Skin lesions

Key points

Epidermal inclusion cysts

Most common skin cyst, occurs everywhere

Plugging of hair follicles, or traumatic implantation of follicle can result in cyst

Excise - risk of infection

Dermoid cysts

Ectodermal elements - contents can be hair follicles, sebaceous secretions

Stratifed squamous epithelial lining

Found at lines of skin/ectodermal fusion - e.g. external angular (lateral edge of eyebrow)

Excise as will enlarge

Pilomatrixoma

Benign skin tumour arising from hair follicle

Rare malignancies reported

Excise

Infantile Myofibromatosis

Benign proliferation of fibroblasts

Sollitary myofibroma or multiple lesions

Can mimic haemangiomas

Will regress spontaneously but will often be excised

Visceral involvement has poor prognosis

References

Weir CB, St.Hilaire NJ. Epidermal Inclusion Cyst. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532310/

Shareef S, Ettefagh L. Dermoid Cyst. [Updated 2023 Aug 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560573/

Zhao A, Kedarisetty S, Arriola AGP, Isaacson G. Pilomatrixoma and its Imitators. Ear, Nose & Throat Journal. 2024;103(3):183-189. doi:10.1177/01455613211044778

Han JS, Lee MW, Choi JH, Moon KC. Congenital myofibroma mimicking an infantile hemangioma in an infant. Indian J Dermatol. 2014 May;59(3):317. doi: 10.4103/0019-5154.131472. PMID: 24891688; PMCID: PMC4037978.