Parosteal lipoma of the supra-auricular region.

Abstract

Background: Parosteal lipomas are rare benign soft-tissue tumors that develop in close association with the periosteum. Skull involvement is exceptionally uncommon, with only a few cases reported in the literature.

Case description: A 14-year-old female presented with a slowly enlarging, painless lump above her right ear, first noticed at the age of five. Physical examination revealed a firm, well-defined, immobile mass measuring 2.5 × 1.5 cm in the supra-auricular region. A non-contrast computed tomography scan demonstrated a hypodense mass with thickening of the underlying squamous and mastoid bones, along with mastoid air cell enlargement. Surgical excision was performed for cosmetic reasons and histopathological diagnosis. Intraoperatively, the mass was found to be adherent to the periosteum and underlying bone. Histopathological examination confirmed the diagnosis of parosteal lipoma, showing mature adipose tissue, fibrous tissue, and focal lymphocytic aggregates without signs of malignancy. The patient recovered well postoperatively, with no recurrence or complications over 6 months of follow-up.

Conclusion: Parosteal lipomas of the skull are exceedingly rare and require clinical suspicion for diagnosis. Imaging aids in preoperative planning, while histopathological assessment confirms the diagnosis. Complete surgical excision is curative, with a favorable prognosis. This case adds to the limited literature on skull-based parosteal lipomas.