Bump with a Black Dot: Differential Diagnosis from Benign to Malignant

A papule with a central dark punctum (“black dot”) has a focused differential. Dermoscopy is key for accurate classification.

Common Benign Lesions

• Sebaceous Hyperplasia: Yellowish, soft, 2–5 mm, central umbilication (follicular opening); face, forehead, chest. Benign sebaceous gland enlargement.
• Dilated Pore of Winer: Large, solitary, keratin-filled follicular ostium; expresses cylindrical plug. Benign.
• Cherry Angioma: Bright red/purple dome; may develop central thrombosis (dark dot); trunk, extremities; increases with age.
• Melanocytic Nevus (Mole): Uniform pigment, symmetric; central dark dot may be hair follicle or pigment concentration. Monitor for ABCDE changes.
• Dermatofibroma: Firm, tethered, dimples on pinch; hyperpigmented ring; often legs.
• Seborrheic Keratosis: “Stuck-on,” waxy, verrucous; may have horn cysts (white/yellow) or pigment plugs (black dots).

Malignant / Concerning Lesions

• Nodular Melanoma: Rapidly growing, firm, symmetric nodule; may be amelanotic or dark; central dell/ulceration. “EFG” (Elevated, Firm, Growing).
• Basal Cell Carcinoma (Pigmented): Pearly border, telangiectasia, blue-black globules; central crust/ulceration.
• Squamous Cell Carcinoma: Hyperkeratotic, indurated, ulcerated; actinic damage field.
• Merkel Cell Carcinoma: Rapidly growing red/purple nodule; sun-exposed; elderly/immunosuppressed.

Dermoscopy Clues

• Sebaceous hyperplasia: “cumulus” vessels, central pore.
• Melanoma: atypical network, blue-white veil, irregular dots/globules, regression structures.
• BCC: arborizing vessels, ulceration, blue-gray ovoid nests.
• SK: comedo-like openings, milia-like cysts, fissures.

Action Plan

1. Do not squeeze or traumatize.
2. Photograph with scale (ruler).
3. See a dermatologist for dermoscopy.
4. Biopsy if any suspicion (changing, symptomatic, dermoscopy concerning).

Most “black dot” bumps are benign, but melanoma and pigmented BCC must be excluded.