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 Table of Contents     
CASE REPORT
Year : 2018  |  Volume : 33  |  Issue : 4  |  Page : 345-347  

Adrenal oncocytoma: An incidental fluorodeoxyglucose positron emission tomography/computed tomography findings with magnetic resonance imaging correlation


Department of Radiology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia

Date of Web Publication9-Oct-2018

Correspondence Address:
Mohei Abouzied
Department of Radiology, King Faisal Specialist Hospital and Research Center, P.O. Box. 3354, Riyadh 11211
Saudi Arabia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijnm.IJNM_78_18

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   Abstract 


A good percentage of adrenal masses in patients with known malignancy may be benign; thus, noninvasive characterization is important in preventing unnecessary biopsy. This case report represents a patient with papillary thyroid carcinoma and known lung metastasis for which she was followed up with whole-body fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) postradioactive iodine therapy. During the follow-up, she had developed an adrenal mass lesion seen by FDG PET/CT and further characterized by magnetic resonance imaging (MRI). This case demonstrates the potential importance of combining the molecular characterization by FDG PET/CT with the data derived from MRI in narrowing the differential diagnosis of an adrenal mass and suggesting the next diagnostic step in reaching the definitive diagnosis.

Keywords: Adrenal oncocytoma, fluorodeoxyglucose, magnetic resonance imaging, positron emission tomography/computed tomography


How to cite this article:
Alsugair K, Al Obaidy M, Al Qahtani M, El Saadany AM, Abouzied M. Adrenal oncocytoma: An incidental fluorodeoxyglucose positron emission tomography/computed tomography findings with magnetic resonance imaging correlation. Indian J Nucl Med 2018;33:345-7

How to cite this URL:
Alsugair K, Al Obaidy M, Al Qahtani M, El Saadany AM, Abouzied M. Adrenal oncocytoma: An incidental fluorodeoxyglucose positron emission tomography/computed tomography findings with magnetic resonance imaging correlation. Indian J Nucl Med [serial online] 2018 [cited 2019 Nov 12];33:345-7. Available from: http://www.ijnm.in/text.asp?2018/33/4/345/242945




   Introduction Top


The improvement of imaging technique has led to an increase in the incidentally discovered adrenal lesions. Characterization of such lesions has become a necessity and an increasingly common management scenario for endocrinologists and urologists. Functional imaging technique usually complement the rule of structural imaging with CT and MRI in reaching a sensible conclusion about most of these lesions as it will be illustrated in the case report.


   Case Report Top


A 45-year-old female presented with a previous history of papillary thyroid carcinoma posttotal thyroidectomy and radioactive iodine ablation therapy.

She had developed lung metastases from thyroid origin for which she was followed up with whole-body fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) postradioactive iodine therapy.

A follow-up whole-body FDG PET/CT scan revealed a well-defined left adrenal mass lesion that had mild FDG uptake with a mean standardized uptake value (SUV) higher than both the liver and background SUV [Figure 1], which has been further characterized by a dedicated magnetic resonance imaging (MRI) of the abdomen [Figure 2]a,[Figure 2]b,[Figure 2]c,[Figure 2]d,[Figure 2]e,[Figure 2]f,[Figure 2]g,[Figure 2]h,[Figure 2]i,[Figure 2]j,[Figure 2]k,[Figure 2]l showing a 3.4 cm × 3 cm, well-defined, fairly homogenous lesion anterosuperior to the left kidney, which demonstrates slightly low T2 signal intensity to the adjacent renal cortex on half-Fourier single-shot technique (a), T2 fat-saturated images (b), increased signal on diffusion images (c), and low signal on apparent diffusion coefficient map images (d), compatible with diffusion restriction. It has iso-signal intensity to the adjacent renal cortex on the in-phase T1-weighted images (e), without drop of signal on the opposed-phase images (f), excluding the presence of intracellular fat.
Figure 1: Coronal whole-body 18fluorodeoxyglucose positron emission tomography computed tomography (a), axial computed tomography (b), axial positron emission tomography (c), and fused axial positron emission tomography/computed tomography (d) showing an well-defined 3.4-cm mass lesion (red arrow) involving the left adrenal region that has an standardized uptake value average of 1.7 with an average hounsfield unit of 37; its standardized uptake value average is slightly higher than the liver standardized uptake value average which is 1.2 that would be in favor of neoplastic process rather than benign adrenal adenoma

