fdg-pet in two cases of neurofibromatosis type 1 and atypical malignancies

Abstract

Patients with neurofibromatosis type 1 (nf1) are at increased risk for both benign and malignant tumours, and distinguishing the malignant potential of an individual tumour is a common clinical problem in these patients. Here, we review two cases of uncommon malignancies (Hodgkin lymphoma and mediastinal germ-cell tumour) in patients with nf1. Although (18)F-fluorodeoxyglucose positron-emission tomography (fdg-pet) has been used to differentiate benign neurofibromas from malignant peripheral nerve sheath tumours, fdg-pet characteristics for more rare tumours have been poorly described in children with nf1. Here, we report the role of pet imaging in clinical decision-making in each case. In nf1, fdg-pet might be useful in the clinical management of unusual tumour presentations and might help to provide information about the malignant potential of uncommon tumours.

Keywords: Hodgkin lymphoma; Klinefelter syndrome; Neurofibromatosis type 1; germ-cell tumours; pediatric oncology.

FIGURE 1

Case 1. (A) Initial coronal and axial magnetic resonance short T1 inversion recovery images of left axillary Hodgkin lymphoma, (B) with corresponding coronal fluorodeoxyglucose (fdg) positron-emission tomography (pet) image and axial fdg-pet–computed tomography (ct) image. (C) Coronal fdg-pet and axial fdg-pet–ct images 3 months after surgery show a new focus of fdg uptake in the left pectoralis major muscle.

FIGURE 2

Case 2. (A) Axial and coronal magnetic resonance short T1 inversion recovery images of the left thorax tumour with mass effect on the mediastinum. (B) Corresponding coronal fluorode-oxyglucose (fdg) positron-emission tomography (pet) and axial fdg-pet–computed tomography images of the same mass.