Definition/General

Introduction:
-Endometrial Endometritis is inflammation of the endometrium characterized by inflammatory cell infiltration
-It can be acute or chronic
-Chronic endometritis is defined by presence of plasma cells
-It may be associated with infectious or non-infectious causes.
Origin:
-Results from ascending infection from lower genital tract
-Can be caused by bacterial, viral, or fungal pathogens
-May follow instrumentation or delivery
-Retained products of conception can cause inflammation
-IUD may predispose to chronic endometritis.
Classification:
-Acute endometritis: Neutrophilic infiltrate
-Chronic endometritis: Plasma cell infiltrate
-Granulomatous endometritis: Tuberculosis, sarcoidosis
-Lymphocytic endometritis: Viral infections
-Necrotizing endometritis: Severe infections
-Xanthogranulomatous endometritis: Rare form.
Epidemiology:
-Common in reproductive age women
-Higher incidence after delivery or abortion
-Associated with IUD use
-Chronic endometritis in 10-15% of infertile women
-Higher prevalence in developing countries
-Associated with sexually transmitted infections.

Clinical Features

Presentation:
-Abnormal uterine bleeding (most common)
-Pelvic pain
-Fever (acute cases)
-Purulent discharge
-Infertility
-Recurrent pregnancy loss
-Postmenopausal bleeding (elderly)
-Asymptomatic (chronic cases).
Symptoms:
-Menstrual irregularities
-Intermenstrual bleeding
-Heavy menstrual bleeding
-Pelvic pain and tenderness
-Fever and chills (acute)
-Malodorous discharge
-Dyspareunia
-Lower abdominal pain.
Risk Factors:
-Recent delivery or abortion
-IUD insertion
-Endometrial biopsy
-Sexually transmitted infections
-Immunocompromised state
-Diabetes mellitus
-Retained products of conception
-Cervical stenosis.
Screening:
-Endometrial biopsy for tissue diagnosis
-Microbiological culture
-PCR for specific pathogens
-Complete blood count
-ESR and CRP
-Transvaginal ultrasound
-Hysteroscopy with biopsy.

Master Endometritis Pathology with RxDx

Access 100+ pathology videos and expert guidance with the RxDx app

Get it on Google Play Download on the App Store

Gross Description

Appearance:
-Thickened and hyperemic endometrium
-Purulent exudate may be present
-Hemorrhagic areas
-May show necrotic tissue
-Friable consistency
-Associated debris or foreign material
-Enlarged uterus possible.
Characteristics:
-Red, swollen endometrial surface
-Purulent discharge
-Irregular surface
-May show ulceration
-Hemorrhage and necrosis
-Foul odor possible
-Associated pyometra in severe cases.
Size Location:
-Usually diffuse involvement
-May be focal around foreign body
-Fundal predominance sometimes
-Can involve entire endometrial cavity
-Associated myometrial involvement possible
-Extension to fallopian tubes.
Multifocality:
-Diffuse pattern most common
-Patchy involvement possible
-May be more severe in certain areas
-Associated with retained products
-Can extend to myometrium
-Ascending infection pattern.

Microscopic Description

Histological Features:
-Inflammatory cell infiltrate in endometrial stroma
-Acute: Neutrophils predominant
-Chronic: Plasma cells characteristic
-Lymphocytes and macrophages
-Surface epithelial damage
-Glandular changes
-Vascular congestion.
Cellular Characteristics:
-Plasma cells (diagnostic of chronic endometritis)
-Neutrophils (acute inflammation)
-Lymphocytes and histiocytes
-Eosinophils (allergic/parasitic)
-Epithelial reactive changes
-Stromal cell proliferation
-Endothelial swelling.
Architectural Patterns:
-Preserved glandular architecture usually
-Surface epithelial loss
-Stromal edema and hemorrhage
-Microabscesses in severe cases
-Granulation tissue formation
-Fibrosis in chronic cases
-Metaplastic changes.
Grading Criteria:
-Mild: Minimal inflammation, preserved architecture
-Moderate: Moderate inflammation, some architectural distortion
-Severe: Extensive inflammation, significant tissue damage
-Chronic activity: Plasma cells present
-Acute activity: Neutrophils predominant.

Immunohistochemistry

Positive Markers:
-CD138 (plasma cells)
-CD20 (B-lymphocytes)
-CD3 (T-lymphocytes)
-CD68 (macrophages)
-Myeloperoxidase (neutrophils)
-CD31 (endothelial cells)
-Smooth muscle actin (myofibroblasts).
Negative Markers:
-Cytokeratin in inflammatory cells
-Vimentin positive in stromal cells
-ER/PR may be decreased in inflamed areas
-CD10 in endometrial stroma
-Calretinin negative.
Diagnostic Utility:
-CD138 highlights plasma cells (diagnostic of chronic endometritis)
-CD68 identifies macrophages
-CD3/CD20 characterize lymphoid infiltrate
-Myeloperoxidase confirms neutrophils
-Special stains for microorganisms
-PAS for fungi.
Molecular Subtypes:
-Bacterial endometritis (most common)
-Viral endometritis (CMV, HSV)
-Fungal endometritis (Candida)
-Tuberculous endometritis
-Non-infectious endometritis
-Foreign body endometritis.

