AOUNMB
Prominent 18F-FDG Uptake in the Adrenal Gland after Contralateral Adrenalectomy in a Known Case of Adrenocortical Oncocytic Carcinoma
Rakan Al-Rashdan, Mohammed Aljaberi, Ali Mohamedkhair, Akram Al- Ibraheem*
Department of Nuclear Medicine, King Hussein Cancer Center, Amman, Jordan
ARTICLEINFO
ABSTRACT
Article type: Case report
Adrenocortical carcinoma (ACC) is a rare type of cancer that is associated with a high rate of recurrence and poor prognosis. The main diagnostic approaches to adrenocortical cancer include CT scan, MRI and the promising role of 18F-FDG PET/CT. The main therapeutic approaches include radical surgery of local disease and recurrences, as well as adjuvant mitotane therapy.
Article history: Received: 25 Sep 2022
Revised: 11 Nov 2022
Accepted: 28 Nov 2022
The evaluation of adrenocortical carcinoma (ACC) could be difficult by using 18F- FDG PET/CT in view of the significant association between the 18F-FDG uptake and ACC. At the same time, not all adrenal glands with 18F-FDG uptake are considered to be malignant, so awareness of these various findings is substantial for ACC management, especially with limited data regarding the role of 18F-FDG PET/CT in ACC post-operative settings.
Keywords: Adrenocortical carcinoma 18F-FDG PET/CT Mitotane Adrenalectomy
This report discusses the case of a 47-year-old man with a history of left adrenocortical carcinoma who underwent adrenalectomy and received adjuvant mitotane therapy. 9 months after the surgery, a follow-up 18F-FDG PET/CT scan showed that the 18F-FDG uptake was prominent in the right adrenal gland without corresponding abnormal CT scan findings.
Please cite this paper as:
Al-Rashdan R, Aljaberi M, Mohamedkhair A, Al-Ibraheem A. Prominent 18F-FDG Uptake in the Adrenal Gland after Contralateral Adrenalectomy in a Known Case of Adrenocortical Oncocytic Carcinoma. Asia Ocean J Nucl Med Biol. 2023; 11(2): 181-184. doi: 10.22038/AOJNMB.2022.67950.1472
Introduction
Adrenocortical carcinoma (ACC) is a rare tumor with an incidence of 1 per million people. It is associated with a high recurrence rate and poor prognosis; radical surgery of the primary tumor as well as of the local and distant recurrences is the only curative approach. Mitotane therapy is an effective adjuvant treatment for patients with ACC because it has delayed-onset adrenal-specific cytotoxic effects. Metastasis to the lung, liver, and lymph nodes is common, while metastasis to bone is less frequent. Imaging modalities play a central role in primary tumor detection, staging, and extent of recurrence in ACC. Although the imaging diagnostic tools for ACC are mainly based on using computed tomography (CT) and magnetic resonance imaging (MRI). Additionally, There have been studies published in the past that
argue the role of 18F-FDG PET/CT as an emerging and promising tool in the management of ACC (1-5).
Case Report
A 47-year-old male patient presented with hypertension refractory to several drugs. Upon diagnostic workup, an abdominal CT showed an unexpected mass on the left adrenal gland. Further tests showed that the urine and blood both had a lot of cortisol, which confirmed the diagnosis of Cushing syndrome.
The patient had surgery to remove the left adrenal gland. Histopathological correlation confirmed the presence of adrenocortical carcinoma. The pathology report showed that the tumor size was 17x12x12 cm3, the tumor weight was 1370 grams, wide areas of necrosis were present with no capsular or vascular
* Corresponding author: Akram Al-Ibraheem. Department of Nuclear Medicine King Hussein Cancer Center, Amman, Jordan. Tel: +962-6-5300460, ext. 1721; Fax: +962-6-5353001; E-mail: albraheem@khcc.jo; akramalibrahim@gmail.com @ 2023 mums.ac.ir All rights reserved.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
invasion, and the mitotic figures were less than 5/50 HPF. Melan-A and Synaptophysin proteins were found in tumor cells.A small number of cells were positive for inhibin. It is noteworthy that all the results are negative for EMA, chromogranin, and PAN-CK. The Ki-67 index was also below 5%. Adjuvant mitotane therapy was initiated based on the findings of the oncocytic variant.
