 2017. The correlation value between AVS and dexamethasone-suppression NP-59 scintigraphy was assessed using each lateralisation index (LIAVS and LI1NP-59). Tumour presence and size were evaluated using computed tomography. The sensitivity and specificity of dexamethasone-suppression NP-59 scintigraphy for APA according to each lateralisation index threshold were calculated. RESULTS: Of 29 patients, 12 presented with APA and 17 with BHA according to AVS. The correlation value between LIAVS and LI1NP-59 was 0.63 (P < 0.001). If the cut-off points were 2.55 and 1.80 in all cases, the sensitivity and specificity were 0.33 and 1.00 as well as 0.58 and 0.94, respectively. In adrenal microtumours (maximum diameter ≤10 mm), no cases revealed a cut-off point of >1.8. However, in adrenal macrotumours (maximum diameter >10 mm), the cut-off point of 2.55 represented the best compromise (sensitivity: 0.44; specificity: 1.00). CONCLUSION: NP-59 scintigraphy can be used as an alternative to AVS if there is a strong lateralisation on NP-59 scintigraphy and adrenal macrotumours observed on the computed tomography when AVS is technically challenging, particularly in the right adrenal vein cannulation, and if contraindications, such as allergy to contrast materials and renal failure, are observed.

The value of 18F-FDG PET-CT and 131I-norcholesterol scintigraphy in the characterization of high-risk adrenal masses.

PURPOSE: To assess the value of F-FDG PET-computed tomography (CT) and I-norcholesterol scintigraphy in noninvasive characterization of high-risk adrenal lesions using surgical pathology as the gold standard. METHODS: We retrospectively reviewed clinical cases referred to the adrenal multidisciplinary team in a tertiary centre over the last 6 years. Inclusion criteria were the presence of indeterminate adrenal lesions and performance of combined imaging with 2-deoxy-2-[fluorine-18] fluoro- D-glucose Positron emission tomography/ computed tomography and I-norcholesterol scans. The accuracy of CT, PET-CT and I-norcholesterol findings was assessed by comparison with the postoperative histopathological outcome. RESULTS: Sixteen patients fulfilled the inclusion criteria. Ten underwent unilateral adrenalectomy, and six had clinical follow-up. The number of cases categorized as concerning on the basis of unenhanced CT, F-FDG PET-CT and I-norcholesterol was 11, 9 and 2, respectively. The mean diameter of adrenal lesions was 4.5 ± 1.9 cm. Average SUVmax of the FDG-avid adrenal lesions was 5.0 ± 2.0 (range 3.5-9.7). Fourteen adrenal masses showed I-norcholesterol uptake. All adrenal masses turned out to be benign lesions. CONCLUSION: Conventional CT and FDG PET parameters are not adequately specific for determination of a benign lesion in this selected cohort of high-risk patients. Use of I-norcholesterol in this patient cohort may provide additional value.

Diagnostic value of adrenal iodine-131 6-beta-iodomethyl-19-norcholesterol scintigraphy for primary aldosteronism: a retrospective study at a medical center in North Taiwan.

BACKGROUND: Primary aldosteronism (PA) is a common cause of secondary hypertension. Among the many leading causes of PA, the two most frequent are, bilateral adrenal hyperplasia (BAH) and aldosterone-producing adenomas (APA). Since a solitary APA may be cured surgically, but BAH needs lifelong pharmacologic therapy, confirmation is mandatory before surgery. We herein sought to determine the diagnostic value of iodine-131 6-beta-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy to distinguish BAH from APA. PATIENTS AND METHODS: Patients clinically suspected of PA from March 2000 to October 2016 were retrospectively analyzed. A total of 145 patients, including 74 postunilateral adrenalectomy and seven postradiofrequency ablation for adrenal mass, were reviewed. All patients received NP-59 adrenal scintigraphy prior to surgery. The accuracy of the NP-59 adrenal scintigraphy was confirmed by the pathologic findings and postoperative outcomes. RESULTS: Among 81 patients receiving interventional procedures for adrenal mass, adenoma was eventually diagnosed in 72 patients according to their pathologic results, with 60 unilaterally and seven bilaterally localized lesions by NP-59 scintigraphy; nevertheless, there were five negative findings initially. The sensitivity, specificity, and positive predictive value of NP-59 scintigraphy for APA detection were therefore 83.3, 44.4, and 92.3%, respectively. Moreover, single-photon emission computed tomography/computed tomography scan increased the sensitivity and specificity, but not the positive predictive value (85.0, 60.0, and 89.5%) of NP-59 scintigraphy in this study. CONCLUSION: NP-59 adrenal scintigraphy is a useful imaging test to detect APA. Lateralization by this modality prior to surgical intervention may reduce the need for such invasive procedures as adrenal venous sampling.

