SEBACEOUS CYST Made by Dr Hamdy Hamed CYSTS

SEBACEOUS CYST Made by: Dr. Hamdy Hamed

CYSTS Cyst is a collection of fl uid in a sac lined by epithelium or endothelium. Word meaning of cyst is “bladder” (Greek) True Cyst False Cyst • Cyst wall is lined by epithelium or endothelium. • Fluid is usually serous or mucoid derived from the secretion of the lining • It does not have epithelial lining. • Fluid collection occurs as a result of exudation or degeneration.

Def. It is a retention cyst. It is due to blockage of the duct of sebaceous gland, causing a cystic swelling. ØIt is common in face, scalp, scrotum. ØIt is not seen in palms and soles as there are no sebaceous glands.

Structure Sebaceous cyst contains yellowish white cheesy material(consist of keratin , epithelial cells and granular debris). It is lined by only epidermal layer of squamous epithelium.

Clinical Features ØPainless swelling which is smooth, soft, non-tender, freely mobile, adherent to skin especially over the summit, fluctuant (positive Paget’s test), non trans-illuminating with punctum over the summit. ØIt moulds on finger indentation.

Punctum ØIt is present over the summit in 70% of cases when sebaceous duct opens directly into the skin which gets blocked. ØPunctum is depressed black coloured spot over the summit of the sebaceous cyst. Because (keratin) is black in colour. ØIn 30% cases sebaceous duct opens into the hair follicle and so punctum is not seen.

Clinical Features (cont. ) ØHair loss over the surface is common due to constant pressure over the roots of the hair follicles. ØUnpleasant odour of sebum content is typical. Figs: Large sebaceous cyst in the face and scalp. Note the hair loss on the surface

Complications ØInfection and abscess formation.

Complications (cont. ) ØSurface gets ulcerated leading to formation of a painful, fungating mass with discharge called as—Cock’s peculiar tumour. It is a chronic granuloma on an ulcerated surface of a sebaceous cyst.