Differential Diagnosis
Tubular Carcinoma Sclerosing Adenosis
Stellate, infiltrating
Circumscribed, nodular
Patent ducts, gaping lumens
Many ducts have obliterated lumens
Minimal branching
Frequent branching
Single layer of cells
Sometimes more than one layer of cells
Cells polarized to lumen
Cells smaller, streaming
Myoepithelial cell absent
Myoepithelial cells present
Tubular Carcinoma Microglandular Adenosis
Stellate, infiltrating
Nodular or diffuse
Round to oval ducts with pointed ends and gaping lumens
Uniform small round ducts with small lumens
Frequent apical snouts
No apical snouts
Empty lumens
Eosinophilic secretion present in at least some lumens
Larger cells, polarized to lumen
Cells smaller, flatter
Round nuclei
Nuclei may be flat, parallel to base
EMA positive
EMA negative
Basement membrane absent
Basement membrane variable
Both have rounded non-branching ducts with a single layer of cells, lacking myoepithelial cells
Tubular Carcinoma Tubular Adenosis
Stellate, infiltrating
Diffuse
Frequent apical snouts
No apical snouts
Ducts with frequent pointed ends
Infrequent pointed ends
Empty lumens
Eosinophilic secretion present in at least some lumens
Stroma desmoplastic
Stroma usually hypocellular or fat
No myoepithelial cells
Myoepithelial cells
Tubular Carcinoma Radial Scar
Single layer of cells
Often multiple cell layers
No myoepithelial cells
Myoepithelial cells present
Frequent infiltration of fat by naked tubules
No bare infiltration of fat
No epithelial hyperplasia
May show epithelial hyperplasia
Both have a stellate configuration with radiating fibrous arms and fibroelastotic stroma
Tubular Carcinoma Grade I Infiltrating Ductal Carcinoma, NOS
Stellate infiltration
Irregular infiltration
90% tubules
May have >10% ribbons or cords
Infrequent branching
Frequent budding and branching
Single layer of cells
May show stratification
Uniform chromatin
Slightly irregular chromatin
Nucleoli inconspicuous
Nucleoli may be prominent
A continuum exists between tubular carcinoma and well differentiated (Grade I) infiltrating ductal carcinoma
It is probable that a small (under 2.0 cm) well differentiated infiltrating ductal carcinoma will have a prognosis similar to that of tubular carcinoma so the distinction may not be critical
Grade II and III carcinomas are excluded by definition from tubular carcinoma.
Both are typically E-cadherin positive
Tubular Carcinoma vs Cribriform Carcinoma
Low grade cribriform carcinoma and tubular carcinoma both have nearly 100% survival
We report mixtures of these two types simply as the predominant type
90% pure architectural pattern rule does not apply
Tubular Carcinoma Low Grade Adenosquamous Carcinoma
Uniform, gaping tubules
Irregular, frequently compressed lumens
Tubules frequently have pointed ends
Tubules frequently have long comma-shaped tails
No squamous differentiation
At least focal squamous differentiation
No myoepithelial component
Myoepithelial cells prominently present around tubules
Both are low grade cytologically and clinically