A contrast-enhanced abdominal CT scan taken one month after a left adrenalectomy showed a left suprarenal mass that was heterogeneously enhanced and suspicious for metastatic deposits versus post-operative changes. In
order to rule out residual or recurrent disease, an 18F-FDG PET/CT was performed ten days after the CE CT was originally conducted. After administration of 289 MBq of 18F-FDG, a PET/CT scan was performed. The 18F-FDG PET/CT scan showed an irregular soft tissue mass of 14 cm in the left suprarenal region with mild non-specific 18F-FDG uptake, which is considered a post-operative change as there is no significant FDG uptake also biopsy-proven to be negative for malignancy afterward. Figure 1 shows the right adrenal gland, which has normal structure and 18F-FDG activity.
A
B
c
The 18F-FDG PET/CT scan was done 9 months after the left adrenalectomy and mitotane therapy. An axial CT image showed a normal- sized right adrenal gland. Nevertheless, the PET and fused PET/CT images showed prominent
right adrenal gland 18F-FDG uptake (arrows, SUVmax=5.6) that was almost two times higher than the physiologic liver 18F-FDG activity as shown in Figure 2.
D
E
F
Discussion
This case report presents the case of a 47- year-old man with a history of left adreno- cortical carcinoma who underwent adrenal- ectomy and received adjuvant mitotane therapy. 9 months after the surgery, a follow-up 18F-FDG PET/CT scan showed prominent 18F- FDG uptake in the right adrenal gland without
corresponding abnormal CT scan findings.
There are limited data regarding the role of 18F-FDG PET/CT in post-operative settings of adrenocortical carcinoma. However, several studies indicate that 18F-FDG PET/CT has a promising role in staging, therapy planning, local disease recurrence, and distant metastasis detection. Also, 18F-FDG PET/CT can play a
complementary role with CT, especially in the presence of fibrosis or post-surgical changes (2). Although there is no major recommendation to use 18F-FDG PET/CT after surgery, one study mentioned that some centers used 18F-FDG PET/CT for following up adrenocortical carcinoma removal surgeries at a 6-month interval period (7).
It has been found that the sensitivity, specificity, and accuracy of both 18F-FDG PET/CT and contrast-enhanced CT at staging and recurrence were similar. One study found that the diagnostic abilities of 18F-FDG PET/CT were similar to or slightly higher than CT (6).
Another study showed that using PET in comparison to CT has a higher sensitivity for local disease recurrence (7).
In 1957, the first reported usage of mitotane therapy in the treatment of adrenocortical cancers (8) was due to its adrenocytolytic effect (9). Mitotane therapy given after resection surgery was linked to a longer time without cancer coming back (10).
Adrenocortical carcinomas appear as an enlarged mass with an inhomogeneous structure that displaces adjacent tissues on an unenhanced CT scan and as peripherally enhanced inhomogeneous masses with less central enhancement after intravenous contrast administration. At the same time, adreno- cortical cancers are considered 18F-FDG avid tumors on 18F-FDG PET/CT scans (11, 12).
Leboulleux et al. state that there is a significant association between the 18F-FDG uptake and the adrenocortical carcinoma mitotic rate (13).
However, not all adrenal glands with 18F-FDG uptake are considered to be malignant, as adrenal glands normally show 18F-FDG uptake but usually less than the liver (14).
There have been a few reported cases of increased 18F-FDG uptake greater than the liver within the normal adrenal gland, lasting up to 9 months after adrenalectomy for oncocytic variant ACC, with subsequent inhibition of cortisol production using mitotane therapy. This 18F-FDG uptake occurs most frequently during the first 6 months of mitotane treatment. Following the initial administration of mitotane therapy, patients are given high doses of corticosteroids, which is associated with high levels of Adrenocorticotropic hormone (ACTH). This increased 18F-FDG uptake is most likely due to the effect of ACTH stimulation. In such cases, this uptake is considered transient in 14- 29% of cases and should not be concerning for malignancy (1, 14).
