Definition/General
Introduction:
Vulvar tubular carcinoma is a rare well-differentiated variant of adenocarcinoma characterized by well-formed tubular structures
Comprises less than 0.5% of all vulvar malignancies
Shows excellent prognosis when pure
Similar to breast tubular carcinoma
Demonstrates low metastatic potential.
Origin:
Arises from Bartholin glands or minor vestibular glands
Can originate from surface epithelium with glandular differentiation
Shows terminal duct differentiation
Associated with tubular adenosis in some cases
Demonstrates low-grade features.
Classification:
Classified as adenocarcinoma, tubular type
WHO classification includes under glandular tumors
Grade I (well-differentiated) by definition
Similar morphology to breast tubular carcinoma
Requires >90% tubular pattern for diagnosis.
Epidemiology:
Peak incidence in 5th-6th decades
Extremely rare with few reported cases
No HPV association
Better prognosis than conventional adenocarcinomas
Low recurrence rate with adequate excision.
Clinical Features
Presentation:
Small, firm vulvar nodule
Usually asymptomatic
May present as incidental finding
Slow growth pattern
Well-circumscribed on imaging
Rarely causes symptoms.
Symptoms:
Usually asymptomatic (70-80%)
Mild vulvar discomfort (20-30%)
Incidental discovery common
Bleeding rare
No pruritus typically
Mass effect minimal.
Risk Factors:
Advanced age (>50 years)
History of breast tubular carcinoma
Previous vulvar adenosis
Family history of breast/ovarian cancer
No established environmental factors.
Screening:
Regular gynecological examination
Careful palpation of vulvar area
Biopsy of small nodules
Genetic counseling if family history positive.
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Gross Description
Appearance:
Small, well-circumscribed nodule
Tan to gray-white cut surface
Firm consistency
Smooth borders
Usually small size.
Characteristics:
Size typically 0.5-3 cm in diameter
Well-demarcated from surrounding tissue
Cut surface shows solid, homogeneous appearance
No necrosis typically
May have chalky consistency.
Size Location:
Small size (usually 1-2 cm)
Can arise from any vulvar glandular area
Bartholin gland region common
May involve vestibular glands
Usually unifocal.
Multifocality:
Usually unifocal
May be associated with adenosis
Well-circumscribed growth
No lymph node involvement typically
Metastases extremely rare.
Microscopic Description
Histological Features:
Characterized by well-formed tubules in single file arrangement
Minimal cytological atypia
Low mitotic activity
Desmoplastic stroma
Angular tubular configuration.
Cellular Characteristics:
Small cuboidal cells
Minimal nuclear pleomorphism
Round to oval nuclei
Scant cytoplasm
Low mitotic index (<2/10 HPF)
Uniform cell population.
Architectural Patterns:
Tubular architecture >90% of tumor
Single file arrangement
Angular configuration
Desmoplastic stroma
Minimal solid areas
Well-formed lumina.
Grading Criteria:
Considered Grade I (well-differentiated)
Minimal nuclear atypia (Grade 1)
Tubule formation >90% (Grade 1)
Low mitotic count (Grade 1)
Excellent differentiation.
Immunohistochemistry
Positive Markers:
CK7 (positive)
CK8/18 (positive)
EMA (positive)
E-cadherin (positive)
ER (often positive)
PR (variable)
CEA (focal positive).
Negative Markers:
CK20 (negative)
p63 (negative)
CK5/6 (negative)
TTF-1 (negative)
CDX2 (negative)
HER2 (negative)
S-100 (negative).
Diagnostic Utility:
CK7 positivity supports glandular differentiation
E-cadherin confirms epithelial nature
p63 negativity excludes myoepithelial differentiation
ER positivity common (like breast counterpart)
Pattern similar to breast tubular carcinoma.
Molecular Subtypes:
Well-differentiated adenocarcinoma
Hormone receptor positive type (often)
Low-grade molecular profile
Similar to breast tubular carcinoma.
Molecular/Genetic
Genetic Mutations:
PIK3CA mutations (common)
AKT1 mutations (some cases)
Low-grade mutation profile
BRCA pathway alterations rare
Similar profile to breast tubular carcinoma.
Molecular Markers:
Low Ki-67 proliferation index (<10%)
Wild-type p53 pattern
ER/PR expression common
HER2 negativity
Low mutational burden.
Prognostic Significance:
Excellent prognosis
Low recurrence rate
Minimal metastatic potential
Stage at presentation usually early
Long-term survival excellent.
Therapeutic Targets:
Complete surgical excision
Hormonal therapy (ER-positive cases)
Conservative approach possible
No adjuvant chemotherapy typically needed.
Differential Diagnosis
Similar Entities:
Adenosis (atypical)
Microglandular hyperplasia
Metastatic breast carcinoma
Well-differentiated adenocarcinoma
Bartholin gland adenocarcinoma.
Distinguishing Features:
Tubular carcinoma: Infiltrative pattern
Tubular carcinoma: Desmoplastic stroma
Adenosis: Lobular architecture
Adenosis: No infiltration
Breast metastasis: Clinical history
Breast metastasis: GCDFP-15 positive.
Diagnostic Challenges:
Differentiation from atypical adenosis
Recognition of infiltrative pattern
Assessment of tubular percentage
Distinction from metastatic breast carcinoma
Low-power examination crucial.
Rare Variants:
Mixed patterns with conventional adenocarcinoma
Focal cribriform areas
Micropapillary component (rare)
Mucinous features (focal).
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
Vulvar Tubular Carcinoma
Classification
Classification: Adenocarcinoma, tubular type, Grade I
Histological Features
Shows well-formed tubules ([X]% of tumor) with [minimal atypia] and [desmoplastic stroma]
Size and Extent
Size: [X] cm, extent: [well-circumscribed with minimal invasion]
Margins
Margins are [uninvolved] with closest margin [X] mm
Tubular Pattern
Tubular pattern comprises [>90]% of tumor (diagnostic requirement met)
Grade Assessment
Grade I: [minimal atypia], [>90% tubules], [low mitotic count <2/10 HPF]
Immunohistochemistry
CK7: [positive], EMA: [positive]
ER: [positive/negative], PR: [positive/negative]
p63: [negative], CK5/6: [negative]
Prognostic Factors
Tubular pattern (excellent prognosis), Grade I, hormone receptor status
Final Diagnosis
Vulvar Tubular Carcinoma (Grade I) - EXCELLENT PROGNOSIS