Contralateral adrenal suppression on adrenocortical scintigraphy provides good evidence showing subclinical cortisol overproduction from unilateral adenomas.

Unilateral and/or predominant uptake on adrenocortical scintigraphy (ACS) may be related to autonomous cortisol overproduction in patients with subclinical Cushing's syndrome (SCS). However, there is no information regarding whether increased tracer uptake on the tumor side or decreased uptake on the contralateral side on ACS is more greatly associated with inappropriate cortisol production. Therefore, we evaluated the relationship between quantitative 131I-6ß-iodomethyl-norcholesterol (131I-NP-59) uptake in both adrenal glands and parameters of autonomic cortisol secretion and attempted to set a cut off for SCS detection. The study included 90 patients with unilateral adrenal adenoma who fulfilled strict criteria. The diagnosis of SCS was based on serum cortisol ≥3.0 µg/dL after 1-mg dexamethasone suppression test (DST) with at least 1 other hypothalamus-pituitary-adrenal axis function abnormality. Twenty-two (27.7%) subjects were diagnosed with SCS. The uptake rate on the affected side in the SCS group was comparable to that in the non-functioning adenoma group. In contrast, the uptake rate on the contralateral side was lower and the laterality ratio significantly higher in the SCS group. The two ACS indices were correlated with serum cortisol levels after a 1-mg DST, but uptake on the tumor side was not. Tumor size was also important for the functional statuses of adrenal tumors and NP-59 imaging patterns. The best cut-off point for the laterality ratio to detect SCS was 3.07. These results clearly indicate that contralateral adrenal suppression in ACS is good evidence showing subclinical cortisol overproduction.

The role of adrenal scintigraphy in the diagnosis of subclinical Cushing's syndrome and the prediction of post-surgical hypoadrenalism.

BACKGROUND: Management of subclinical Cushing's syndrome (SCS) remains controversial; it is not possible to predict which patients would benefit from adrenalectomy. In the present study we aimed to evaluate the role of adrenocortical scintigraphy (ACS) in the management of patients with SCS. METHODS: The medical records of 33 consecutive patients with adrenal "incidentaloma" and proven or suspected SCS who underwent (131)I-19-iodocholesterol ACS between 2004 and 2010 were reviewed. Sixteen underwent laparoscopic adrenalectomy (surgical group-S-group) and 17 were medically managed (medical group-M-group). Follow-up evaluation was obtained by outpatient consultation. RESULTS: Overall 25 patients (15 in the S-group and 10 in the M-group) had concordant unilateral uptake at ACS (ACS+). In the S-group, the mean follow-up duration was 30.9 ± 16.1 months and, irrespective of the presence of hormonal diagnosis of SCS, in patients who were ACS+ adrenalectomy resulted in a significant increase in HDL cholesterol and decreases in body mass index, glycemia, and blood pressure (BP). One patient reduced antihypertensive medication and three others were able to discontinue it altogether. Prolonged postoperative hypoadrenalism (PH) occurred in 14 patients in the S-group. The overall accuracy in predicting PH was 93.7 % for ACS and 68.7 % for laboratory findings. In the M-group, the mean follow-up duration was 31.5 ± 26.3 months and no patient developed overt Cushing's syndrome, although ACS+ patients experienced a worsening in glycemia and diastolic BP. CONCLUSIONS: Adrenal scintigraphy seems the most accurate diagnostic test for SCS. It is able to predict the metabolic outcome and the occurrence of PH, identifying the patients who could benefit from adrenalectomy irrespective of hormonal diagnosis.

Quantitative imaging characterization of hypersecreting or nonhypersecreting adrenal adenomas: comparison between iodine-131 norcholesterol uptake and magnetic resonance signal intensity ratios.

