Chronic Endometritis

Slide 1 · Chronic Endometritis

Histopathology • etiologic associations • clinicopathologic diagnosis

With acute endometritis as the principal inflammatory comparator

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning outcomes

Locate the endometrial glands and stroma within the uterine corpus.

Distinguish acute from chronic endometrial inflammation.

Identify the etiologic settings associated with chronic endometritis.

Apply the stromal plasma-cell criterion with diagnostic caution.

Integrate microscopic findings with clinical presentation.

Slide 3 · Uterine corpus: The anatomic substrate

Uterine lumen

Endometrium: Glands in stroma

Myometrium: Smooth muscle

Original anatomical schematic; Layers and glands are simplified, not a histologic specimen.

Slide 4 · Glands and stroma: Two diagnostic compartments

Gland

Stroma

Original schematic — cell distribution is illustrative, not diagnostic evidence.

Slide 5 · Cycle-dependent endometrial remodeling

Menstrual shedding

Estrogen-driven proliferation

Progesterone-driven secretion

Stromal breakdown

Slide 6 · Normal histologic cycle: What changes?

Phase

Glands

Stroma

Proliferative

Straight; Epithelial mitoses

Cellular; Actively proliferating

Early secretory

Subnuclear vacuoles

Begins functional differentiation

Late secretory

Tortuous / serrated

Edema and predecidual change

Menstrual

Fragmentation

Breakdown with hemorrhage

Slide 7 · Physiologic leukocytes are not sufficient

Late secretory endometrium may contain sparse neutrophils and lymphocytes.

These findings must be interpreted in their menstrual-cycle context.

Stromal plasma cells as the critical chronic-endometritis finding.

Do not diagnose chronic endometritis from lymphocytes alone.

Slide 8 · Why uterine infection is comparatively uncommon

Endocervical barrier

Limited ascent of organisms

Endometrial infection is unusual

Chronic inflammation of the cervix is common; In the endometrium it is more concerning.

Slide 9 · Inflammation: Acute versus chronic

Acute pattern

Usually occurs after childbirth or miscarriage

Retained gestational products often predispose

Predominant acute inflammatory response

Chronic pattern

Occurs with several persistent clinical settings

Stromal plasma cells establish the diagnosis

Symptoms may be subtle or absent

Slide 10 · Acute endometritis: Clinical setting

An uncommon bacterial infection after delivery or miscarriage.

Retained products of conception are a usual predisposing factor.

Group A hemolytic streptococci, staphylococci and other bacteria.

Important as a comparator—not the same entity as chronic endometritis.

Slide 11 · Acute endometritis: Underlying sequence

Delivery or miscarriage

Retained gestational tissue

Bacterial infection

Acute stromal inflammation

Slide 12 · Acute endometritis: Microscopic emphasis

The response occurs mainly in the endometrial stroma.

Inflammation is nonspecific; Correlate with recent pregnancy events.

Acute inflammatory cells alone do not establish chronic endometritis.

Assess whether retained gestational tissue is also represented.

Slide 13 · Acute endometritis: Treatment principle

Remove retained gestational products when present

Administer appropriate antibiotics

Infection generally clears promptly

Curettage plus antibiotic therapy in the typical retained-products setting.

Slide 14 · Chronic endometritis: Diagnostic definition

An inflammatory disorder of the endometrial lining.

The histologic diagnosis depends on stromal plasma cells.

A clinical syndrome alone is not equivalent to tissue-confirmed disease.

Identify clinical associations without assuming a single pathogen.

Slide 15 · The principal associations

Pelvic inflammatory disease

Retained gestational tissue

Intrauterine contraceptive device

Tuberculosis

Associations, not evidence that every case has the same causal mechanism.

Slide 16 · Association: Chronic pelvic inflammatory disease

Chronic pelvic inflammatory disease is listed as an associated condition.

An ascending genital-tract process provides important clinical context.

Consider the cervix, uterus and fallopian tubes as connected sites.

Pelvic symptoms or infertility warrant clinical correlation.

Slide 17 · Association: Retained gestational tissue

Prior delivery / abortion

Gestational tissue persists

Persistent intrauterine inflammatory setting

Differentiate prolonged chronic inflammation from an acute postpartum infection.

