Dermoid cyst

Dermoid cyst Definition:

  • Dermoid cyst is a benign embryonic tumor of ectodermal origin.
  • Cystic/mature teratoma: Dermoid cyst which contains tissue from all 3 germ-lines

Terminology:

  • Dermoid cyst, dermoid, epidermoid
  • Epidermoid cyst: synonym for both a dermoid cyst and an epidermal cyst.

ICD code:

  • D279

Pathogenesis:

  • Origin:  arise from tissue dispersed during embryonic development due to the entrapment of ectodermal elements along the lines of embryonic closure.
  • Composition:
    • Capsule: coarse, the surface smooth and shiny.
    • Contents: Pronounced variability of 3 germ-line derivatives with regard to their differentiation
      • Often contain hair, teeth, adnexa, bones, or fat  (contents are oily at 37 ° C, pasty at room temperature → keratinized debris can often be expressed as a cheesy mass after incision)
    • Microscopy: The following structures are randomly mixed up and embedded in loose connective tissue:
  • 70-100%
  • Epidermis, partly with nevus cell nests, hair follicles, sebum glands, smooth muscles, fat & brain tissue
  • 50-70%
  • Sweat glands, peripheral nerves, cartilage, bones, respiratory epithelium &glial tissue
  • up to 30%
  • Teeth, intestinal epithelium, thyroid tissue, ependyma, pancreatic tissue & adrenal tissue
  • up to 5%
  • Prostate, breast, retinal tissue, striated muscles, lung, kidney & thymus tissue, etc.
      • +/- Granulomatous inflammation: granulomatous inflammation with foreign body giant cells develops when the contents of the cyst penetrate the soft tissue

Dermoid cyst types as per the Localization:

  • Ovary
  • 20-30% of all ovarian tumors and 50% of benign forms therefore the most common germ cell tumors.
  • Skin
  • Especially the orbital area, the root of the nose, the ventral throat area, and the floor of the mouth
  • CNS
  • Especially cerebellopontine angle
  • Others
  • Testicles & Skull bones

Clinical manifestations:

  • Skin
  • Exists since birth and usually manifests on the skin as 1-5 cm subcutaneous cysts.
  •  Usually asymptomatic and become clinically conspicuous in the event of inflammation or rupture.
  • Ovary
  • 30% detected during pregnancy.
  • Torsion, rupture, or infection are possible.
  • Peritonitis can develop when contents of the cyst enter the abdominal cavity
  • CNS
  • Trigeminal neuralgia, facial paresis, or hearing disorders.
  • Mollaret meningitis:  cyst ruptures into the meningeal space.

Complication:

  • Malignant degeneration is possible → carcinomas of the squamous epithelium, malignant melanomas or sarcomas.

Dx:

  • CT: dermoid of CNS appear non- contrasting and hypodense → can grow around the surrounding brain tissue.
  • MRI: show a signal intensity similar to that of CSF (confused with enlarged cisterns)
  • Diffusion-weighted imaging sequence (DWI-MRI):  appear light and the liquor appear dark are used for the differential diagnosis.

Ddx:

  1. Epidermal cysts, but they usually have not been around since the birth
  2. Subcutaneous hemangiomas
  3. Gliomas and other congenital malformations of the central nervous system
  4. Other ovarian tumors

Rx:

  1. Should be excised in toto.
  2. Must be taken into account that connections to deeper-lying structures (orbit or neural structures) even with superficial localization on the skin.

Mnemonic of Cystic teratoma – Dermoid cyst 

  • “DERMOID CYST”
    • D: Diameter not more than 15 cm
    • E: Embryonic node or focus from which hair project and in which teeth and bone are present
    • R: Rokitanskys protuberance on radiology
    • M:
      1. Mucinous cystadenomas are found in association
      2. Malignant potential in a few (Epidermoid carcinoma, sarcomatous change, squamous cell carcinoma in ectodermal tissues, mammary and malignant thyroid tumors)
    • O: Ovarian tumor (Extra ovarian dermoids present in lumbosacral area, uterovesical area, parasacral and rectovaginal septum)
    • I: Immature totipotent embryonic cell is the cell of origin of this tumor.
    • D: Diffusion-weighted imaging sequence (DWI) is used for Ddx.
    • C:
      1. Contains cartilage
      2. Child (Found in pregnancy)
    • Y: Keratinized debris can often be expressed as a yellowish cheesy mass after the incision.
    • S:
      1. Sebaceous material that forms small balls
      2. Smooth surface
    • T:
      • Twists (Torsion is the most common complication)
      • Teeth or Thyroid tissue can be found
  • Author: Nakeya Dewaswala MD
  • Modified by: P.Harinath MD

MCQs:

  • Dermoid arises from?
    1. Pluripotent cell
    2. Totipotent cell
    3. Ectoderm
    4. Mesoderm
  • What is the most probable diagnosis based on the given image?

    1. Dermoid cyst
    2. Sebaceous cyst
    3. Lipoma
    4. Hemangioma

Also read:

  1. Dermoid Cyst by Shahjahan Shareef; Leila Ettefagh

Also Watch:

  • Dermoid Cyst: 5-Minute Pathology Pearls


References:

  1. Prior A, Anania P, Pacetti M, Secci F, Ravegnani M, Pavanello M, Piatelli G, Cama A, Consales A. Dermoid and Epidermoid Cysts of Scalp: Case Series of 234 Consecutive Patients. World Neurosurg. 2018 Dec;120:119-124.
  2. Sorenson EP, Powel JE, Rozzelle CJ, Tubbs RS, Loukas M. Scalp dermoids: a review of their anatomy, diagnosis, and treatment. Childs Nerv Syst. 2013 Mar;29(3):375-80.
  3. Brownstein MH, Helwig EB. Subcutaneous dermoid cysts. Arch Dermatol. 1973 Feb;107(2):237-9.
  4. Pryor SG, Lewis JE, Weaver AL, Orvidas LJ. Pediatric dermoid cysts of the head and neck. Otolaryngol Head Neck Surg. 2005 Jun;132(6):938-42.

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