OBJECTIVE: To compare norcholesterol uptake and magnetic resonance (MR) signal intensity ratios (SIRs) in characterizing adrenal adenomas to differentiate hypersecreting from nonhypersecreting lesions. METHODS: We studied 34 patients (14 males and 20 females, mean age: 47±15 years) with hypersecreting (n=19) or nonhypersecreting (n=15) adrenal adenomas; all patients underwent iodine-131 norcholesterol scintigraphy and MR studies. Pathology (n=26) or follow-up data (n=8) were obtained. Imaging studies were qualitatively evaluated to calculate diagnostic accuracy of each test; radionuclide studies were also semiquantitatively evaluated using a four-point score to measure norcholesterol uptake, whereas MR scans were quantitatively assessed for measuring SIRs of adrenal lesions. Imaging data were then compared between hypersecreting and nonhypersecreting adenomas. RESULTS: The diagnostic accuracies of norcholesterol (100%) and MR (95%) scans to identify adrenal adenomas were similar; however, while a significantly (P=0.01) higher norcholesterol uptake was observed in hypersecreting (2.8±0.5 cm) adenomas compared with nonhypersecreting (2.28±0.6 cm) lesions, no significant differences in SIRs were found in this comparative analysis; in this regard, no significant difference in tumor size (centimeter) occurred between hypersecreting (2.7±0.5 cm) and nonhypersecreting (3.1±0.9 cm) adenomas. CONCLUSION: Adrenal scintigraphy using norcholesterol and MR are both able to accurately identify cortical adenomas; however, while semiquantitative analysis of norcholesterol uptake is effective to differentiate between hypersecreting and nonhypersecreting adenomas, SIRs evaluation is not useful for this purpose; in particular, the lower norcholesterol uptake observed in nonhypersecreting adenomas might reflect the normal hormone synthesis status of these lesions and, thus, regular secretion; this finding could also reflect initial adrenal dysfunction responsible for subclinical disorders.

Adrenal cortical imaging with I-131 NP-59 SPECT-CT.

PURPOSE: The purpose of this article is to present our initial experience with hypersecretory adrenal syndromes investigated with radioiodinated I-6-B-iodomethyl-19-norcholesterol (NP-59) and SPECT-CT. MATERIALS AND METHODS: Illustrative cases are presented of patients being investigated for adrenal hypersecretory syndromes, with or without adrenal nodules, using NP-59 scintigraphy with SPECT-CT imaging, representing a spectrum of diagnoses. Clinical and imaging data are reviewed to evaluate whether additional information derived from near-simultaneous anatomic localization aids study interpretation. RESULTS: The final diagnoses reached are hyperfunctional and nonfunctioning adrenal nodules, physiological bowel activity, and bilateral adrenal hyperplasia. SPECT-CT assisted study interpretation by localizing focal uptake to the adrenal glands, allowing direct assessment of function within adrenal nodules, and distinguishing physiological bowel activity from adrenal uptake. SPECT-CT provided additional information to planar and SPECT imaging, which improved confidence of study interpretation. CONCLUSION: Utilization of SPECT-CT with NP-59 scintigraphy allows precise localization of the functional activity to anatomic structures improving diagnostic interpretation.

131I-6beta-iodomethyl-19-norcholesterol SPECT/CT for primary aldosteronism patients with inconclusive adrenal venous sampling and CT results.

UNLABELLED: The 2 main causes of primary aldosteronism (PA) are aldosterone-producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH). Dexamethasone-suppression (131)I-6beta-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy can assess the functioning of the adrenal cortex. This study evaluated the diagnostic usefulness of NP-59 SPECT/CT in differentiating APA from IAH and in predicting postadrenalectomy clinical outcome for PA patients who had inconclusive adrenal venous sampling (AVS) and CT results. METHODS: We retrospectively reviewed the 31 adrenal lesions of 27 patients (age range, 33-71 y; mean age +/- SD, 50.4 +/- 10.9 y) who had been clinically confirmed (by saline infusion and captopril tests) to have PA, had inconclusive CT and AVS test results, and had undergone NP-59 imaging before adrenalectomy. The accuracy of NP-59 imaging was determined by comparison with histopathologic findings. RESULTS: NP-59 SPECT/CT gave us 18 true-positive, 3 false-positive, 6 true-negative, and 4 false-negative results. Compared with planar imaging, SPECT/CT significantly improved diagnostic accuracy and prognostic predicting ability (P = 0.0390 and P = 0.0141, respectively). The NP-59 results were negative for 7 of the 23 patients with unilateral adrenal lesions, and none of these 7 patients had shown postsurgical clinical improvement. CONCLUSION: NP-59 SPECT/CT is an effective imaging tool for differentiating APA from IAH in PA patients whose CT and AVS results are inconclusive. Our results suggest that patients with presurgically negative NP-59 results should be treated medically and that noninvasive NP-59 SPECT/CT may be suited for use as the first lateralization modality after CT in patients with clinically confirmed PA.

