Uterus

Stromal tumors

Endometrial stromal nodule



Minor changes: 23 September 2021

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PubMed search: endometrial stromal nodule uterus

Devi Jeyachandran, M.D.
Mohamed Mokhtar Desouki, M.D., Ph.D.
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Cite this page: Jeyachandran D, Desouki MM. Endometrial stromal nodule. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/uterusstromalnodule.html. Accessed October 21st, 2021.
Definition / general
  • Benign tumor composed of cells reminiscent of proliferative phase endometrial stroma with absent or minimal myometrial invasion (< 3 mm and < 3 protrusions) and lacking vascular invasion
Essential features
  • Benign tumor composed of cells reminiscent of proliferative phase endometrial stroma with absent or minimal myometrial invasion (< 3 mm and < 3 protrusions) and lacking vascular invasion
  • Can be cystic, have necrosis and hemorrhage
  • Excellent prognosis if completely excised
ICD coding
  • ICD-10: D26.1 - other benign neoplasm of corpus uteri (endometrial - stromal)
Epidemiology
  • Rare tumor
  • Occurs at any age (mostly in the fifth and sixth decades)
  • Associated with hypoestrogenism, tamoxifen therapy, radiation
Sites
  • Corpus > cervix > ovary
Pathophysiology
  • Unknown
Etiology
  • Unknown
Clinical features
  • Usually asymptomatic / incidental
  • Abnormal vaginal bleeding
  • Pelvic mass
Diagnosis
Radiology description
Prognostic factors
  • Excellent prognosis if completely excised (hysterectomy)
Case reports
Treatment
  • Hysterectomy if fertility is complete or not desired
  • If fertility preservation is desired, conservative excision followed by hysteroscopy to monitor for regrowth
  • Conservative excision may be adequate but usually limits ability to sample margins
Gross description
  • Well circumscribed, nonencapsulated, soft, fleshy yellow, solitary lesion with size ranging from 1 - 12 cm
  • Tumors usually grow in an expansile, noninfiltrating pattern with a smooth margin
  • Rarely, can show some irregularities but no intravascular component
  • Usually located in the endometrial cavity (polypoid mass) but can also be seen in myometrium
  • Can be cystic
  • Can have necrosis and hemorrhage
Gross images

Contributed by Devi Jeyachandran, M.D.

Polypoid uterine tumor



Images hosted on other servers:

Uterine tumor

Frozen section description
  • If sent for frozen, it may be difficult to differentiate with other spindle cell lesions
    • Can be reported as spindle cell proliferation; final diagnosis deferred to permanent
Microscopic (histologic) description
  • Monotonous proliferations of bland endometrial stromal cells
  • Expansive growth pattern (not infiltrating) at the margin
  • Infiltration, if present, should be < 3 mm and < 3 protrusions
  • Usually prominent proliferative type arterioles and can sometimes show hyalinized walls
  • Collagen bands, plaques, infarct-like necrosis, hemorrhage and degenerative changes (cholesterol clefts, myxoid change and histiocytes) can be present
  • Large, thick blood vessels are uncommon; if present, usually are seen at tumor - myometrium interface
  • May have sex cord-like differentiation, epithelioid morphology, rhabdoid features, clear cells, granular cytoplasm, pseudopapillary, glandular element, fat cells, multinucleated giant cells, bizarre cells, myxoid change
  • No angiolymphatic invasion should be present
  • Mitotic activity is usually < 10 per 10 high power fields
  • Note: foci of smooth muscle metaplasia within the tumor should not be interpreted as myometrial invasion at the edge of the tumor
Microscopic (histologic) images

Contributed by Devi Jeyachandran, M.D.

Bland stromal cells

Expansive growth

Proliferative type arterioles

Bland stromal cells

CD10 expression

ER expression


PR expression

WT1 expression

SMA expression

AE1 / AE3 expression

Desmin expression

Positive stains
Negative stains
  • Desmin, h-caldesmon (but can be positive if smooth muscle or sex cord-like differentiation is present)
  • CD34 (rarely positive)
Molecular / cytogenetics description
  • t(7;17) most common JAZF1-SUZ12
  • PHF1 gene rearrangements (especially if sex cord-like areas are present)
Sample pathology report
  • Uterus, cervix, fallopian tubes and ovaries, total hysterectomy and bilateral salpingo-oophorectomy:
    • Endometrial stromal nodule (see comment)
    • Comment: The mass is extensively sampled and the microscopic examination shows bland spindle cell proliferation resembling endometrial stroma with rare mitosis and proliferative type arterioles. Given the morphology and noninfiltrative growth pattern along with strong CD10 positivity, the above diagnosis is rendered.
  • Endometrium, curettage:
    • Spindle cell proliferation, final classification deferred to resection specimen (see comment)
    • Comment: The biopsy shows bland spindle cell proliferation resembling endometrial stroma with rare mitosis and proliferative type arterioles. These features favor a low grade endometrial stromal tumor but distinction between an endometrial stromal nodule versus low grade endometrial stromal sarcoma cannot be made on a limited sampling.
Differential diagnosis
Board review style question #1
The diagnosis of endometrial stromal nodule versus low grade endometrial stromal sarcoma is based on

  1. Depth of invasion (superficial versus deep)
  2. Presence and absence of molecular alteration
  3. Size and number of invasive focus
  4. Size of the tumor
Board review style answer #1
C. Size and number of invasive focus

Comment Here

Reference: Endometrial stromal nodule
Board review style question #2

A 56 year old woman presents with abnormal uterine bleeding and a polypoid mass in the uterus. The tumor is characterized by well circumscribed bland spindled cells with delicate vasculature. No mitoses, atypia or necrosis were identified. No myometrial invasion is identified. The tumor cells are strongly and diffusely positive for CD10, ER and SMA and negative for desmin, caldesmon and MelanA. What type of tumor does this likely represent?

  1. Endometrial polyp
  2. Endometrial stromal nodule
  3. Endometrial stromal sarcoma, low grade
  4. Gland poor adenomyosis
  5. Leiomyoma
Board review style answer #2
B. Endometrial stromal nodule

Comment Here

Reference: Endometrial stromal nodule
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