Multiple Brown Tumors within the Cranium, in a Patient with Primary Hyperparathyroidism. A Case Report and Review of the Literature

Background: Brown tumors are benign, lytic, and expansile bony lesions that arise as a delayed consequence of untreated hyperparathyroidism (HPT). Although they can arise within any part of the skeleton, their occurrence at the cranium or skull base is exceedingly rare. Moreover, the literature is really scarce on reports of multiple skull base and calvarial brown tumors, with only three identified reports of such presentation. Therefore, their anticipation among a list of differential diagnoses would be extremely difficult, especially when other signs and symptoms of HPT are absent at first clinical presentation. We therefore present what we understand is the fourth case of brown tumors under this category, with more than four sizable lesions detected, and an aggressive behavior that nearly caused the patient total blindness.

Case Description: A 28-year-old pregnant lady, presented with a 2-month history of gradual right eye proptosis and decreased vision, acute left eye visual loss for 1 day and epistaxis. She had no light perception in the left eye and was able to count fingers in the right eye. Magnetic resonance imaging (MRI) of the brain revealed multiple lesions, most significantly a 4 cm × 5.3 cm × 5 cm skull base mass occupying the nasopharynx with involvement of clivus and sphenoid sinus. Another large lesion was at the right sphenoid bone with extension into the right orbital wall with extension to the conal spaces superiorly, associated with peripheral cysts formation in the superior aspect of the orbits. The patient underwent nasopharyngeal biopsy and was discharged. A week later after histopathology result showed multiple giant cells, she was investigated for primary hyperparathyroidism. Patient was then admitted for parathyroid adenoma resection, followed by right decompressive craniotomy for salvaging the vision in the right side. The patient recovered well with improved right eye movement, proptosis, and vision without any perinatal complications.

Conclusion: High index of clinical suspicion and prior knowledge of this disease entity are mandated to include brown tumors of the skull base as a differential diagnosis for any lytic bony lesions, even if multiple. Management includes identifying and curing the cause of HPT, and biopsying the bony lesions to rule out other possible differentials. This however should not preclude from a decompressive surgery whenever acute deficits from neural compression are evident.

Fig. 1 Hypoechoic nodule inferior to the right lobe measures 1.3 cm × 0.6 cm × 1.5 cm in keeping with parathryroid adenoma (black arrow).

Fig. 2 (A, B) Axial and (C) Coronal contrast enhanced brain CT showing the left lesion occupying the nasopharynx, clivus and sphenoid sinus, and the lesion at the right sphenoid bone with extension into the orbital wall, and (D) showing the right parietotemporal lytic lesion. (E, F) Axial T2W MRI brain demonstrating the heterogeneously hyperintense skull base lesions, and (G) demonstrating the frontal sinus isolated lesion. (H) Coronal T2W MRI brain showing the two skull base lesions with separate focus of origin. CT, computed tomography; MRI, magnetic resonance imaging; T2W, T2-weighted.

Fig. 3 The lesion shows numerous multinucleated giant cells with bland monotonous oval and spindle cells in between. (H&E, original magnification ×10 [A], and ×20 [B]). H&E, hematoxylin and eosin.

Publication History

Article published online:
12 February 2021