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18F-FDG PET reveals an adrenocortical carcinoma in a bilateral adrenal multinodular disease
Rossella Libe 1 . Jean-François Jazeron2 . Estelle Louiset3 . Lionel Groussin1
Received: 7 August 2018 / Accepted: 9 September 2018 @ Springer Science+Business Media, LLC, part of Springer Nature 2018
A 48-year-old man underwent an abdominal computed tomography (CT) scan for asthenia. The CT scan revealed bilateral adrenal masses. The left mass measured 47 x 27 mm with a spontaneous density (SD) of -6 Hounsfield Unit (HU), in favor of a benign adrenocortical lesion (adenoma if <10 HU). The right adrenal presented one anterior nodule of 28 × 23 mm with a SD of -25 UH, in favor of a benign lesion and a second posterior nodule of 21 × 25 mm, with a high SD of 27 UH and an absolute washout of 55% (>60% in case of a benign lesion), con- sistent with an indeterminate lesion (Fig. 1a). The patient was lost of follow-up. After 1 year, the patient was referred to our hospital for hypertension, hypokalaemia and android obesity. Hormonal investigations showed an ACTH- independent hypercortisolism (Urinary free cortisol: 373 nmol/24 h (normal values:69-248), ACTH <2 pmol/l (normal values 2 to 13)). The CT scan showed an increase in the posterior right adrenal mass (85×66 mm) with multiple retroperitoneal lymph nodes. The anterior right and left adrenal masses were unchanged (Fig. 1b).
18F-FDG PET/CT scan showed a high uptake localized to the posterior right mass (SUVmax = 18, adrenal/liver SUVmax ratio = 8.6) without any uptake at the anterior right and left adrenal masses (Fig. 1c). The patient under- went bilateral adrenalectomy and para-aortic lymphade- nectomy. Pathology showed bilateral adrenal hyperplasia associated to a right posterior adrenocortical carcinoma (ACC) and multiple metastatic lymph nodes. The ACC had a Weiss score of 7 with a high Ki67 proliferative index (30%), whereas the adrenal hyperplasia showed no Ki67 immunostaining (Fig. 1d). Positive immunostaining for
GLUT1 (Fig. 1e) and hexokinase II (Fig. 1f) was restricted to the ACC.
To our knowledge, this is the first observation of an ACC associated to a bilateral macronodular hyperplasia. More- over, this case illustrates the rapid growth of an ACC during 1 year. Adrenocortical carcinoma is a rare disease, with an incidence of 0.7-2.0 cases/million habitants/year. The diagnosis of malignancy relies on careful investigations of clinical, biological, and imaging features before surgery and pathological examination after tumor removal. Most patients present with steroid hormone excess or abdominal mass effects, but 15% of ACC are diagnosed incidentally [1]. At initial evaluation, a careful characterization of the adrenal lesion by a CT scan is necessary, to measure the SD and calculate the washout after contrast injection [1]. This observation illustrates that in case of multiples adrenal nodules, a radiological assessment of all nodules is highly recommended. Moreover, if nodules with suspicious ima- ging characteristics are present, the use of 18F-FDG PET/ CT may help to predict the malignancy and facilitate the disease staging. Indeed, the adrenal/liver maxSUV ratio present a high sensitivity to diagnose ACC, the risk of false- negative results is quite low, more than 95% of ACC show a high 18F-FDG uptake [2]. GLUT1 and hexokinase II are known to be the most important glucose transporter and glycolytic enzyme in cancer cells. In a previous study, ACC patients with strong GLUT1 staining showed a considerably higher overall mortality compared with patients with no GLUT1 staining [3]. Interestingly, in this case we demon- strated a GLUT1 and hexokinase II overexpression limited to the ACC, in correlation with the 18F-FDG uptake.
☒ Rossella Libé rossella.libe@aphp.fr
1 COMETE Cancer Network for Adrenal Cancers, Department of Endocrinology, Cochin Hospital, Paris, France
2 Pathology Unit, Groupe Hospitalier La Rochelle, La Rochelle, France
3 Normandie Univ, UNIROUEN, INSERM, DC2N, 76000 Rouen, France
A
B
After one year
25 HU
6 HU
27 HU
C
D
Ki 67
*
+
**
E
GLUT-1
F
HEXO
*
*
**
Acknowledgements We thank the “Association Surrénales” for their technical assistance.
Compliance with ethical standards
Conflict of interest The authors declare that they have no conflict of interest.
Informed consent Informed consent was obtain from the patient to publish this report
References
1. M. Fassnacht, W. Arlt, I. Bancos et al. Management of adrenal incidentalomas: European Society of Endocrinology Clinical Practice Guideline in collaboration with the European Network for the Study of Adrenal Tumors. Eur. J. Endocrinol. 175(2), G1-G34 (2016)
2. L. Groussin, G. Bonardel, S. Silvéra et al. 18F-Fluorodeoxyglucose positron emission tomography for the diagnosis of adrenocortical tumors: a prospective study in 77 operated patients. J. Clin. Endocrinol. Metab. 945, 1713-1722 (2009)
3. W. Fenske, H.U. Völker, P. Adam et al. Glucose transporter GLUT1 expression is an stage-independent predictor of clinical outcome in adrenocortical carcinoma. Endocr. Relat. Cancer 16, 919-928 (2009)