Ovary

Germ cell tumors

Monodermal teratomas

Monodermal cystic teratoma



Last author update: 22 May 2024
Last staff update: 23 May 2024

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PubMed Search: Monodermal cystic teratoma

Azin Mashayekhi, M.D., M.B.A.
Gulisa Turashvili, M.D., Ph.D.
Page views in 2024 to date: 3,242
Cite this page: Mashayekhi A, Turashvili G. Monodermal cystic teratoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarymonodermalcysticteratoma.html. Accessed December 19th, 2024.
Definition / general
  • Benign cystic tumor comprising mature tissues derived from a single germ layer (ectoderm or endoderm), except for struma ovarii, carcinoid and neuroectodermal type tumors (malignant tumors of central neuroectodermal derivation)
Essential features
  • Cystic tumor lined by benign keratinizing squamous epithelium or neuroectodermal tissues
  • May contain pituitary type adenomas
  • Benign with excellent prognosis
ICD coding
  • ICD-O: 9080/0 - cystic teratoma NOS
  • ICD-11: 2F32.0 - cystic teratoma
Epidemiology
  • Monodermal teratomas are rare (Pediatr Dev Pathol 2015;18:341)
  • Neuroectodermal cysts have been reported in children and young women
  • Epidermoid cysts occur across a wide age range
Sites
  • Ovary
Pathophysiology
  • Unknown
Etiology
  • Unknown
Clinical features
Diagnosis
  • Histologic examination
Laboratory
Radiology description
  • Wide spectrum of radiologic presentation ranging from a purely cystic to a complex cystic mass with a considerable solid component
Radiology images

Contributed by Azin Mashayekhi, M.D., M.B.A. and Gulisa Turashvili, M.D., Ph.D.
MRI of pelvis MRI of pelvis MRI of pelvis

Magnetic resonance imaging (MRI) of pelvis

Prognostic factors
  • Benign with excellent prognosis
Case reports
Treatment
Gross description
Gross images

Contributed by Azin Mashayekhi, M.D., M.B.A. and Gulisa Turashvili, M.D., Ph.D.
Cystic lesion

Cystic lesion

Frozen section description
  • Rarely performed but usually shows a cystic lesion lined by benign squamous epithelium or neuroectodermal tissues
Microscopic (histologic) description
  • Neuroectodermal cyst
    • Lined by ependymal cells
    • May show choroid plexus-like epithelium along the cyst lining
    • Astrocytes, oligodendrocytes, microglia and ganglion cells may be present adjacent to the cyst lining (Histopathology 1994;24:477)
  • Epidermoid cyst
    • Lined by mature, often keratinizing, stratified squamous epithelium
    • Surrounded by a rim of collagenous stroma containing fibroblasts
    • Keratinaceous debris fills the cyst lumen, with no evidence of hair or a Rokitansky tubercle (Int J Gynecol Pathol 1996;15:69)
  • Rarely, cysts are lined by respiratory type epithelium (Cancer 1979;43:383)
  • Lactotroph adenoma
  • Corticotroph adenoma
Microscopic (histologic) images

Contributed by Azin Mashayekhi, M.D., M.B.A. and Gulisa Turashvili, M.D., Ph.D.
Cystic lesion Cystic lesion

Cystic lesion

Cystic lesion

Cystic lesion

Intracystic proliferation Intracystic proliferation

Intracystic proliferation

GFAP

GFAP

Positive stains
Sample pathology report
  • Ovary, right, cystectomy:
    • Epidermoid cyst (monodermal cystic teratoma)
Differential diagnosis
  • Mature teratoma:
    • Mature tissue representing at least 2 germ layers (BMC Cancer 2019;19:217)
    • Malignant transformation occurs rarely (most commonly squamous cell carcinoma)
  • Immature teratoma:
    • Malignant germ cell tumor (Obstet Gynecol 2006;107:1075)
    • Contains variable amounts of immature tissue (typically immature neuroepithelium comprising primitive appearing cells with scant cytoplasm, hyperchromatic nuclei and frequent mitoses)
  • Steroid cell tumor:
    • Pituitary type adenomas may be mistaken for steroid cell tumors with eosinophilic (lipid poor) cells
    • Association with ependymal lined neuroectodermal cyst as well as prolactin expression in lactotroph adenoma and ACTH expression in corticotroph adenoma along with negative sex cord stromal markers (inhibin, calretinin, SF1) are helpful clues
Board review style question #1

The image above is a representative section of an ovarian cyst from a 40 year old woman. What is the most likely diagnosis?

  1. Epidermoid cyst
  2. Immature cystic teratoma
  3. Monodermal cystic teratoma with respiratory epithelium
  4. Struma ovarii
Board review style answer #1
A. Epidermoid cyst. This ovarian cyst is lined by benign keratinizing squamous epithelium, consistent with epidermoid cyst. Answer D is incorrect because struma ovarii is exclusively composed of benign thyroid tissue. Answer C is incorrect because some monodermal cystic teratomas are lined by respiratory epithelium. Answer B is incorrect because immature cystic teratoma exhibits immature neuroepithelium in addition to endodermal, mesodermal and ectodermal elements.

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Reference: Monodermal cystic teratoma
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