Definition/General
Introduction:
Cervical adenoid cystic carcinoma is a rare malignant epithelial tumor characterized by a dual cell population forming cribriform, tubular, and solid patterns
It shows morphological similarity to adenoid cystic carcinoma of salivary glands.
Origin:
Arises from cervical glandular epithelium, possibly from minor salivary gland rests or transformation of endocervical glands
Maintains characteristic dual cell population throughout.
Classification:
WHO Classification recognizes this as a rare variant of cervical adenocarcinoma
Classified into cribriform, tubular, and solid subtypes based on predominant pattern.
Epidemiology:
Extremely rare with fewer than 100 cases reported worldwide
Peak incidence 40-60 years
No clear association with HPV infection
Generally slow-growing but locally aggressive.
Clinical Features
Presentation:
Abnormal vaginal bleeding
Cervical mass or induration
May present with advanced local disease
Symptoms of mass effect in pelvis.
Symptoms:
Vaginal bleeding (irregular or postmenopausal)
Pelvic pain
Urinary frequency or retention
Rectal pressure
Leg pain (nerve involvement).
Risk Factors:
No specific risk factors identified
Not associated with HPV infection
No hormonal associations
Family history not contributory.
Screening:
May be detected on Pap smear but often normal
Colposcopy may show submucosal lesion
Imaging shows characteristic patterns
Biopsy diagnostic.
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Gross Description
Appearance:
Firm, indurated cervical mass
May be endophytic or exophytic
Cut surface shows gray-white appearance with possible cystic areas.
Characteristics:
Size variable (1-8 cm)
Hard consistency
Gray-white to tan coloration
May show honey-comb appearance on cut surface
Infiltrative borders.
Size Location:
Usually involves entire cervix
Extends deeply into cervical stroma
Parametrial involvement common
May involve corpus uteri.
Multifocality:
Usually unifocal but infiltrative
Perineural spread characteristic
Distant metastases may occur but usually late in course.
Microscopic Description
Histological Features:
Dual cell population with ductal and myoepithelial cells
Cribriform pattern with pseudocysts containing basophilic material
Perineural invasion characteristic.
Cellular Characteristics:
Ductal cells: cuboidal with moderate cytoplasm
Myoepithelial cells: smaller, darker, angular nuclei
Overall bland cytologic features
Low mitotic activity.
Architectural Patterns:
Cribriform pattern (most common)
Tubular pattern with true lumina
Solid pattern (worst prognosis)
Perineural and intraneural invasion frequent.
Grading Criteria:
Grade I: pure cribriform/tubular
Grade II: <30% solid
Grade III: ≥30% solid pattern
Higher grade associated with worse prognosis.
Immunohistochemistry
Positive Markers:
Ductal cells: CK7+, EMA+, CEA+
Myoepithelial cells: p63+, SMA+, calponin+
c-kit (CD117) positive
CK5/6 in myoepithelial cells.
Negative Markers:
CK20 negative
TTF-1 negative
CDX2 negative
ER/PR usually negative
Neuroendocrine markers negative.
Diagnostic Utility:
Dual population confirmed by different staining patterns
p63 highlights myoepithelial cells
c-kit positivity supportive but not specific.
Molecular Subtypes:
MYB-NFIB fusion in some cases
MYBL1 rearrangements also described
Molecular testing may aid in diagnosis and prognosis.
Molecular/Genetic
Genetic Mutations:
MYB-NFIB gene fusion (t(6;9)(q22-23;p23-24)) in subset of cases
MYBL1 rearrangements
Low overall mutational burden.
Molecular Markers:
MYB protein overexpression in fusion-positive cases
FISH can detect characteristic translocations
Low Ki-67 proliferation index typically.
Prognostic Significance:
Solid pattern predicts worse outcome
Perineural invasion important prognostic factor
Size and stage also significant
Long-term follow-up essential.
Therapeutic Targets:
Limited targeted therapy options currently
MYB pathway potential target
Surgery remains primary treatment
Radiation for positive margins.
Differential Diagnosis
Similar Entities:
Conventional cervical adenocarcinoma
Basaloid squamous carcinoma
Adenoid basal carcinoma
Metastatic adenoid cystic carcinoma
Small cell carcinoma.
Distinguishing Features:
Adenoid cystic: Dual population, p63+ cells
Basaloid SCC: p63+ throughout, no true glands
Adenocarcinoma: Single cell type, CEA+.
Diagnostic Challenges:
Small biopsy may not show characteristic features
Requires recognition of dual cell population
Distinction from metastatic disease.
Rare Variants:
High-grade transformation
Dedifferentiated areas
Mixed with conventional adenocarcinoma
Oncocytic features described.
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.
Specimen Information
[specimen type], measuring [size] cm in greatest dimension
Diagnosis
Cervical adenoid cystic carcinoma
Classification
Classification: Adenoid cystic carcinoma, grade [I-III], [pattern] predominant
Histological Features
Shows dual cell population with [predominant pattern] architecture
Size and Extent
Size: [X] cm, extent: [local invasion pattern]
Margins
Margins are [involved/uninvolved] with closest margin [X] mm
Perineural Invasion
Perineural invasion: [present/absent - characteristic when present]
Lymph Node Status
Lymph nodes: [X] positive out of [X] examined
Special Studies
IHC: p63 highlights myoepithelial cells, c-kit positive
Molecular: [MYB-NFIB fusion status if tested]
[other study]: [result]
Prognostic Factors
Prognostic factors: [grade, size, perineural invasion]
Final Diagnosis
Final diagnosis: Cervical adenoid cystic carcinoma, grade [X]