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Figure 2: (a) Axial T2 half-Fourier acquisition single-shot turbo spin echo, (b) axial fat-saturated T2 fast spin echo, (c) axial diffusion, (d) apparent diffusion coefficient map, axial (e) in- and (f) out-of-phase T1 gradient echo, axial (g) pre- and postcontrast three-dimensional-gradient echo fat-saturated T1-weighted images during the (h) arterial, (i) portal venous, and (j) delayed phases, (k) coronal, and (l) sagittal postcontrast three-dimensional-gradient echo fat-saturated T1-weighted images

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It demonstrates arterial hyperenhancement (h) and washes out on subsequent postcontrast images (i-j) splaying the left adrenal gland limbs (arrows, k-l), consistent with an adrenal origin. Overall findings are highly suspicious for a neoplastic adrenal lesion. Subsequently, the patient underwent open left adrenalectomy.

Five-centimeter of the left adrenal mass was resected for which the histopathology was consistent with oncocytic adrenocortical neoplasm of borderline category of uncertain malignant potential according to Lin–Weiss–Bisceglia system for the assessment of malignant potential in oncocytic adrenocortical tumors; this lesion was confined to the adrenal gland without vascular invasion and with free surgical margin.


   Discussion Top


Oncocytic neoplasms are benign neoplasms that have been predominantly described in organs such as the kidney, thyroid, ovaries, lung, and salivary and pituitary glands.[1]

However, oncocytic adrenal cortical neoplasms are considered very rare, with only around fifty cases reported in English literature.[2]

Nonetheless, with the advancement of imaging techniques, recent literatures have demonstrated an increase in its detection by up to 5%.[3] Most of these “adrenal incidentalomas” are benign and nonfunctioning, discovered without its relation to the patient's underlying symptoms. Although extremely rare, malignant and functioning tumor cases have been reported simultaneously associated with Cushing's syndrome.[1],[3],[4]

Most adrenal oncocytomas have been reported between the ages of 27 and 72 years with female predisposition to male.[5],[6] Grossly, these tumors are described as well-circumscribed, round encapsulated masses with areas of hemorrhage and cystic formation. Histologically, their cytoplasm is highly granular and eosinophilic due to the abundance of mitochondria.[7]

In our patient's clinical scenario, metastasis to the adrenal gland is considered one of the top differential diagnostic possibilities. The most common primary sites are the lung, breast, skin or integument (melanoma), kidney, thyroid gland, and colon.

Nearly 50% of adrenal masses incidentally detected in patients with cancer harbor metastases; most of them are silent, putting these patients at higher risk. Therefore, the characterization of these masses in this subset of patients is considered vital for noninvasive staging of the tumor, selection of the treatment regimen, and prediction of the prognosis.[8],[9],[10]

FDG PET–CT can help to differentiate benign from malignant adrenal lesions with average diagnostic sensitivities of 93%–100%, specificities of 90%–96%, and accuracies of 92%–96%.[10],[11],[12],[13],[14] Qualitative (visual) PET analysis has the best combined test sensitivity and specificity for PET characterization of malignant adrenal masses.[10]

Therefore, relying solely on the metabolic features and the patient's clinical history would favor the malignant potential of such lesion. However, MRI findings have supported further such hypothesis by excluding fat-rich adenoma based on the nondrop of signal on the opposed-phase-1-weighted images[15] and that contributed to an increase in the specificity of PET findings since benign adenoma might have shown the same metabolic features on the FDG study.


