Skin cysts

Microscopic evaluation

Major initial clues are:

Whether the lining of the cyst is stratified squamous epithelium, non-stratified squamous epithelium, or absence of epithelium (pseudocysts):^[1]
Location of the cyst.^[1]

Relative incidence of cutaneous cysts.^[2]

Location	Main diagnoses^[1]
Face	Epidermoid cyst Milium Pigmented follicular cyst (men) Dermoid cyst (along embryonic fusion planes such as lateral eyebrows in infants) Verrucous cyst
Scalp	Epidermoid cyst Trichilemmal cyst Proliferating tricholemmal cyst
Trunk	Epidermoid cyst Vellus hair cyst (chest) Steatocystoma Veruccous cyst
Pelvic, anogenital	Proliferating epidermoid (infundibular) cyst
Axilla and groin	Steatocystoma Epidermoid cyst
Preauricular	Ear pit cyst Epidermoid cyst
Upper gluteal cleft and sacrococcygeal area	Pilonidal cyst

Location	Main diagnoses^[1]
Face	Hidrocystoma Eccrine at lower eyelid and cheek Apocrine at eyelid margin
Suprasternal notch	Bronchogenic cyst (infants)
Midline anterior neck	Thyroglossal duct cyst
Lateral neck, preauricular, mandibular	Brachial cleft cyst (teenagers and young adults)
Lower extremities	Cutaneous ciliated cyst (young women)
Labia majora	Ciliated cyst of the vulva
Ventral glans and penile shaft	Median raphe cyst
Umbilical or periumbilical	Omphalomesenteric duct cyst

Location	Main diagnoses^[1]
Oral mucosa	Mucocele (lower labial)
Dorsal aspect of distal phalanx of finger or toe	Digital mucous cyst/pseudocyst
Wrist	Ganglion
Scaphoid fossa of the ear	Pseudocyst of the auricle (adult men)
Sites of surgical trauma	Cutaneous metaplastic synovial cyst/pseudocyst

Typical findings:^[3]

↑ For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 page 1917 in: Bolognia, Jean (2018) (in de). Dermatology . Philadelphia, Pa: Elsevier. ISBN 978-0-7020-6342-8. OCLC 1011508489.
↑ Pakistan: Kamyab, Kambiz; Kianfar, Nika; Dasdar, Shayan; Salehpour, Zahra; Nasimi, Maryam (2020). "Cutaneous cysts: a clinicopathologic analysis of 2,438 cases ". International Journal of Dermatology. doi:10.1111/ijd.14808. ISSN 0011-9059.
↑ V. Claire Vaughan, M.D., Joshua Wisell, M.D.. Skin nonmelanocytic tumor - Cysts - Epidermal (epidermoid) type. pathology Outlines. Topic Completed: 9 May 2019. Revised: 13 December 2019