Slide 18 · Association: Intrauterine contraceptive devices

Intrauterine contraceptive devices among associations.

Document device use in the pathology request and clinical history.

Presence of a device is not by itself a histologic diagnosis.

Do not infer a particular causative organism from device use alone.

Slide 19 · Tuberculous endometritis: Routes to the uterus

Miliary hematogenous spread

Drainage from tuberculous salpingitis

Endometrial involvement

The route from tuberculous salpingitis as more frequent.

Slide 20 · Tuberculosis: Interpret local epidemiology

An important specific infectious cause of chronic endometritis.

Endometrial tuberculosis is rare in high-resource countries.

Epidemiology and tubal disease affect the differential diagnosis.

Specific microbiologic evaluation belongs to the clinical workup.

Slide 21 · No cause apparent in some cases

No apparent cause in approximately 15% of cases.

The term “nonspecific” describes this clinical situation.

A negative etiologic assessment does not negate stromal plasma cells.

Separate diagnostic certainty from certainty about the cause.

Slide 22 · Chlamydia: A possible contributor

Chlamydia may be involved.

Acute neutrophilic inflammation may coexist with a chronic infiltrate.

The chronic component includes lymphocytes and plasma cells.

Histology alone does not speciate an organism.

Slide 23 · Inflammatory cell types carry different meanings

Cell type

Diagnostic interpretation

Neutrophil

Acute inflammatory component; Context matters

Lymphocyte

May be present in chronic or physiologic settings

Plasma cell

Key diagnostic finding in endometrial stroma

Mixed population

May occur with Chlamydia-associated inflammation

Slide 24 · Why negative cultures cannot settle the diagnosis

Responsible organisms may not be cultured.

Culture negativity does not exclude clinically suspected infection.

Distinguish pathogen detection from diagnosis of tissue inflammation.

Therapeutic decisions require clinical rather than histologic context alone.

Slide 25 · Clinical spectrum of chronic endometritis

Abnormal uterine bleeding

Pelvic or uterine pain

Genital-tract discharge

Infertility

Slide 26 · Abnormal uterine bleeding: A structural differential

Chronic endometritis among causes of abnormal bleeding.

Polyps, submucosal leiomyomas and endometrial neoplasms are alternatives.

Hormonal/anovulatory bleeding may mimic the presentation.

Pathology and clinical features must be considered together.

Slide 27 · Abnormal bleeding: Competing mechanisms

Possible cause

Primary diagnostic clue

Chronic endometritis

Stromal plasma cells

Endometrial polyp

Localized endometrial lesion

Submucosal leiomyoma

Smooth muscle mass encroaching on cavity

Anovulatory bleeding

Proliferative pattern / stromal breakdown

Endometrial neoplasm

Atypical neoplastic glandular or stromal lesion

Slide 28 · Pain and discharge: Clinically relevant, not specific

Some patients with nonspecific chronic endometritis report pain.

Discharge is another possible presentation.

Neither symptom identifies plasma cells or determines an organism.

Evaluate the whole genital tract and appropriate clinical context.

Slide 29 · Infertility is an association, not a histologic marker

Infertility among possible clinical manifestations.

Other gynecologic factors may independently affect fertility.

Do not diagnose chronic endometritis from infertility alone.

Interpret any biopsy finding within the full fertility evaluation.

Slide 30 · Clinical question → tissue-based diagnosis

Clinical suspicion

Endometrial sampling

Histologic assessment

Stromal plasma-cell identification

The diagnosis rests on the stroma, not on the presenting symptom.

Slide 31 · Microscopic map: Locate the cells that count

Gland

Stroma

Illustrative plasma cells

Original schematic — cell distribution is illustrative, not diagnostic evidence.

Slide 32 · Plasma cell: Core recognition features

Eccentric nucleus

Basophilic cytoplasm

Perinuclear pale zone

Schematic plasma cell morphology; Confirm against authentic H&E in routine practice.

Slide 33 · Where should plasma cells be identified?

Within the endometrial stromal compartment.

Not merely as positive staining within glandular epithelium.

Recognize the gland–stroma boundary before interpreting cells.

Preserve the tissue architecture in the diagnostic assessment.