[Adrenal incidentaloma and nuclear medicine examination]. / Différentes explorations d'un incidentalome surrénalien en médecine nucléaire.

In the setting of adrenal incidentaloma, nuclear medicine evaluation is only indicated after biological and imaging work-up has been completed. MIBG scintigraphy is helpful to characterize pheochromocytomas. In lesions without MIBG uptake, 18F FDG or 18F DOPA PET can be considered to characterize chromaffin cell tumours. To characterize lesions of the adrenal cortex, iodocholesterol scintigraphy is performed to confirm the origin of the adenoma and the benign or malignant nature of the lesion since benign adenomas show tracer uptake and malignant lesions show no tracer uptake. 18F FDG PET only characterizes the lesion as benign or malignant.

Quantitative evaluation of norcholesterol scintigraphy, CT attenuation value, and chemical-shift MR imaging for characterizing adrenal adenomas.

OBJECTIVE: The objective of our study was to evaluate diagnostic ability and features of quantitative indices of three modalities: uptake rate on norcholesterol scintigraphy, computed tomography (CT) attenuation value, and fat suppression on chemical-shift magnetic resonance imaging (MRI) for characterizing adrenal adenomas. METHODS: Image findings of norcholesterol scintigraphy, CT, and MRI were reviewed for 78 patients with functioning (n = 48) or nonfunctioning (n = 30) adrenal masses. The norcholesterol uptake rate, attenuation value on unenhanced CT, and suppression on in-phase to opposed-phase MRI were measured for adrenal masses. RESULTS: The norcholesterol uptake rate, CT attenuation value, and MR suppression index showed the sensitivity of 60%, 82%, and 100%, respectively, for functioning adenomas of <2.0 cm, and 96%, 79%, and 67%, respectively, for those of >or=2.0 cm. A statistically significant correlation was observed between size and norcholesterol uptake, and between CT attenuation value and MR suppression index. Regarding norcholesterol uptake, the adenoma-to-contralateral gland ratio was significantly higher in cortisol releasing than in aldosterone-releasing adenomas. CONCLUSIONS: The norcholesterol uptake rate was reliable for characterization of adenomas among adrenal masses of >or=2.0 cm. CT attenuation value and MR suppression index were well correlated with each other, and were useful regardless of mass size.

Prevention of tumor recurrence and distant metastasis formation in a breast cancer mouse model by biodegradable implant of 131I-norcholesterol.

Brachytherapy has many potential roles in cancer therapy. However, major constraints are associated with placement and removal procedures of the brachytherapy machinery. An attractive approach would be the use of a biodegradable implant loaded with a radioisotope, thus enabling targeted radiotherapy, while reducing the need for surgical procedures for the removal of brachytherapy hardware. In this study, crosslinked chitosan (Ct) hydrogels were prepared and loaded with (131)I-norcholesterol ((131)I-NC). The radioactive hydrogels ((131)I-NC-Ct) were implanted adjacent to 4T1 cell-induced tumors in two different xenograft mice models either as primary therapy or surgical adjuvant therapy of breast cancer. Non-treated mice and mice implanted with naive (non-radioactive) hydrogels served as control groups. In the primary therapy model, the progression rate of the tumor was delayed by two weeks compared with the non-treated and the naive-implant control animals, resulting in a one-week extension in the survival of the treated animals. In the adjuvant therapy model, for the treatment of minimal residual disease, (131)I-NC-Ct implants were able to prevent 69% of tumor recurrence, and to prevent metastatic spread resulting in long-term survival, compared with 0% long-term survival of the non-treated and the naive control groups. Imaging of the hydrogel's in vivo elimination revealed a first order process with a half-life of 14 days. The degradation was caused by oxidation of the Ct as was assessed by in vitro H&E stain. Biodegradable radioactive implants are suggested as a novel platform for the delivery of brachytherapy. This radiotherapy regimen may prevent locoregional recurrence and metastatic spread after tumor resection.

High risk of malignancy in patients with incidentally discovered adrenal masses: accuracy of adrenal imaging and image-guided fine-needle aspiration cytology.

