Uterus - Atypical polypoid adenomyoma

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Uterus

Epithelial tumors-benign

Atypical polypoid adenomyoma

Reviewer: Jamie Shutter, MD, University of South Florida (see Reviewers page)

Revised: 25 August 2011, last major update June 2010

Definition

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● Biphasic polypoid lesion consisting of a myofibroblastic stromal component and an endometrial intraepithelial neoplasm typically with squamous metaplasia

Terminology

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● Also called APA, atypical polypoid adenomyofibroma

Epidemiology

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● Uncommon

● Mean age 40 years, range 21-73 years (Am J Surg Pathol 1996;20:1)

● May occur in women with Turner’s syndrome (Int J Gynecol Pathol 1987;6:104)

Sites

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● Usually lower uterine segment (Am J Clin Pathol 1986;86:139)

Clinical features

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● May persist or recur, but does not metastasize

● Patients have increased risk for subsequent carcinoma

Case reports

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● 53 year old woman with pelvic pain (Arch Pathol Lab Med 2002; 126:864)

Treatment

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● Hysterectomy if peri/postmenopausal

● More conservative management with complete removal of the tumor and close follow up may be considered for women desiring to preserve their fertility (Fertil Steril 2008;89:456e9)

Gross description (Macroscopy)

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● Resembles endometrial polyp but often sessile with a broader base

● Single, well-circumscribed, polypoid mass; often in lower uterine segment; usually confined to endometrium with pushing margin; remaining endometrium is often unremarkable

Gross images

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Figure 1

Micro description (Histopathology)

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● Biphasic tumor consisting of an endometrial intraepithelial neoplasm (complex architecture, varying atypia up to severe) separated by fascicles of bland smooth muscle and fibrous stroma (no endometrial type stroma is present)

● Squamous morules are usually present, may have central necrosis

● Some cases have more prominent fibrous appearance; may be called atypical polypoid adenofibroma

● Minimal mitotic activity (<3 per 10 HPF); no desmoplasia

● May coexist with EIN / complex atypical hyperplasia (Diagn Cytopathol 2009 Nov 30 [Epub ahead of print]) or well-differentiated endometrioid adenocarcinoma

Micro images

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Whole mount

Atypical complex glandular hyperplasia,

smooth muscle stroma and squamous morules

Endometrial glands that vary in size There is architectural irregularity of

and shape are separated by swirling proliferative glands. Intervening stroma is made

fascicles of cytologically benign, up of interlacing fascicles of smooth muscle.

cellular smooth muscle. The upper

portion consists of uninvolved surface

endometrium. The junction between

the adenomyoma and adjacent

endometrium is well demarcated (pushing).

Part of the epithelial component

consists of large benign morules.

Figures 2-4 Ki-67

Positive stains

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● Stroma: HHF35, alpha-smooth muscle actin, vimentin, trichrome; variable desmin (Histopathology 1995;27:35)

● Variable Ki-67 proliferative activity, but usually low

Negative stains

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● CD10 (may be weak/focal, Hum Pathol 2008;39:1446)

Cytology description

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● Abnormal proliferation of epithelium and stromal cells of smooth muscle origin (Diagn Cytopathol 2009;38:527)

Electron microscopy descriptions

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● Smooth muscle cells (Pathology 1985;17:522)

Differential Diagnosis

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● Carcinosarcoma: also called MMMT, sarcomatoid carcinoma; older women, stroma also malignant, diffuse atypia, increased mitotic activity

● Endometrioid adenocarcinoma, invasive into myometrium: older women, grossly invasive, large tumor with hemorrhage and necrosis, definite invasion with desmoplasia

Additional references

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● Mod Pathol 2000;13:328, Mod Pathol 2000;13:309

End of Uterus > Epithelial tumors-benign > Atypical polypoid adenomyoma

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