Slide 34 · Plasma cells compared with other inflammatory cells

Cell

Useful cytologic distinction

Plasma cell

Eccentric nucleus, basophilic cytoplasm, pale hof

Small lymphocyte

Scant cytoplasm, round dense nucleus

Neutrophil

Segmented nucleus; Acute inflammatory pattern

Stromal fibroblast

Elongated or spindle-shaped nucleus

Slide 35 · Why plasma cells may be overlooked on H&E

Scattered stromal plasma cells can be sparse and subtle.

They may resemble stromal fibroblasts or mononuclear leukocytes.

Secretory change increases background cellular complexity.

Review suspicious regions carefully before excluding disease.

Slide 36 · A structured biopsy review

Check tissue representation

Orient glands and stroma

Assess cycle-related changes

Search for stromal plasma cells

Report findings with limitations

Slide 37 · Focality: A negative fragment has limitations

Plasma-cell involvement may be patchy rather than diffuse.

A small sample can miss a focal stromal infiltrate.

An inadequate biopsy cannot confidently rule out disease.

Record sample adequacy and interpret clinical discordance cautiously.

Slide 38 · H&E: Establish morphology before ancillary testing

Locate endometrial epithelium, glands and stroma.

Search for eccentric nuclei and perinuclear clearing.

Review areas with disproportionate stromal cellularity.

Use ancillary staining to clarify equivocal findings when appropriate.

Slide 39 · CD138 immunohistochemistry: Useful adjunct

H&E raises suspicion

CD138 highlights plasma-cell phenotype

Confirm stromal localization

Integrate with morphology

CD138 is an aid to recognition; It does not independently identify etiology.

Slide 40 · CD138 is not confined to plasma cells

Endometrial glandular and surface epithelial cells can stain.

Epithelial CD138 positivity must not be counted as stromal plasma cells.

Evaluate cell position and cytomorphology on the stained section.

Misreading epithelial signal may produce overdiagnosis.

Slide 41 · CD138 interpretation: Two very different signals

Stromal signal

Cell located between endometrial glands

Plasmacytoid morphology supports interpretation

Potential evidence of chronic endometritis

Epithelial signal

Surface or glandular lining is immunoreactive

Expected expression in epithelial compartments

Not proof of stromal plasma-cell infiltration

Slide 42 · Thresholds: An important standardization gap

No universally accepted plasma-cell density threshold exists.

Studies use differing field counts and positivity rules.

Do not teach a single numerical cutoff as a universal requirement.

Specify the laboratory approach when interpreting reports.

Slide 43 · Sampling timing may affect detection

Endometrial cycle phase changes the stromal background.

Published studies report higher plasma-cell detection in proliferative biopsies.

Sampling site and tissue amount also influence sensitivity.

Interpret small discordant specimens without overconfidence.

Slide 44 · Inflammatory infiltrate ≠ organism identification

The stromal plasma-cell criterion defines the histologic lesion.

Chlamydia is a possibility, not a microscopic certainty.

Tuberculosis requires additional clinicomicrobiologic correlation.

Culture may fail to recover the responsible organism.

Slide 45 · Diagnostic cautions: Avoid both false positives and negatives

Pitfall

Safer interpretation

Lymphocytes mistaken for plasma cells

Evaluate cytology; Use stain when appropriate

Epithelial CD138 miscounted

Verify stromal location

Focal plasma cells missed

Consider representativeness

Single cutoff treated as universal

State local or study-specific criteria

Slide 46 · Histologic chronic endometritis versus endometriosis

Endometritis is inflammation of the uterine endometrial lining.

Endometriosis is endometrial-type tissue at ectopic sites.

Stromal plasma cells support endometritis—not endometriosis.

The names are similar but the defining pathology differs.