AIMS AND BACKGROUND: The incidental finding of nonfunctioning adrenal masses (incidentalomas) is common, but no reliable criteria in differentiating between benign and malignant adrenal masses have been defined. The aim of this preliminary study was to assess the usefulness of adrenal imaging and image-guided fine-needle aspiration cytology in patients with nonfunctioning adrenal incidentalomas with the aim of excluding or confirming malignancy before surgery. METHODS: Forty-two consecutive patients (18 men and 24 women; median age, 54 years; range, 25-75 years) with incidentally discovered adrenal masses of 3 cm or more in the greatest diameter were prospectively enrolled in the study. All patients underwent helical computerized tomography scan and image-guided fine-needle aspiration cytology, 33 (78.6%) underwent magnetic resonance imaging, and 26 (61.9%) underwent norcholesterol scintigraphy before adrenalectomy. RESULTS: The revised final pathology showed 30 (71.4%) benign (26 adrenocortical adenomas, of which 3 were atypical, 2 ganglioneuromas, and 2 nonfunctioning benign pheochromocytomas) and 12 (28.6%, 95% CI = 15-42) adrenal malignancies (8 adrenocortical carcinomas and 4 unsuspected adrenal metastases). The definitive diagnosis of adrenocortical carcinoma was made according to Weiss criteria and confirmed on the basis of local invasion at surgery or metastases. The sensitivity, specificity and accuracy were 75%, 67% and 83% for computerized tomography scan, 92%, 95% and 94% for magnetic resonance imaging, 89%, 94% and 92% for norcholesterol scintigraphy, and 92%, 100% and 98% for fine-needle aspiration cytology. The sensitivity and accuracy of image-guided fine-needle aspiration cytology and magnetic resonance imaging together reached 100%. Immediate periprocedural complications of fine-needle aspiration cytology occurred in 2 (4.7%) patients: self-limited pneumothorax (n = 1), and severe pain (n = 1) requiring analgesic therapy. No postprocedural or late complications were observed. CONCLUSIONS: With the aim of selecting for surgery patients with a non-functioning adrenal incidentaloma of 3 cm or more in diameter, the combination of magnetic resonance imaging and fine-needle aspiration cytology should be considered the strategy of choice.

Biocompatibility evaluation of crosslinked chitosan hydrogels after subcutaneous and intraperitoneal implantation in the rat.

The aim of the present study was to evaluate the toxicity of biodegradable hydrogels in the rat with a future aim of utilizing this hydrogel as a vehicle for brachytherapy delivery in cancer patients. Two types of chitosan hydrogels: fast degrading and slow degrading; were prepared and surgically implanted in rats. The adjacent tissue response to the gels after subcutaneous and intraperitoneal implantation was examined histologically and found to be identical to typical foreign body response and was milder than the response to absorbable surgical sutures (Vicril). Neither tissue damage nor gel fragments could be detected in distant organs (brain, heart, lungs, liver, spleen, kidney, and sternal bone marrow) after implantation of the hydrogels. The degradation mechanism of the gels was studied in vivo, and it was deduced that an oxidative process degraded the chitosan. Loading the hydrogels with a radioisotope (131I-norcholesterol) caused a severe tissue response and necrosis in adjacent tissues only at a distance of several microns. It is concluded that crosslinked chitosan implants could serve as alternative, biocompatible, and safe biodegradable devices for radioisotope delivery in brachytherapy for cancer.

A case of ganglioneuroma in which 131I-6beta-iodomethyl-19-norcholest-5(10)-en-3beta-ol scintigraphy showed high uptake in the adrenal gland leading to a misdiagnosis.

We experienced a case in which 131I-6beta-iodomethyl-19-norcholest-5(10)-en-3beta-ol (131I-adosterol) scintigraphy showed high uptake in the right adrenal gland. We diagnosed functional cortical adenoma because of the finding of 131I-adosterol scintigraphy. However, no positive findings for the existence of cortical adenoma were obtained in other examinations and we performed right adrenalectomy. Unexpectedly, pathological finding showed the right adrenal gland was occupied with a large ganglioneuroma. This is an instructive case in which 131I-adosterol scintigraphy showed abnormal high uptake in the adrenal gland, in spite of the fact that the adrenal gland was occupied by a tumor derived from adrenal medulla.

Crosslinked chitosan implants as potential degradable devices for brachytherapy: in vitro and in vivo analysis.

