Calvarial hyperpigmentation

Abstract

Background: Osseous hyperpigmentation of the calvarium is an extremely rare finding with only few reported cases in literature.

Case description: The case is of a 59-year-old Caucasian male who presented with an acute history of generalized tonic clonic seizures and progressive weakness of the right upper limb. He had a background history of a malignant melanoma which had been resected from his left external acoustic meatus 4 weeks prior. Neuroimaging of the brain showed an intra-axial space-occupying lesion in his left parietal lobe with no associated osseous changes. A left mini parietal craniotomy was performed which revealed black discoloration of the parietal bone. The lesion was successfully resected and the bone flap was secured back in place. The patient was discharged on the 4^th day postoperatively with no complications. The unusual finding of black discoloration of the calvarium was found to be secondary to adolescent tetracycline use.

Conclusion: Calvarial hyperpigmentation is a phenomenon encountered incidentally and will often come as surprise for surgeons. Once encountered, thorough history taking and examination should be done to investigate the cause.

Keywords: Black bone disease; Craniofacial; Osseous hyperpigmentation; Skull.

Figure 1:

Axial T2-weighted fluid attenuated inversion recovery magnetic resonance imaging showing a left frontal intra-axial lesion with surrounding vasogenic edema.

Figure 2:

Intraoperative scalp dissection showing distinct discoloration of the parietal bone.

Figure 3:

Bone flap showing discoloration of the outer table, parts of the diploe (a) as well as the inner table (b).

Figure 4:

Postoperative axial contrasted computerized tomography of the brain showing gross total resection of metastatic malignant melanoma of the frontal lobe.