Tubular Carcinoma of the Breast
Definition
- A low grade breast carcinoma at least 90% of appears to be composed of well differentiated tubules
Diagnostic Criteria
- Stellate infiltrating configuration
- Fibrous arms radiate out
- Frequently infiltrates fat without a fibrous reaction
- 90% composed of small, minimally branched, oval to round duct-like structures with gaping lumens
- Ducts frequently have pointed ends ("prows")
- Ducts lined by a single row of cells and are widely patent
- Apical snouts common
- Bridging by small columns of cells is OK
- Sheet-like stratification not seen
- Low grade cribriform carcinoma has same behavior so may constitute more than 10%
- Report mixtures of these two simply as the predominant type
- Nuclear grade I in at least 90% of cells
- Slightly enlarged cells
- Uniform nuclei, inconspicuous nucleoli, uniform chromatin
- Pleomorphism minimal or absent
- Mitotic figures unusual
- Remaining 10% must not show nuclear grade III
- Behavior may be that of the high grade component
- Report such tumors as mixtures of two types
- 95% are less than 2.0 cm diameter, most are less than 1 cm
- Basement membrane absent by PAS and laminin stains and by EM
- Myoepithelial cells absent on immunohistochemical stains
- (Tubular carcinoma is not really tubular)
Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting: May 1, 2006
Updates: February 13, 2009