Definition/General
Introduction:
Ovarian adenoid cystic carcinoma is an extremely rare malignant tumor showing cribriform pattern similar to salivary gland tumors
Represents less than 0.1% of ovarian malignancies
Shows dual cell population (epithelial and myoepithelial)
Contains pseudocystic spaces filled with basement membrane material
Associated with MYB-NFIB fusion in some cases.
Origin:
Arises from surface epithelium with dual differentiation
May originate from inclusion cysts with metaplastic change
Shows myoepithelial differentiation similar to salivary gland
Results from MYB gene rearrangements (when present)
Represents unique histogenetic pathway.
Classification:
Classified under WHO 2020 as rare variant of surface epithelial tumor
Low to intermediate grade typically
Three histological patterns: cribriform, tubular, solid
MYB-NFIB fusion characteristic (when present)
FIGO staging follows standard protocols.
Epidemiology:
Peak incidence in 5th-7th decades (40-70 years)
Postmenopausal women predominantly
Unilateral disease typical (>90%)
Indolent behavior compared to other ovarian carcinomas
Indian population shows similar age distribution
Excellent prognosis when localized.
Clinical Features
Presentation:
Slow-growing pelvic mass (most common)
Incidental finding during routine examination
Long symptom duration before diagnosis
Early stage presentation typical
Unilateral disease in >90%
Minimal constitutional symptoms.
Symptoms:
Mild pelvic discomfort (chronic)
Abdominal bloating (gradual onset)
Urinary frequency due to mass effect
Minimal pain typically
Normal menstrual cycles
Slow progression of symptoms.
Risk Factors:
Age >40 years
No specific genetic predisposition
Postmenopausal status
No hormonal associations identified
Environmental factors unclear
Sporadic occurrence typical.
Screening:
Transvaginal ultrasound shows solid mass
CA-125 typically normal
CT/MRI demonstrates solid tumor
Tissue biopsy required for diagnosis
Molecular testing for MYB rearrangement
No specific serum markers.
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Gross Description
Appearance:
Solid, well-circumscribed tumor
Gray-white cut surface with firm consistency
Smooth external surface
Minimal necrosis or hemorrhage
Homogeneous appearance on cut section.
Characteristics:
Firm, rubbery consistency
Gray-white to tan coloration
Well-defined margins
Solid architecture predominantly
No cystic components typically
Surface involvement rare.
Size Location:
Size ranges from 3-12 cm (median 6 cm)
Unilateral involvement >90%
Can arise anywhere in ovary
Well-localized tumor
Bilateral disease extremely rare
Confined to ovary typically.
Multifocality:
Unifocal presentation >95%
Bilateral involvement extremely rare (<5%)
Extraovarian spread uncommon
Lymph node involvement rare
Peritoneal implants uncommon
Indolent behavior.
Microscopic Description
Histological Features:
Dual cell population: epithelial and myoepithelial cells
Cribriform pattern with pseudocystic spaces
Basaloid appearance
Basement membrane material in spaces
Perineural invasion may be present
Minimal mitotic activity.
Cellular Characteristics:
Small, uniform cells with minimal pleomorphism
Basaloid morphology
Dark, hyperchromatic nuclei
Scant cytoplasm
Dual cell types: luminal and abluminal
Myoepithelial cells at periphery.
Architectural Patterns:
Cribriform pattern (most common)
Tubular pattern
Solid pattern (high-grade areas)
Pseudocystic spaces contain PAS-positive material
Infiltrative growth at periphery
Perineural invasion characteristic.
Grading Criteria:
Low-grade (cribriform/tubular patterns)
Intermediate-grade (mixed patterns)
High-grade (solid pattern >30%)
Mitotic activity low in most cases
Nuclear pleomorphism minimal
Solid component percentage determines grade.
Immunohistochemistry
Positive Markers:
CK7 (luminal cells, 90-95%)
PAX8 (85-90% cases)
p63 (myoepithelial cells, 80-85%)
Calponin (myoepithelial cells, 70-75%)
SMA (myoepithelial cells, 60-70%)
c-kit/CD117 (70-80%)
SOX10 (myoepithelial cells, 50-60%).
Negative Markers:
CK20 (negative)
CDX2 (negative)
TTF1 (negative)
WT1 (typically negative)
Calretinin (negative)
Inhibin (negative)
Chromogranin (negative).
Diagnostic Utility:
Dual cell population IHC pattern diagnostic
p63/calponin positivity in myoepithelial cells
PAX8 positivity confirms ovarian origin
c-kit positivity supportive
CK7+/CK20- pattern typical
SOX10 highlights myoepithelial component.
Molecular Subtypes:
MYB-NFIB fusion positive subtype (when present)
Low-grade molecular profile
MYB overexpression
Low Ki-67 proliferation (<10%)
p53 wild-type pattern
Unique transcriptional profile.
Molecular/Genetic
Genetic Mutations:
MYB-NFIB translocation (when present)
MYB gene rearrangements
NOTCH pathway alterations
TP53 mutations uncommon (<5%)
PIK3CA mutations rare
Low mutational burden overall.
Molecular Markers:
MYB overexpression (majority of cases)
MYB-NFIB fusion (subset)
Low Ki-67 proliferation (<10%)
p53 wild-type pattern
SOX10 expression (myoepithelial cells)
c-kit expression.
Prognostic Significance:
Indolent behavior with slow growth
Excellent prognosis when localized
Stage at presentation most important factor
Solid pattern associated with worse prognosis
Perineural invasion may indicate aggressive behavior
Local recurrence possible if incompletely excised.
Therapeutic Targets:
c-kit inhibitors (imatinib) investigational
NOTCH inhibitors experimental
Standard chemotherapy limited efficacy
Complete surgical resection curative
Targeted therapy based on molecular profile
Radiation therapy for local control.
Differential Diagnosis
Similar Entities:
Primary ovarian carcinoid tumor
Sex cord stromal tumor with cribriform pattern
Metastatic adenoid cystic carcinoma (salivary gland)
Sertoli cell tumor
Granulosa cell tumor
Small cell carcinoma.
Distinguishing Features:
vs Carcinoid: Chromogranin negative
Different architecture
vs Sex cord: Inhibin/calretinin negative
PAX8 positive
vs Salivary metastasis: Clinical correlation
PAX8 positive in ovarian
vs Sertoli cell: Different IHC profile
Lacks Call-Exner bodies.
Diagnostic Challenges:
Extremely rare entity
Morphological overlap with other small cell tumors
Dual cell population may be subtle
IHC panel essential
Molecular confirmation helpful
Clinical correlation required.
Rare Variants:
Solid adenoid cystic carcinoma
Adenoid cystic with clear cells
Mixed adenoid cystic-serous pattern
Cystic adenoid cystic carcinoma
Each requires comprehensive workup.
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
Right/Left ovary and fallopian tube, measuring [X x Y x Z] cm
Gross Description
Solid, well-circumscribed [X] cm tumor with gray-white cut surface
Microscopic Description
Tumor with dual cell population showing [cribriform/tubular/solid] pattern with [grade] features
Immunohistochemistry
CK7: Positive (luminal), PAX8: Positive, p63: Positive (myoepithelial), c-kit: Positive
Diagnosis
Ovarian Adenoid Cystic Carcinoma, [Low/Intermediate/High] Grade, Stage [stage]
Final Diagnosis
Right/Left Ovarian Adenoid Cystic Carcinoma, Grade [X], FIGO Stage [X]