Adenosarcoma

Uterus
Stromal tumors
Adenosarcoma

Author: Sanjay Logani, M.D. (see Authors page)

Revised: 26 January 2017, last major update June 2010

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed search: uterine adenosarcoma

Table of Contents

Cite this page: Adenosarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uterusadenosarcoma.html. Accessed July 16th, 2017.

Definition / general

A rare, low grade, biphasic, malignant mixed müllerian tumor (MMMT), usually in elderly, with benign epithelial and sarcomatous mesenchymal components
First described in 1974 (Cancer 1974;34:1138)
References: Mod Pathol 2000;13:328, Adv Anat Pathol 2010;17:122

Terminology

Also called müllerian adenosarcoma

Epidemiology

5% - 7% of uterine sarcomas
Median age 58 years, range 13 - 89 years (Hum Pathol 1990;21:363)

Sites

Usually uterus or cervix, also elsewhere in gynecologic tract
Rare cases reported involving the intestine

Etiology

Rosai considers these tumors to be a variant of endometrial stromal sarcoma with the capacity to form glands, including sex cord-like differentiation

Clinical features

Often presents with abnormal vaginal bleeding, enlarged uterus and tissue protruding from external os
May occasionally present as low grade endometrial polyps, with subtle low grade sarcomatous features (J Clin Pathol 2006;59:801) or at biopsy with no sarcomatous features (diagnosis requires re-excision)
Usually stage IA or IB (Am J Surg Pathol 2009;33:278)
Younger patients are often misdiagnosed (Aust N Z J Obstet Gynaecol 2008;48:596)

Prognostic factors

Poor prognostic factors: high grade sarcomatous overgrowth, myometrial invasion or high grade tumor

Case reports

42 year old woman with uterine mass post tamoxifen for breast cancer (Case contributed by Dr. Najla Fakhruddin)
45 year old woman with lymphovascular emboli (Cases J 2009;2:7515)

Treatment

Hysterectomy is usually curative
May recur in pelvis or vagina; rarely metastasizes

Gross description

Bulky, polypoid and multicystic neoplasm arising from endometrium and filling endometrial cavity
May be fleshy
Mean 6 cm, but up to 20 cm
Less hemorrhage and necrosis than MMMT

Gross images

Images hosted on PathOut server:

Large polypoid mass fills entire endometrial cavity (fig 1E)

Microscopic (histologic) description

Epithelial and stromal elements with stromal hypercellularity
Epithelial component appears benign; glands are usually large and dilated with periglandular stromal cuffing, 80% have cambium layer (stromal condensation) beneath surface epithelium and adjacent to glands (most characteristic histologic feature); mitotic activity and cytologic atypia are more common in this zone
Epithelium is usually endometrioid but also ciliated, mucinous and even squamous
Stroma has polypoid or leaf-like projections into glandular lumina, resembling phyllodes tumor of breast
Stromal elements have mild or occasionally moderate atypia; resemble low grade endometrial stromal sarcoma but less bizarre and less undifferentiated
33% have sarcomatous overgrowth
25% - 47% are myoinvasive
20% have multinucleated giant cells and heterologous elements (skeletal muscle)
May also have extensive stromal fibrosis
Occasionally sex cord like elements (Am J Clin Pathol 1989;91:664)
Usually 1+ mitotic figure/10 HPF in stromal cells

Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Weijie Li, MD:

Fig 1: 2×; Figs 2 & 3: 10×; Fig 4: 20×; Fig 5: 40×

Images hosted on other servers:

Dilated glands surrounded by cuff of stomal cells (fig 1F)

Cambium layer

Benign epithelial cells and
malignant stromal cells
with mitotic figures

Epithelial glands
show prolif-
eration, but no
obvious atypia

Cambium layer with marked atypia

Malignant stromal cells

Cytology images

Images hosted on other servers:

Denuded malignant cells with variable sizes

Dense clusters of polymorphic tumor cells

Long oval, hyperchromatic nuclei with 1+ nucleoli (Pap)

Partly denuded tumor cells with fragile cytoplasm

Tumor cells have variable sizes

Positive stains

Mesenchymal component, in areas without sarcomatous overgrowth:

ER, PR, WT1 and CD10 (Am J Surg Pathol 2008;32:1013)
Variable muscle markers, keratin (epithelial component) and androgen receptor

Electron microscopy description

Features of proliferative endometrium; stroma resembles endometrial stromal sarcoma or mixed müllerian tumor (Am J Clin Pathol 1979;71:112)

Differential diagnosis

Adenofibroma: may be extremely difficult to distinguish on a curettage specimen; no hypercellular stroma, no cambium layer, low mitotic index (< 2/10 HPF) and at most mild stromal nuclear atypia
Adenomyomatous polyp: attenuated surface endometrium on 3 sides; cystic change; large, thick walled blood vessels, no stromal hypercellularity, no cuffing and no atypia
Carcinosarcoma: malignant epithelial (at least focally) and sarcomatous elements
Embryonal rhabdomyosarcoma (children): evidence of skeletal muscle differentiation (histology, immunohistochemistry or EM)
Endometrial stromal sarcoma: often intravascular growth, tongue-like infiltration and arborizing vessels; may have glands, but they are smaller and not dilated; no periglandular stromal condensation, no intraluminal polypoid protrusions
Endometriosis, polypoid: resembles adenosarcoma particularly when occurring in cervix or peritoneum