Compared with conventional external beam radiation, brachytherapy offers a superior therapeutic regimen. However, some major constraints are associated with its implementation, including the need of complicated procedures for device placement and removal. The purpose of this study was to examine whether crosslinked chitosan (Ct) implants could serve as potential biodegradable devices for brachytherapy. Ct was reacted with increasing amounts of glutaraldehyde to obtain hydrogels with different crosslinking densities, which were characterized chemically, thermally and mechanically. The effect of the dialysis medium conditions (ionic strength, osmolarity and pH) on the gel hydration and in vivo degradation was assessed. Two types of implants, slow and fast degrading gel (SDG and FDG, respectively), were prepared and implanted with or without Sudan Black (SB) in the rat. While SDG withstood for over a month, the FDG degraded within two weeks after implantation. The release kinetics of SB from the hydrogels verified their in vivo degradation properties. The incorporation of the radioactive compound (131)I-norcholesterol ((131)I-NC) into the SDG altered the degradation kinetics of the gel as reflected by the release kinetics of the radioactive marker. Eighty percent of (131)I-NC was released within a month after implantation, after which time, radioactivity was detected in the regional lymph nodes. Histological examination of the tissues surrounding the implants demonstrated negligible tissue response to the implants, when compared to biodegradable surgical sutures. It is concluded that hydrogels made of crosslinked Ct are potential novel, safe, degradable devices for brachytherapy.

Tomographic evaluation of [131I] 6beta-iodomethyl-norcholesterol standardised uptake trend in clinically silent monolateral and bilateral adrenocortical incidentalomas.

AIM: The aim of this study was three-fold: 1) to quantify [131I]-6beta-iodomethyl-norcholesterol ([131I]-NP-59) adrenal uptake trend in patients with incidentalomas, 2) to identify a specific uptake trend (TREND) capable of characterising pre-clinical Cushing syndrome (PC-CS) patients, 3) to assess the clinical availability of TREND as a prognostic factor of late clinical outcome in a cohort of patients with bilateral adrenal adenomas. METHODS: Fifty-seven consecutive patients were examined using three-head SPECT at 24, 48, 72 hours following intravenous injection of [131I ]-NP-59. On the basis of the absence or presence of hormonal abnormalities, the selected population was classified as GR1 or GR2, respectively. Adrenal glands were classified into 4 groups taking into account both the patient group (GR1, GR2) and the presence (+) or absence (-) of the adenoma (AD) on CT scan. Using ROI technique, adrenal-liver uptake ratio (A/L) was estimated bilaterally at 24, 48 and 72 hours. For each adrenal group, mean [131I]-NP-59 uptake trends were derived. RESULTS: TREND was significantly different between GR1/AD+ and GR2/AD+. Among GR2/AD+ patients, TREND correctly identified PC-CS with a global accuracy of 74%. Two patients with bilateral incidentaloma developed an overt CS. In both patients, TREND correctly identified the hyperfunctioning adrenal, thus permitting an effective sparing adrenalectomy. CONCLUSIONS: TREND seems to be a parameter which closely reflects adrenal physiological behaviour, especially in the case of bilateral adrenal involving. The possibility to quantify even contralateral adrenal uptake as standardised index provides additional useful information about normal adrenal parenchyma and, indirectly, about adenoma functional autonomy.

Collision/composite tumors of the adrenal gland: a pitfall of scintigraphy imaging and hormone assays in the detection of adrenal metastasis.

CONTEXT: In patients with a history of extraadrenal tumor, incidental discovery of an adrenal mass necessitates excluding the possibility of metastatic malignancy. Detection of the malignant tissue is a difficult challenge when metastasis occurs in an adrenal adenoma, forming a collision/composite tumor. OBJECTIVE, DESIGN, AND SETTING: We report two patients with adrenal collision/composite tumors referred to two French university hospitals. PATIENTS AND RESULTS: Two patients with histories of mammary and sigmoid carcinomas, respectively, presented with adrenal mass discovered 8 and 3 yr after surgical removal of the primary tumor. In the two cases, computerized tomographic scan showed that the adrenal tumor contained two components with low and high attenuation values, respectively. Uptake of iodocholesterol by the adrenal tumor in case 1 and elevated plasma ACTH-stimulated 17-hydroxyprogesterone values in case 2 strongly argued for the diagnosis of primary adrenocortical tumors. Enlargement of the adrenal mass during follow-up in case 1 and association of the adrenal lesion with a hepatic mass in case 2 led to adrenalectomy. In both cases, histological examination of the tumor demonstrated the presence of metastatic carcinoma tissue in an adrenocortical adenoma, allowing classification of the neoplasia as a collision/composite tumor. CONCLUSION: These observations show that collision/composite tumors of the adrenal gland formed by carcinoma metastasis in benign adenomas are a pitfall of iodocholesterol scintigraphy and/or plasma steroid assays to exclude the diagnosis of adrenal metastasis. Conversely, computerized tomographic scan is a useful tool for the distinction between the benign and malignant tissues in adrenal collision/composite tumors.