Mesenchymal / mixed epithelial & mesenchymal tumors


Topic Completed: 1 August 2016

Minor changes: 17 May 2021

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PubMed Search: Adenomyoma of endocervical type

Leonel Maldonado Gonzalez, M.D.
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Cite this page: Maldonado L. Adenomyoma . PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cervixadenomyoma.html. Accessed January 21st, 2022.
Definition / general
  • Rare and frequently underdiagnosed biphasic tumor composed of benign endocervical glands and smooth muscle typically located in the endocervix, first described in 1996 (Mod Pathol 1996;9:220)
Essential features
  • Usually an incidental finding in women of reproductive or postmenopausal age (mean age 40 years)
  • Presents as a polyp or mass protruding through the external cervical os, resulting in abnormal bleeding or vaginal discharge, causing concern for malignancy
  • Well circumscribed neoplasm composed of irregularly shaped, benign endocervical-type glands, often in a lobular arrangement, admixed with myomatous smooth muscle
  • Benign with an excellent prognosis if completely removed
ICD coding
  • Suggested ICD-10 Code(s):
    • D26.0: other benign neoplasm of cervix uteri
    • N84.1: polyp of cervix uteri
    • N88.8: other specified noninflammatory disorders of cervix uteri
    • N88.9: non-inflammatory disorder of cervix uteri, unspecified
  • Women of reproductive or post-menopausal age (mean age 40 years)
  • Arises from endocervix
  • Endometrioid type adenomyomas (not described here) usually originate from the endometrium, but could also arise from the endocervix
Clinical features
  • Usually an incidental finding
  • May be asymptomatic; usually discovered incidentally during regular gynecologic examination
  • May present as a polyp or 'fibroid' protruding through the external cervical os, or may result in abnormal bleeding or vaginal discharge, causing concern for malignancy
  • Less commonly, there is cervical enlargement by a mural mass without mucosal involvement
Radiology images

Contributed by Leonel Maldonado, M.D.
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MRI of the pelvis

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Sagittal T2

Prognostic factors
  • Excellent prognosis if completely removed by local excision or simple hysterectomy
Case reports
  • Local excision or simple hysterectomy
Clinical images

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Bulging tumor from anterior cervix (fig 1)

Gross description
  • Usually well circumscribed, unencapsulated and solitary; may be polypoid if submucosal
  • White to gray to tan cut surface
  • The epithelial component may be seen as mucin filled cysts, while the mesenchymal areas have a firm consistency with a whorled cut surface
Gross images

Contributed by Leonel Maldonado, M.D.
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Endocervical mural tumor

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Polypoid mass from uterine cervical wall

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Polypoid mass with numerous cysts

Microscopic (histologic) description
  • Well circumscribed, unencapsulated neoplasm composed of irregularly shaped benign endocervical type glands, often in a lobular arrangement, admixed with myomatous smooth muscle
  • Endocervical cells have basal nucleus with abundant pale cytoplasm and may show tubal or tuboendometrioid metaplasia
  • The smooth muscle component forms variably sized and shaped fascicles embedded in a collagenous background; cells have bland cytologic features with eosinophilic cytoplasm and spindled cigar shaped nuclei
  • Mitotic activity is absent in both epithelial and smooth muscle components
  • No desmoplastic response is evident
Microscopic (histologic) images

Contributed by Leonel Maldonado, M.D.
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Endocervical type glands surrounded by smooth muscle

Cytology description
  • Endocervical polyps in general have no specific cytological pattern, except for the rare finding of a fragment of a polyp in smears which, when present, display smooth borders lined by columnar cells, pale intermediate zones and dark inner cores of numerous small, dark stromal cells
  • Otherwise, cervical smears present considerable numbers of benign endocervical cells, shedding in large sheets or forming glands
  • Spindled smooth muscle cells present as cohesive fragments with frayed edges revealing spindle cells with bipolar cytoplasmic processes
  • Metaplastic and reactive endocervical cells in an inflammatory background can be present as well
Cytology images

Contributed by Leonel Maldonado, M.D.
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Fragment of endocervical polyp

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Benign endocervical cells

Positive stains
Negative stains
Differential diagnosis
  • Adenoma malignum (minimal deviation adenocarcinoma): glands lined by cells with abundant cytoplasm reminiscent of pyloric-type epithelium (HIK1083 and cytoplasmic CEA positive), with at least focal malignant cytologic features and rarely identified mitotic figures; lymphovascular and perineural invasion
  • Lobular endocervical glandular hyperplasia: lobular arrangement of hyperplastic small / medium sized, rounded endocervical glands lined mostly by single layer of columnar, mucin rich epithelium; lacks a prominent component of smooth muscle
  • Mesonephric adenomyoma: lobular arrangement of dilated gland of non-mucinous type lined by simple cuboidal epithelium with scant cytoplasm and luminal eosinophilic colloid-like material; abundant stromal smooth muscle; glands are ER / PR negative and vimentin / CD10 positive (Histopathology 2015;66:420)
  • Tunnel clusters: lobular proliferation of often dilated endocervical glands (clefts) with side channels growing out of them; benign nuclear features with minimal atypia and no smooth muscle component
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