Clinical utility of nuclear imaging in the evaluation of pediatric adrenal neoplasms

Abstract

Adrenal neoplasms rarely occur in children. They can be diagnosed in the presence of endocrine, metabolic or neurological problems, an abdominal mass, more rarely an adrenal incidentaloma, or in the context of an adrenal mass discovered in the evaluation of childhood cancer including hematologic malignancy. According to standard medical practice, pediatric malignancies are almost always evaluated by ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography ([¹⁸F]FDG PET/CT). Nuclear imaging using specific radiotracers is also an important tool for diagnosing and staging neuroblastoma, pheochromocytoma, hormone hypersecretion, or indeterminate adrenal masses. The Hippocratic oath "primum non nocere" encourages limitation of radiation in children per the ALARA concept (as low as reasonably achievable) but should not lead to the under-use of nuclear imaging because of the potential risk of inaccurate diagnosis or underestimation of the extent of disease. As in adults, nuclear imaging in children should be performed in conjunction with hormone evaluation and morphological imaging.

Keywords: PET; adrenal; cushing; neuroblastoma; nuclear imaging; pediatric neoplams; pheochromocytoma.

Figure 1

Neuroblastoma. 2-week-old boy with neuroblastoma. [¹²³I]I-mIBG posterior planar image (A), [¹²³I]I-mIBG SPECT transverse image (B), CT for attenuation correction (C), [¹²³I]I-mIBG SPECT/CT fusion image (D), Diagnostic CT (E). Intense uptake in right adrenal mass on [¹²³I]I-mIBG scan (arrows).

Figure 2

Pheochromocytoma. 11-year-old boy with pheochromocytoma. [¹²³I]I-mIBG anterior planar image (A), transverse [¹²³I]I-mIBG SPECT (B), [¹²³I]I-mIBG posterior planar image (C), Fusion [¹²³I]I-mIBG SPECT/CT (D), Diagnostic CT (E). Intense uptake of [¹²³I]I-mIBG in right adrenal mass (arrows).

Figure 3

Metastatic pheochromocytoma. The maximum intensity projection images of [⁶⁸Ga]Ga-DOTATATE PET (A), [¹⁸F]FDG PET (B), ¹⁸F-fluorodopamine ([¹⁸F]FDA) PET (C), 6-[¹⁸F]FDOPA PET (D), and [¹²³I]I-mIBG SPECT/CT (E, F) of a 16-year-old boy with metastatic PPGL carrying a germline mutation in SDHB gene demonstrates a 5.7-cm left lesion in the adrenal/periadrenal region abutting the left upper renal pole along with lesions in the abdomen, mesentery, left peri-rectal and precarinal (red arrows) regions, and skull (green arrow). The [⁶⁸Ga]Ga-DOTATATE PET detects an additional lesion in skull bone (blue arrow); however, 6-[¹⁸F]FDOPA failed to detect any lesions.

Figure 4

Adrenocortical adenoma. 5-year-old girl with history of neuroblastoma 4 years earlier. Suspected recurrence of neuroblastoma. Adrenal lesion noted on ultrasound as part of an evaluation of the urinary tract. [¹⁸F]FDG PET shows uptake in a right adrenal mass. Surgical resection of 2.5-cm adrenal adenoma. Transverse PET (A), CT (B), PET/CT fusion image (C). Intense [¹⁸F]FDG uptake in a right adrenal mass (arrows).

Figure 5

Adrenocortical carcinoma. 13-year-old girl with hyperandrogenism (secondary amenorrhea, hirsutism). Large adrenal mass on US and CT scan. [¹⁸F]FDG PET shows uptake in a left adrenal mass without metastasis. After surgery, pathological analysis confirmed the diagnosis of ACC with Wieneke score 3 (55), Ki-67 index 5.3% and p53-negative status. Complete remission 5 years after surgery. Maximum intensity projection image (A) Transverse CT (B), PET (C), PET/CT fusion image (D). (Courtesy of Drs. Catherine Ansquer and Morgane Cleirec from Nantes University Hospital/Hôtel-Dieu).