Skin nonmelanocytic tumor

Cysts

Dermoid cyst



Last author update: 6 December 2021
Last staff update: 24 June 2022

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PubMed Search: Dermoid cyst [title] skin

Aayushma Regmi, M.B.B.S.
Jodi Speiser, M.D.
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Cite this page: Regmi A, Speiser J. Dermoid cyst. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumornonmelanocyticdermoidcyst.html. Accessed August 11th, 2022.
Definition / general
  • Benign cutaneous developmental anomaly
  • Arises from the entrapment of ectodermal elements along the lines of embryonic closure
Essential features
  • Derived from both ectoderm (stratified squamous epithelium) and mesoderm (cutaneous adnexal structures)
  • Most commonly on the lateral aspect of the upper eyelid
  • Can be complicated by intracranial involvement
  • Total resection of the cyst, along with the adhesions and sinuses, is crucial
Terminology
  • Cystic teratoma (not true teratoma), nasal dermoid sinus cyst (when located in sinus)
ICD coding
  • ICD-10: D23.9 - other benign neoplasm of skin, unspecified
Epidemiology
Sites
Pathophysiology
Etiology
  • Mostly unknown
Clinical features
Diagnosis
  • Based on clinical features, imaging modalities and histopathological findings
Radiology description
  • CT imaging is better at delineating the changes in bony erosions
  • Magnetic resonance imaging (MRI) is the preferred means of revealing evidence of intracranial extension
  • Ultrasound (USG) demonstrates a well defined homogenous and hypoechoic cystic lesion
  • Radiological features include characteristic signal intensities, absence of perilesional edema and the presence of well defined margins to the cyst (Case Rep Neurol Med 2021;2021:9917673)
Radiology images

Contributed by Aayushma Regmi, M.B.B.S. and Jodi Speiser, M.D.
Ultrasonography of a palpable lump over the left eyebrow Ultrasonography of a palpable lump over the left eyebrow

Ultrasonography of a palpable lump over the left eyebrow



Images hosted on other servers:
Lateral dermoid cyst with characteristic hyperdense cyst wall and hypodense cyst cavity.

CT image without contrast

Prognostic factors
Case reports
Treatment
  • Complete surgical resection is the treatment of choice
  • Imaging done prior to determine the extent of underlying tissue involvement
  • Resected carefully to avoid spilling of contents intracranially
  • Recurrences have been reported in case of incomplete excision (Pediatr Dermatol 2013;30:706)
Clinical images

Contributed by Aayushma Regmi, M.B.B.S. and Jodi Speiser, M.D.
Left lateral eyebrow mass

Left lateral eyebrow mass

Left limbal mass

Left limbal mass



Images hosted on other servers:
Lower lid

Lower lid

Lateral eyebrow

Lateral eyebrow

Microscopic (histologic) description
  • Well defined wall lined by stratified squamous epithelium with mature skin appendages (hair follicles and sebaceous glands) and a lumen filled with keratin and hair shafts (Yale J Biol Med 2014;87:349, Pediatr Dermatol 2013;30:706)
  • Occasionally, smooth muscle may be present but in contrast to benign cystic teratoma, cartilage and bone has not been described (Yale J Biol Med 2014;87:349)
  • Eccrine sweat glands present in 35% of cases and apocrine glands in 15%
  • Ruptured cyst with evidence of granulomatous inflammation with giant cells, most concentrated around exposed hair follicles
  • Implantation dermoid cysts have no adnexal structures and therefore, they are easily distinguished from congenital forms on histology (BMJ Case Rep 2019;12:e228831)
Microscopic (histologic) images

Contributed by Aayushma Regmi, M.B.B.S. and Jodi Speiser, M.D.
Well defined cyst Well defined cyst

Well defined cyst

Dermoid cyst wall and contents Dermoid cyst wall and contents

Dermoid cyst wall and contents

Dermoid cyst wall and contents Dermoid cyst wall and contents

Dermoid cyst wall and contents


Lining epithelium in dermoid cyst Lining epithelium in dermoid cyst

Lining epithelium in dermoid cyst

Ruptured dermoid cyst Ruptured dermoid cyst Ruptured dermoid cyst

Ruptured dermoid cyst

Virtual slides

Images hosted on other servers:

Well defined dermoid cyst and ruptured cyst

Positive stains
Negative stains
Videos

Cutaneous dermoid cyst

Sample pathology report
  • Skin, right lower eyelid, excision:
    • Dermoid cyst
  • Skin, left shin, excision:
    • Dermoid cyst (see comment)
    • Comment: The sections show a dermal cyst lined by stratified squamous epithelium with attached sebaceous gland and hair follicle. The lumen contains loose keratin flakes and scattered hair shafts.
Differential diagnosis
  • Epidermal inclusion cyst / epidermoid cyst:
    • Smooth, dome shaped firm, skin colored nodule that is freely movable on palpation and sometimes has a small, dilated punctum
    • Lined only by stratified squamous epithelium; no adnexal structures identified
    • Lumen contains abundant keratin flakes
  • Vellus hair cyst:
    • Multiple, small, smooth, skin colored, reddish, bluish, yellowish, brown, violaceous or grayish papules
    • Mid dermal cyst containing laminated keratin and many vellus hairs
    • Epithelial lining consists of several layers of squamous epithelium, often with a granular cell layer
  • Steatocystoma:
    • Skin colored to yellowish dermal cystic papules or nodules
    • Cyst lined by stratified squamous epithelium without a granular layer with attached sebaceous gland
    • Diagnostic, corrugated eosinophilic layer lining luminal surface
  • Congenital dermoid fistula:
    • Presents at birth as a superficial fistula tract
  • Pilomatrixoma:
    • Benign tumor arising from hair matrix
    • Solid nests of basaloid cells undergoing abrupt trichilemmal type keratinization
    • Ghost cells, calcification or ossification with extramedullary hematopoiesis and frequent rupture leading to giant cell reaction
  • Encephalocele:
    • Can also be found in glabella area
    • Compressible / soft and bluish in color
    • Typically transilluminate
  • Nasal glioma:
    • Not a true neoplasm
    • Typically a firm nodule that is incompressible and red
    • Can be found in glabella area
    • Mature astrocytes, gloss and variable stromal fibrosis
    • S100 and GFAP positive
  • Pilar / trichilemmal cyst:
    • Firm and well circumscribed nodule on palpation
    • Lined by stratified squamous epithelium, which lacks granular layer
    • Contains dense eosinophilic keratin
  • Teratoma:
    • Represents true neoplasm comprised of tissues from all 3 germ layers: ectoderm, mesoderm and endoderm
Board review style question #1
A 5 year old girl with no significant past medical history presents with a slowly growing, nontender mass on the lateral third of her eyebrow. The mass is a firm, nonpulsatile, pale to flesh colored, subcutaneous nodule. Which of the following is the next best step in the management of this condition?

  1. Biopsy
  2. Excision
  3. MRI
  4. Radiograph (Xray)
Board review style answer #1
C. MRI. Before doing therapeutic excisional biopsy, proper imaging should be done due to risk of possible bony deformities, intracranial extension or intraspinal extension. Biopsy may lead to further complications worsening the infection due to rupture / spill of the content of the cyst. MRI is better than radiograph (Xray) as it evaluates the extent of intracranial and intraspinal extension, whereas Xray may detect the bone deformities.

Comment Here

Reference: Dermoid cyst
Board review style question #2

What findings in the above picture are specific to dermoid cyst?

  1. Cyst lined by stratified squamous epithelium and abundant keratin flakes
  2. Cyst lined by stratified squamous epithelium and sebaceous glands
  3. Cyst lined by stratified squamous epithelium with multiple hair shafts
  4. Cyst lined by stratified squamous epithelium with retained the granular layer
  5. Cyst lined by stratified squamous epithelium, sebaceous glands and hair follicle
Board review style answer #2
E. Dermoid cyst is lined by stratified squamous epithelium, sebaceous glands and hair follicles and is composed of abundant keratin flakes. Pilar cyst is lined by stratified squamous epithelium lacking the granular layer and contains dense laminated eosinophilic keratin. Epidermoid cyst is lined by stratified squamous epithelium with retained the granular layer and keratin flakes. Vellus hair cyst is lined by stratified squamous epithelium with multiple hair shafts. Steatocystoma is a cyst lined by stratified squamous epithelium and sebaceous glands.

Comment Here

Reference: Dermoid cyst
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