Localization of occult adrenal tissue with cosyntropin-stimulated 18F-FDG-PET/CT in a patient with metachronous adrenocortical tumor who presented with persistently elevated SDHEA after bilateral adrenalectomy
M. Franco1, G. Alencar1, A. Faria1, J. Bezerra2, C. Cruz2, S. Domenice1, L. Lima1, A. Lerario1, M. Almeida1, A. Latronico1, B. Mendonca1 & M. Fragoso1
Introduction: Adrenocortical carcinoma (ACC) is a rare and potentially fatal disease in childhood. Complete resection of the tumor and metastasis can improve survival. Case: A 2.6 year-old boy presented isosexual pseudo-precocious puberty at 2.1 years. CT revealed a single nodule in the left adrenal (2 cm) which was resected by adrenalectomy. Histology revealed an adrenocortical tumor (2 cm, 3.0 g, Weiss score 4), ENSAT stage I. Partial regression of the puberty features and normalization of hormonal levels were observed. At 4.8 years, recurrence was observed, with high androgen levels and an 8 cm right adrenal mass on CT. Right adrenalectomy and nephrectomy was performed, which revealed an adrenocortical tumor (8 cm, 30 g, Weiss score 7) with no apparent metastasis at that time. At 6 years, DHEAS levels became increasingly high and CT showed a pulmonary nodule that was surgically removed. After 8 months of partial lung resection, abnormally high DHEAS was present with no obvious source on conventional imaging techniques. 18F-FDG-PET/CT showed a mediastinal lesion that was resected and histologically confirmed as metastatic ACC. DHEAS levels remained undetectable until he was 13 years-old, with a progressive increase not suppressible by high doses of dexamethasone (0.5 mg qid for 7 days). Conventional radiological techniques did not identify any metastatic lesions. At 18.5 years of age, the patient underwent 18F-FDG-PET/CT under stimulation with intravenous cosyntropin 250 mgc, which identified a 1.5 cm nodular lesion in left adrenal topography. FDG hypermetabolism was shown in that area pre-stimulus (SUV=1.5), with an increase 60 min after stimulation to 3.6, suggesting remaining tumorous tissue.
Conclusions: We report a long-term evolution of a pediatric patient with an indolent ACC and suspected local recurrence identified by cosyntropin-stimulated 18F-FDG-PET/CT. This new diagnostic modality may be used in clinical practice to locate occult metastasis of ACC.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.