Sebaceous cyst does not occur in the ...................................
• Epidermoid cyst results from proliferation of epidermal cells within a circumscribed space of dermis (which had got implanted within the dermis)
• Sebaceous cyst is a misnomer as the cysts are not of sebaceous origin and the white creamy material filled within is not sebum, but is keratin (desquamated epithelial cells)
• Type of retention cyst (secretions are pent up in a gland owing to blockage of the duct)
Pathology
• Cyst wall consist of a layer of epidermis oriented with the basal layer superficial and more matured layers are deep.
• Desquamated cells (keratin) collect in the centre and form creamy substance of the cyst.
Clinical Features
• Usually asymptomatic, unless get infected or inflamed and become painful
• Firm, round, flesh colored to yellow or white subcutaneous nodules of variable size.
• Central punctum may teether the cyst to the overlying epidermis, from which the white creamy material can be expressed.
• Rarely malignancies (BCC, SCC) can develop in epidermoid cyst.
• No punctum in scrotal and scalp sebaceous cyst.
Treatment
• Excision with the wall is treatment of choice.
• Infected cyst: Incision and drainage (After resolution of the abscess, cyst wall must be excised to prevent recurrence)
Scalp
Scrotum
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Sole