Epidermal inclusion cyst

Case contributed by Dr Muhammad Yousaf


Slowly growing swelling on left arm for last 7 years

Patient Data

Age: 40 years
Gender: Male

Left arm swelling


A rounded, firm, non-tender, fluctuant swelling on flexor surface of the left arm.


High-resolution ultrasound of forearm swelling shows a well-circumscribed hypoechoic ovoid lesion with dermal attachment, showing increased through transmission, multiple linear anechoic areas and few echogenic strands. No internal vascularity was appreciated on optimal color settings. No calcifications or any signs of cyst leak.

Case Discussion

Above mentioned findings are most likely suggesting an epidermal inclusion cyst.

Epidermal inclusion cysts are more common in men, frequently occur at the sites of inflamed hair follicles and can be seen in conjunction with acne.

Epidermal inclusion cysts are slow growing benign cystic lesions and can be seen anywhere on the body. Other synonyms for these cysts include epidermoid cyst, inclusion cyst, keratin cyst or sebaceous cysts. The term sebaceous cyst is a misnomer; however it is often used interchangeably.

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