Conclusion
This case presents a transient high 18F-FDG uptake in the remaining adrenal gland 9 months after an adrenalectomy and subsequent mitotane therapy. This uptake is considered transient and occurs mostly in the first 6 months of mitotane treatment. It should not be worrisome for malignancy.
Acknowledgements
We are grateful to the patient for his informed consent and permission for publishing this report.
Compliance with Ethical Standards
Funding: The authors received no financial support for the research, authorship or publication of this article.
Ethical approval
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed Consent
Informed consent was obtained from the patient for publication of his case/report and accompanying images.
References
1. Mpanaka I, Lyra VD, Kaltsas G, Chatziioannou SN. High (18) F-FDG uptake by the remaining adrenal gland four months after surgery and initiation of mitotane treatment in two patients with adrenocortical carcinoma. Hellenic journal of nuclear medicine. 2011; 14(2):168-72.
2. Deandreis D, Leboulleux S, Caramella C, Schlumberger M, Baudin E. FDG PET in the management of patients with adrenal masses and adrenocortical carcinoma. Hormones and Cancer. 2011; 2(6):354-62.
3. Else T, Kim AC, Sabolch A, Raymond VM, Kandathil A, Caoili EM, et all. Adrenocortical carcinoma. Endocrine reviews. 2014; 35(2): 282-326.
4. Becherer A, Vierhapper H, Pötzi C, Karanikas G, Kurtaran A, Schmaljohann J, et all. FDG-PET in adrenocortical carcinoma. Cancer Biotherapy and Radiopharmaceuticals. 2001; 16(4):289-95.
5. Kumar T, Nigam JS, Sharma S, Kumari M, Pandey J. Uncommon Metastasizing Site of Adrenocortical Carcinoma. Cureus. 2021; 13(5):e15267.
6. Takeuchi S, Balachandran A, Habra MA, Phan AT, Bassett RL, Macapinlac HA, et all. Impact of 18F-FDG PET/CT on the management of adrenocortical carcinoma: analysis of 106 patients. European journal of nuclear medicine and molecular imaging. 2014; 41(11):2066-73.
7. Ardito A, Massaglia C, Pelosi E, Zaggia B, Basile V, Brambilla R, et all. 18F-FDG PET/CT in the post-operative monitoring of patients with adrenocortical carcinoma. Eur J Endocrinol. 2015; 173(6):749-56.
8. Bergenstal DH. Regression of adrenal cancer and suppression of adrenal function in man by o, p’DDD. Transactions of the Association of American Physicians. 1959; 72:341-50.
9. Paragliola RM, Torino F, Papi G, Locantore P, Pontecorvi A, Corsello SM. Role of mitotane in adrenocortical carcinoma- review and state of the art. European endocrinology. 2018; 14(2):62.
10. Terzolo M, Angeli A, Fassnacht M, Daffara F, Tauchmanova L, Conton PA, et all. Adjuvant mitotane treatment for adrenocortical
carcinoma. New England Journal of Medicine. 2007; 356(23):2372-80.
11. Dong A, Cui Y, Wang Y, Zuo C, Bai Y. 18F-FDG PET/CT of adrenal lesions. American Journal of Roentgenology. 2014; 203(2): 245-52.
12. Kiseljak-Vassiliades K, Bancos I, Hamrahian A, Habra MA, Vaidya A, Levine AC, et all. American Association of Clinical Endo- crinology Disease state clinical review on the evaluation and management of adrenocortical carcinoma in an adult: a practical approach. Endocrine Practice. 2020; 26(11):1366-83.
13. Leboulleux S, Dromain C, Bonniaud G, Aupérin A, Caillou B, Lumbroso J, et all. Diagnostic and prognostic value of 18- fluorodeoxyglucose positron emission tomography in adrenocortical carcinoma: a prospective comparison with computed tomography. The Journal of Clinical Endo- crinology & Metabolism. 2006; 91(3): 920-5.
14. Leboulleux S, Deandreis D, Escourrou C, Al Ghuzlan A, Bidault F, Auperin A, et all. Fluorodesoxyglucose uptake in the remaining adrenal glands during the follow-up of patients with adrenocortical carcinoma: do not consider it as malignancy. European Journal of Endocrinology. 2011; 164(1):89-94.