Bumps on the Back of the Head: Sebaceous Cyst, Lipoma, Osteoma – How to Tell Them Apart

Three common benign scalp/occipital lesions:

Feature	Sebaceous Cyst	Lipoma	Osteoma
Origin	Blocked sebaceous gland	Adipose tissue	Bone (periosteum)
Consistency	Firm, fluctuant if large	Soft, doughy, mobile	Hard, fixed to skull
Content	Keratin, sebum (cheesy)	Mature fat	Compact bone
Punctum	Often visible central pore	None	None
Pain	Usually painless unless infected	Painless	Painless
Imaging	US: anechoic with wall	US: hyperechoic, encapsulated	X‑ray/CT: dense, well‑circumscribed

When to See a Doctor

• Rapid growth, color change, ulceration, pain.
• Multiple lesions (consider genetic syndromes: Gardner’s, familial multiple lipomatosis).
• Neurologic symptoms (rare osteoma compression).

Most require no treatment; excision if symptomatic, cosmetic concern, or diagnostic uncertainty.