Imaging technologies in the differential diagnosis and follow-up of brown tumor in primary hyperparathyroidism: Case report and review of the literature

Abstract

Brown tumors are osteolytic lesions associated with hyperparathyroidism (HPT). They may involve various skeletal segments, but rarely the cranio-facial bones. We report a case of a young boy with a swelling of the jaw secondary to a brown tumor presenting as the first manifestation of primary HPT (PHPT). He was found to have brown tumor located in the skull, as well. Different imaging technologies were employed for the diagnosis and follow-up after parathyroidectomy. We enclose a review of the literature on the employment of such imaging technologies in the differential diagnosis of osteolytic lesions. A multidisciplinary approach comprising clinical, laboratory and imaging findings is essential for the differential diagnosis of brown tumor in PHPT.

Keywords: Brown tumor; MRI; Parathyroid adenoma; Primary hyperparathyroidism.

Fig. 1

a) Ultrasound image showing the parathyroid adenoma as an oblong hypo-echoic and capsulated lesion with signal color-Doppler of monopolar vascular pattern referred to as the arc or rim sign, posterior-inferiorly to the left thyroid lobe; b) Axial T2 IDEAL Fat Suppressed MRI image depicting hyperintense parathyroid adenoma posterior-inferiorly to the left thyroid lobe, and separated from the thyroid gland (arrow); c) 99-mTc sestamibi scan demonstrating a residual uptake on left side 2 h after the radiotracer administration (arrow); d) X-ray image of the skull showing an osteolytic lesion with lobulated margin in the right parietal bone (arrow); e) Sagittal post-contrast T1-weighted MRI image showing enhancement of the parathyroid adenoma and of the jaw brown tumor (arrow); f) 99-mTc scan demonstrating uptake of the jaw bone and of the right parietal lobe of the skull (arrow).

Fig. 2

Six-month post-surgery images. a) Parathyroid adenoma; b) Axial T2 IDEAL Fat Suppressed MRI image showing surgical resection of the parathyroid adenoma and of the left thyroid lobe (arrow); c) Sagittal post-contrast T1-weighted MRI showing almost absent contrast enhancement of the brown tumor, excluding persistence of contrast peripheral enhancement in some areas of the lesion (arrow); d) X-ray image of the skull showing no evidence of the previous osteolytic lesion in the right parietal bone.