Can a Sebaceous Cyst Be Cancerous? What to Know

Sebaceous cyst usually refers to an epidermoid cyst, a keratin-filled pocket under the skin. A typical cyst may be smooth, rounded, slow to change, and sometimes marked by a small central opening. Inflammation can make it suddenly tender, red, or swollen. Those changes do not by themselves identify the cause, because infection and irritation can alter a cyst’s appearance.

A different skin growth can resemble a cyst, so a lump that is firm, fixed, rapidly changing, bleeding, ulcerated, or repeatedly returning needs professional assessment. Examination, and sometimes removal or laboratory examination of tissue, can clarify the diagnosis.

Do not squeeze, cut, or attempt to burn off the lump. Note when you first noticed it, whether it changes, and whether fluid, blood, pain, or warmth has appeared. Arrange a dermatology or primary-care review for a new, persistent, or unusual lump. Depending on the findings, care may be observation, treatment for inflammation, drainage of an abscess, or cyst removal.

Seek prompt care for fast enlargement, marked pain, spreading redness, warmth, pus, bleeding, an open sore, or a lump that feels fixed to deeper tissue. Get urgent help if you also have fever, severe illness, or swelling that affects vision, swallowing, or breathing. Do not wait for home treatment to explain a lump that is changing in several ways.

Ask what features support a cyst, what other diagnoses should be considered, and whether the lump should be monitored, treated, removed, or examined as tissue. Ask which changes should trigger an earlier review.