Mixed epithelial and mesenchymal tumors

Atypical polypoid adenomyoma

Editorial Board Member: Ricardo R. Lastra, M.D.
Deputy Editor-in-Chief: Jennifer A. Bennett, M.D.
Stephanie L. Skala, M.D.

Last author update: 26 April 2022
Last staff update: 26 April 2022

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PubMed Search: Atypical polypoid adenomyoma

Stephanie L. Skala, M.D.
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Cite this page: Skala SL. Atypical polypoid adenomyoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/uterusapa.html. Accessed May 29th, 2023.
Definition / general
  • Polypoid lesion composed of atypical, architecturally complex endometrial glands within benign myomatous / fibromyomatous stroma (Am J Surg Pathol 2015;39:1148)
Essential features
  • Biphasic neoplasm composed of crowded atypical endometrial glands (with or without squamous morules) in myomatous / fibromyomatous stroma
  • Stroma typically positive for SATB2, in contrast to most examples of myoinvasive carcinoma
  • Risk of recurrence or concurrent or subsequent endometrial endometrioid carcinoma
  • Atypical polypoid adenomyofibroma
ICD coding
  • ICD-11: XH7ZB1 - atypical polypoid adenomyoma
  • Usually diagnosed in women of reproductive age; range of 25 - 73 years (Am J Surg Pathol 1996;20:1)
  • Associated with obesity, infertility, nulliparity
  • Lower uterine segment > uterine corpus
  • Unknown
Clinical features
  • Based on histologic features
Radiology description
  • T2 weighted MRI images: slightly hyperintense polypoid mass mixed with markedly hyperintense foci corresponding to endometrial glands
  • T1 weighted MRI images: isointense with myometrium, occasional hyperintense cystic foci
  • Solid portions, other than cystic foci, show contrast enhancement in the arterial phase and washout or plateau pattern in the late phase
  • Reference: J Comput Assist Tomogr 2015;39:32
Prognostic factors
Case reports
  • 29 year old woman with low grade endometrioid adenocarcinoma arising from atypical polypoid adenomyoma; diagnosed in early pregnancy and managed conservatively (Gynecol Oncol Rep 2019;28:101)
  • 35 year old woman with atypical polypoid adenomyoma treated by hysteroscopy with photodynamic diagnosis using 5-aminolevulinic acid (Photodiagnosis Photodyn Ther 2019;27:295)
  • 36 year old woman with endometrioid adenocarcinoma developing 8 years after conservative management for atypical polypoid adenomyoma (Gynecol Oncol Case Rep 2014;8:21)
  • 45 year old woman with atypical polypoid adenomyoma treated with local resection (Pathologica 2020;112:214)
Gross description
Gross images

Images hosted on other servers:
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Polypoid mass

Microscopic (histologic) description
  • Biphasic tumor:
    • Endometrioid glands, usually with complex architecture and sometimes with cytologic atypia
    • Glandular component often shows lobulated architecture
    • Benign fibromyomatous stroma, rarely with myxoid change
  • Squamous morular metaplasia is frequently seen and may show central necrosis
  • Well circumscribed or slightly irregular margin
  • Reference: Am J Surg Pathol 2015;39:1148
Microscopic (histologic) images

Contributed by Stephanie L. Skala, M.D.

Lobulated architecture

Crowded glands and muscular stroma

Smooth muscle underlying surface endometrium

Crowded glands and muscle bundles

Squamous morule with central necrosis

Haphazard gland arrangement

Myxoid spindled stroma

Stromal SATB2 positivity

Virtual slides

Images hosted on other servers:
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Endometrial curettings showing APA

Missing Image

APA fragment with lobulated architecture

Positive stains
Negative stains
Molecular / cytogenetics description
Sample pathology report
  • Uterus, total hysterectomy:
    • Atypical polypoid adenomyoma
Differential diagnosis
Board review style question #1

The tumor above is seen in endometrial curettings from a 36 year old patient. Which of the following statements is true?

  1. Atypical polypoid adenomyoma can progress to endometrioid carcinoma
  2. Atypical polypoid adenomyoma is associated with TP53 mutations
  3. Comedonecrosis of squamous morules implies poor prognosis
  4. Hysterectomy is always the first line treatment for atypical polypoid adenomyoma
  5. Progestin typically leads to regression of atypical polypoid adenomyoma
Board review style answer #1
A. Atypical polypoid adenomyoma can progress to endometrioid carcinoma

Comment here

Reference: Atypical polypoid adenomyoma
Board review style question #2
Patients with atypical polypoid adenomyoma that are diagnosed on endometrial biopsy are at an increased risk for which of the following?

  1. Carcinosarcoma
  2. Clear cell carcinoma
  3. Endometrioid carcinoma
  4. Endometriosis
  5. Serous carcinoma
Board review style answer #2
C. Endometrioid carcinoma

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Reference: Atypical polypoid adenomyoma
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