Lump on Back of Head: Causes, Red Flags & Diagnostic Approach

Posterior scalp/occipital lumps are common. Most are benign, but systematic evaluation is essential.

Common Benign Causes

Diagnosis	Features	Typical Location
Sebaceous cyst	Mobile, doughy, central punctum, may express keratin	Scalp, face, neck, trunk
Lipoma	Soft, lobulated, mobile, non-tender, slow-growing	Neck, shoulders, back, arms
Dermoid cyst	Midline, present at birth, may have hair/skin appendages	Occiput, forehead, orbit
Pilomatricoma	Hard, "rock-like," mobile, skin tenting (teeter-totter sign)	Head, neck, upper arms (children/young adults)
Hematoma	Post-traumatic, fluctuant → firm, resolving over weeks	Site of injury
Occipital lymph node	Rubbery, mobile, <1 cm, reactive (scalp infection, viral)	Occipital region

Concerning Features (Need Urgent Evaluation)

• Rapid growth (>1 cm/month)
• Fixed to bone/deep fascia
• Skin changes: ulceration, pigmentation, telangiectasia
• Pain, neurological symptoms
• Associated systemic symptoms (weight loss, night sweats)

Diagnostic Workup

1. Focused H&P (onset, trauma, growth rate, symptoms)
2. Ultrasound (first-line: cystic vs. solid, vascularity, depth)
3. MRI if deep extension suspected or preoperative planning
4. Excisional biopsy (preferred) or core needle if large/deep

Treatment by Diagnosis

• Sebaceous cyst / lipoma / pilomatricoma → excision if symptomatic/cosmetic
• Dermoid → excision (risk of intracranial extension if midline posterior)
• Lymph node → treat cause; biopsy if persistent >4 weeks or suspicious
• Malignancy (melanoma, SCC, Merkel, metastasis) → wide excision ± SLNB ± adjuvant

Don't panic — but don't ignore. A surgeon or dermatologist can usually diagnose in one visit.