Right Parietal Skull Xanthoma Characterized as a Metastatic Deposit

Xanthomas are benign lipomatous deposits that can be found systemically in various tissues including bones. Their presence in the skull remains a rare entity. Despite their benign characteristics, imaging modalities are often unable to distinguish them from malignant lesions. This leads to a diagnostic dilemma in patients with underlying malignancy. This case report highlights such a case where clinical history of prostate cancer and image findings were concordant with that of metastatic deposit in the parietal skull region.

This 65-year-old gentleman was diagnosed with prostatic adenocarcinoma. During systemic workup for his tumor, he was found to have a right parietal skull lesion. Magnetic resonance imaging of the brain, as well as a bone scan, were consistent with that of a metastatic deposit. As treatment would be drastically affected by the diagnosis, an excision biopsy was performed. The histology was consistent with that of a bone xanthoma.

Xanthomas are benign lesions that can be seen deposited in appendicular and axial skeleton. Skull lesions are rare with most case descriptions focusing on their presence in the frontoorbital regions and mandible and temporal bone. They usually have a benign course but may present with symptoms due to localized mass effect. Surgical intervention and histologic diagnosis may still be required in these lesions due to their lack of imaging characteristics that confirm their diagnosis through noninvasive methods.