Soft Tissue Masses — Skin Cysts

• Epidermoid and pilar cysts

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  Epidermoid cysts contain epidermal keratin; pilar (trichilemmal) cysts contain follicle-derived keratin. “Sebaceous cyst” is common in everyday language but most of these lesions are not true sebaceous-gland cysts. Exam and sometimes ultrasound help.

• Inflamed or infected cyst

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  Key note inside

  Redness, warmth, severe pain, and fever suggest infection — but a red epidermoid cyst is not always bacterial; inflammation or rupture can also cause pain and redness. Antibiotics plus urgent incision and drainage may be needed; elective complete excision is usually planned after inflammation settles. Fever and rapidly spreading redness need urgent assessment.

• Treatment options

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  Small quiet cysts may be watched. Recurrent infection, drainage, pain, or cosmetic concern favors complete excision with the cyst wall (capsule) removed intact — draining contents alone is not enough.

• Why do cysts recur?

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  Recurrence happens when the cyst wall is left behind or removed in fragments. The surgical goal is intact wall excision, which markedly lowers recurrence risk. Planned excision is often deferred during active infection.

More chapters in this hub

• Lipoma

  Benign fatty masses — when to observe or excise

• General Diagnosis

  Lipoma and skin cysts — exam, ultrasound, MRI

• General Treatment

  Lipoma and skin cysts — observation and excision

• Nevus

  Suspicious pigmented lesions — ABCDE and excision

• Nevus Diagnosis

  Dermoscopy, biopsy, and pathology pathway

• Nevus Treatment

  Excision, wide local excision, and follow-up

• Liposarcoma

  Deep fatty malignancy — not a lipoma

• Liposarcoma Diagnosis

  MRI, biopsy, and tumor board

• Liposarcoma Treatment

  Wide excision, radiotherapy, and surveillance

• Retroperitoneal Masses

  Deep abdominal tumors — imaging and resection