Skull Parosteal Lipoma - Hard Lump on the Head of Bony Origin?

Aims: A skull parosteal lipoma is extremely rare with only 4 cases reported in the recent literature. This is in contrast to other parosteal lipomas that occur more commonly in the long bones of the upper and lower limbs. In this report, we present the fifth case of skull parosteal lipoma according to our comprehensive literature review.

Case Presentation: A 67-year old gentleman with well controlled hypertension presents with a painless right frontal swelling of three year’s duration. He recalls prior blunt injury to the right frontal area 6 years ago. Magnetic resonance (MR) imaging scan of the head was performed and demonstrated a well-circumscribed subperiosteal lesion in an otherwise asymptomatic patient. With a diagnosis of a benign lesion that was asymptomatic, the patient was not offered surgery and the lesion has since remained stable.

Discussion: The aetiology of parosteal lipoma is unknown. Local trauma on long bones has been associated with subsequent parosteal lipoma several years later. In this patient, we suggest that there may be possible association with previous trauma. MR imaging can delineate the tissue layer of origin and demonstrate a lesion with the same attenuation value and intensity signal as adipose tissue.

Conclusion: A skull parosteal lipoma may be differentiated from other differentials with adequate physical examination and appropriate imaging technique. MR imaging has been shown to be useful to exclude other differentials such as an angular dermoid cyst. Surgical resection with wide excision margins may be performed to obtain a histopathological diagnosis.