Epidermoid cyst
Author:
Mikael Häggström [note 1]
Generally presents as a skin cyst. Also known as epidermal inclusion cyst (EIC) and sebaceous cyst.
Contents
Microscopic evaluation
Typical findings:[1]
- Stratified squamous epithelium with a granular layer
- Cyst wall does not contain eccrine glands, sebaceous glands or hair follicles
- Abundant keratin flakes in cyst lumen
- Often giant cell granuloma in ruptured cysts, similar to foreign body granuloma
Differential diagnosis
Mainly:
Trichilemmal cyst, containing, from external (top) to internal (bottom):[image 1][2]
- Fibrous capsule
- Small, cuboidal, dark-staining basal epithelial cells in a palisade arrangement, with no distinct intercellular bridging
- Swollen pale keratinocytes, which increase in height closer to the interior
- Solid eosinophilic-staining keratin
There is no granular cell layer (in contrast to an epidermoid cyst).Pilomatricoma: Stroma surrounding irregularly shaped islands containing basaloid cells (darkly stained, round or elongated), which abruptly or gradually transitions into ghost cells (having pale cytoplasm and a central clear area), which in turn may transition into necrosis.[image 1][3]
Further information: Skin cyst
Further workup
Look for signs of cyst rupture, which may manifest as inflammation, including granulomas and microabscesses.
Microscopic report
Example:
Scalp skin cyst, excision: Ruptured epidermoid cyst. |
Notes
- ↑ 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.
Main page
References
- ↑ 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
- ↑ Anne Elizabeth Laumann. Which histologic findings are characteristic of trichilemmal cyst (pilar cyst)?. Medscape. Updated: Jun 11, 2020,
- ↑ Punnya V Angadi (2009-06-01). Skin: Pilomatricoma. Atlas of Genetics and Cytogenetics in Oncology and Haematology.
Image sources
- ↑ 1.0 1.1 Image(s) by: Mikael Häggström, M.D. Public Domain
- Author info
- Reusing images