Slide 47 · Related disorders: Location and key finding

Entity

Anatomic setting

Core pathology

Chronic endometritis

Uterine endometrium

Stromal plasma cells

Acute endometritis

Uterine endometrium

Acute stromal inflammation

Endometriosis

Extrauterine sites

Ectopic endometrial-type tissue

Endometrial polyp

Focal uterine lining

Polypoid structural lesion

Slide 48 · Acute versus chronic endometritis: Integrated comparison

Feature

Acute

Chronic

Typical context

After delivery / miscarriage

PID, retained tissue, IUD, TB

Diagnostic inflammation

Acute, nonspecific

Stromal plasma cells

Clinical interpretation

Recent gestational event

Bleeding, discharge, pain, infertility

Etiologic uncertainty

Bacterial infection

May be nonspecific / culture-negative

Slide 49 · Clinicopathologic integration: Rational reporting

Relevant history

Biopsy findings

Interpretive limitations

Clinical correlation

If no organism is identified, avoid naming a pathogen from morphology alone.

Slide 50 · Antibiotic treatment: Robbins’ conditional principle

When infection is clinically suspected, antibiotic treatment is indicated.

A negative culture does not necessarily prevent treatment.

The rationale includes prevention of sequelae such as salpingitis.

Drug choice and regimen are not specified by this textbook passage.

Slide 51 · Avoid claiming certainty about fertility benefit

Infertility is a relevant clinical association.

Evidence on whether eliminating plasma cells improves live birth remains uncertain.

Published studies vary in diagnostic criteria and patient selection.

Do not infer a quantified therapeutic benefit from histology alone.

Slide 52 · Case 1: Inflammation after miscarriage

A patient develops fever and uterine symptoms after miscarriage. Ultrasound raises concern for retained gestational products.

Interpretation question

Which inflammatory pattern is most consistent with this clinical setting?

Slide 53 · Case 1: Acute endometritis is the primary concern

Acute postabortion endometritis

Retained gestational tissue is the classic predisposing factor.

The acute response predominates in the endometrial stroma.

Management with evacuation and antibiotics.

Slide 54 · Case 2: Infertility and a subtle infiltrate

An endometrial biopsy obtained during an infertility assessment contains scattered stromal mononuclear cells. Plasma-cell morphology is uncertain.

Interpretation question

What finding would establish the histologic diagnosis?

Slide 55 · Case 2: Prioritize stromal plasma cells

Demonstrate plasma cells in the endometrial stroma

CD138 may clarify equivocal cells but is not specific for their location.

Do not count positively stained endometrial epithelium.

Interpret the result with the laboratory’s diagnostic framework.

Slide 56 · Case 3: Bleeding with an intrauterine device

A patient using an intrauterine contraceptive device reports intermittent abnormal uterine bleeding. Biopsy shows a possible inflammatory infiltrate.

Interpretation question

Does device history alone establish chronic endometritis?

Slide 57 · Case 3: Association does not equal diagnosis

No—look for stromal plasma cells

Intrauterine devices are a recognized clinical association.

Stromal plasma cells determine the histologic diagnosis.

Consider other causes of abnormal bleeding concurrently.

Slide 58 · Case 4: Genital tuberculosis context

A patient undergoing investigation for possible tubal tuberculosis has an endometrial biopsy. The clinical team asks whether the uterine cavity may be involved.

Interpretation question

What route of spread does Robbins emphasize?

Slide 59 · Case 4: Anatomic route informs suspicion

Spread from tuberculous salpingitis

Endometrial tuberculosis may also occur after miliary spread.

The route from the tube is described as more frequent.

The tissue and clinical data must be linked before assigning etiology.

Slide 60 · Diagnostic decision: A compact conceptual algorithm

Endometrial indication / symptoms

Adequate endometrial biopsy

Are stromal plasma cells present?

Report and correlate etiology

Absence on limited sampling and absence of a proven pathogen are different questions.

Slide 61 · High-yield clinicopathologic synthesis

The chronic lesion is identified by stromal plasma cells.

Classic associations include PID, retained tissue, devices and tuberculosis.

Nonspecific cases and negative cultures are recognized.

Cycle-related cells and CD138 epithelial staining are important pitfalls.

Clinical decisions integrate histology, history and microbiology.

Slide 62 · Selected references

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th ed. 2026. Chapter 22, pp. 910–913.

The Role of Plasma Cells as a Marker of Chronic Endometritis. Systematic review and meta-analysis. 2023. PMC10296269.

Endometritis—Diagnosis, Treatment and Its Impact on Fertility. Scoping review. 2022. PMC9355436.

International Expert Consensus Statement on Chronic Endometritis. 2026. PMC13263251.