   Conclusion Top


Clinical history and metabolic features of the adrenal lesion complemented by structural imaging (CT/MRI) features were helpful in favoring the malignant potential of such adrenal mass that triggered the surgical intervention. Even though adrenal oncocytic neoplasm is a rare tumor, it should be considered in the differential diagnosis of a well-defined adrenal mass.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest



 
   References Top

1.
Tartaglia N, Cianci P, Altamura A, Lizzi V, Vovola F, Fersini A, et al. A rare case of functioning adrenocortical oncocytoma presenting as Cushing syndrome. Case Rep Surg 2016;2016:8964070.  Back to cited text no. 1
    
2.
Shenouda M, Brown LG, Denning KL, Pacioles T. A case of oncocytic adrenocortical neoplasm of borderline (Uncertain) malignant potential. Cureus 2016;8:e638.  Back to cited text no. 2
    
3.
Shah VN, Premkumar A, Walia R, Kumar S, Nahar U, Bhansali A, et al. Large but benign adrenal mass: Adrenal oncocytoma. Indian J Endocrinol Metab 2012;16:469-71.  Back to cited text no. 3
    
4.
Kabayegit OY, Soysal D, Oruk G, Ustaoglu B, Kosan U, Solmaz S, et al. Adrenocortical oncocytic neoplasm presenting with Cushing's syndrome: A case report. J Med Case Rep 2008;2:228.  Back to cited text no. 4
    
5.
Pazooki A, Vaziri M. Incidental adrenocortical oncocytoma. Case Rep 2009. pii. bcr1220081405.  Back to cited text no. 5
    
6.
Bisceglia M, Ludovico O, Di Mattia A, Ben-Dor D, Sandbank J, Pasquinelli G, et al. Adrenocortical oncocytic tumors: Report of 10 cases and review of the literature. Int J Surg Pathol 2004;12:231-43.  Back to cited text no. 6
    
7.
Goel T, Thomas J, Garg S, Rao AC, Reddy S. Adrenal oncocytoma masquerading as a functional tumor. Indian J Urol 2007;23:77-8.  Back to cited text no. 7
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8.
Caoili EM, Korobkin M, Francis IR, Cohan RH, Platt JF, Dunnick NR, et al. Adrenal masses: Characterization with combined unenhanced and delayed enhanced CT. Radiology 2002;222:629-33.  Back to cited text no. 8
    
9.
Khan M, Caoili EM, Davenport MS, Poznanski A, Francis IR, Giordano T, et al. CT imaging characteristics of oncocytic adrenal neoplasms (OANs): Comparison with adrenocortical carcinomas. Abdom Imaging 2014;39:86-91.  Back to cited text no. 9
    
10.
Boland GW, Dwamena BA, Jagtiani Sangwaiya M, Goehler AG, Blake MA, Hahn PF, et al. Characterization of adrenal masses by using FDG PET: A systematic review and meta-analysis of diagnostic test performance. Radiology 2011;259:117-26.  Back to cited text no. 10
    
11.
Gupta NC, Graeber GM, Tamim WJ, Rogers JS, Irisari L, Bishop HA, et al. Clinical utility of PET-FDG imaging in differentiation of benign from malignant adrenal masses in lung cancer. Clin Lung Cancer 2001;3:59-64.  Back to cited text no. 11
    
12.
Kumar R, Xiu Y, Yu JQ, Takalkar A, El-Haddad G, Potenta S, et al. 18F-FDG PET in evaluation of adrenal lesions in patients with lung cancer. J Nucl Med 2004;45:2058-62.  Back to cited text no. 12
    
13.
Jana S, Zhang T, Milstein DM, Isasi CR, Blaufox MD. FDG-PET and CT characterization of adrenal lesions in cancer patients. Eur J Nucl Med Mol Imaging 2006;33:29-35.  Back to cited text no. 13
    
14.
Yun M, Kim W, Alnafisi N, Lacorte L, Jang S, Alavi A, et al. 18F-FDG PET in characterizing adrenal lesions detected on CT or MRI. J Nucl Med 2001;42:1795-9.  Back to cited text no. 14
    
15.
Outwater EK, Siegelman ES, Radecki PD, Piccoli CW, Mitchell DG. Distinction between benign and malignant adrenal masses: Value of T1-weighted chemical-shift MR imaging. AJR Am J Roentgenol 1995;165:579-83  Back to cited text no. 15
    


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