Molecular/Genetic

Genetic Mutations:
-No specific mutations in endometritis
-Inflammatory gene upregulation
-Cytokine pathway activation
-Toll-like receptor signaling
-NF-kB pathway activation
-Complement cascade activation.
Molecular Markers:
-Inflammatory cytokines (IL-1, TNF-α)
-Chemokines (IL-8, MCP-1)
-Acute phase proteins
-Matrix metalloproteinases
-Prostaglandins
-Nitric oxide production
-Complement proteins.
Prognostic Significance:
-Good prognosis with appropriate treatment
-Chronic endometritis associated with infertility
-Risk of ascending infection
-Recurrence possible if underlying cause persists
-Complications: PID, infertility, ectopic pregnancy
-Complete resolution possible.
Therapeutic Targets:
-Antibiotic therapy (broad-spectrum initially)
-Specific antimicrobials based on culture
-Anti-inflammatory agents
-Remove foreign body (IUD)
-Surgical drainage (pyometra)
-Hormonal therapy (restoration of cycle).

Differential Diagnosis

Similar Entities:
-Endometrial hyperplasia
-Endometrial carcinoma
-Retained products of conception
-Endometrial polyp with inflammation
-Adenomyosis
-Pyometra
-Gestational trophoblastic disease.
Distinguishing Features:
-Endometritis: Plasma cells present
-Endometritis: Inflammatory infiltrate
-Hyperplasia: Glandular crowding
-Carcinoma: Nuclear atypia and invasion
-RPOC: Chorionic villi
-Adenomyosis: Endometrial glands in myometrium.
Diagnostic Challenges:
-Mild chronic endometritis versus normal variation
-Reactive epithelial changes versus dysplasia
-Associated hyperplasia or atypia
-Sampling adequacy
-Crush artifact
-Concurrent pathology.
Rare Variants:
-Granulomatous endometritis (TB, sarcoidosis)
-Eosinophilic endometritis
-Necrotizing endometritis
-Xanthogranulomatous endometritis
-Viral endometritis (CMV, HSV)
-Fungal endometritis.

Sample Pathology Report

Template Format

Sample Pathology Report

Complete Report: This is an example of how the final pathology report should be structured for this condition.

Patient Information

Name: [Patient Name]\nAge: [X] years\nMRN: [Medical Record Number]\nDate of Procedure: [Date]

Clinical History

Clinical indication: [Abnormal uterine bleeding/Pelvic pain/Fever/Purulent discharge/Infertility workup]\nRelevant history: [Recent delivery/abortion/IUD insertion/Instrumentation/Other risk factors]\nClinical findings: [Fever/Pelvic tenderness/Purulent discharge]

Specimen Received

Specimen type: Endometrial [biopsy/curettage]\nSpecimen volume: [X] cc of tissue fragments\nFixative: 10% neutral buffered formalin\nMicrobiological culture: [Sent/Not sent]

Gross Examination

The specimen consists of [X] cc of [tan-pink/hemorrhagic/purulent] tissue fragments measuring up to [X] cm in aggregate. [Purulent material/debris] is [present/absent]. The tissue is entirely submitted for histological examination in [X] cassettes.

Microscopic Examination

Sections show endometrium with [acute/chronic/mixed] inflammatory infiltrate. [Acute inflammation: Prominent neutrophilic infiltrate with surface epithelial damage and stromal edema.] [Chronic inflammation: Plasma cells are readily identified within the endometrial stroma, diagnostic of chronic endometritis. Lymphocytes and histiocytes are also present.] The inflammation is [mild/moderate/severe] in degree and [focal/diffuse] in distribution. [Surface epithelial ulceration/reactive atypia] is [present/absent]. [Microorganisms/foreign material] are [identified/not identified]. Background endometrium shows [proliferative/secretory/atrophic/irregular] pattern.

Special Stains (if performed)

CD138 (plasma cell marker): [Highlights numerous plasma cells in stroma/Negative]\nGram stain: [Positive for gram-positive/gram-negative bacteria/Negative]\nPAS stain: [Positive for fungal elements/Negative]\nOther: [Specify stain and result]

Final Diagnosis

[ACUTE/CHRONIC/MIXED] ENDOMETRITIS\n\nSeverity: [Mild/Moderate/Severe]\nDistribution: [Focal/Diffuse]\nPlasma cells: [Present/Absent] (required for chronic endometritis diagnosis)

Comments

• [Chronic endometritis diagnosed by presence of plasma cells in endometrial stroma.]\n• Clinical correlation recommended for identification of underlying cause.\n• Consider microbiological culture and sensitivity testing.\n• Broad-spectrum antibiotic therapy recommended pending culture results.\n• Remove any foreign body (IUD) if present and contributing to infection.\n• Follow-up biopsy may be considered after treatment to document resolution.\n• [Associated with infertility - treatment may improve fertility outcomes.]

Reported By

Dr. [Pathologist Name], MD\nConsultant Pathologist\nDate: [Report Date]