Table of Contents
Definition / general | Clinical features | Prognostic factors | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Virtual slides | Cytology description | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosisCite this page: Tubular carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/breastmalignanttubular.html. Accessed July 14th, 2017.
Definition / general
- Special type of breast carcinoma with favorable prognosis, composed of distinct, well differentiated angular tubular structures (90%+ according to WHO) with open lumina, lined by a single layer of epithelial cells
- Not actually tubular - pattern is better described as a necklace formed by a string of beads (Stanford University - Tubular Carcinoma of the Breast)
Clinical features
- 2 - 6% of all malignant breast tumors
- Often multifocal / multicentric (20 - 55%, Am J Surg Pathol 1997;21:653), family history of breast carcinoma (40%)
- Usually presents with pT1 and pN0 disease (Int J Radiat Oncol Biol Phys 2009;75:1304)
Prognostic factors
- A well differentiated variant with very favorable prognosis (low rate of recurrence or metastasis) and only rare deaths (Am J Surg 2009;197:674)
- Excellent prognosis is restricted to tumors with 70%+ tubules, pure grade 1 nuclei and no / rare mitoses (Am J Clin Pathol 2004;122:728)
- Mixture with ordinary ductal carcinoma has worse prognosis (Hum Pathol 1983;14:694)
- Cause specific survival is 97% at 10 years (Eur J Surg Oncol 2005;31:9)
- 10 - 27% have axillary metastases, often micrometastases (Eur J Surg Oncol 2006;32:488), but still have excellent prognosis (Breast J 2003;9:298)
Treatment
- Surgery, long term followup for local recurrence and possibly radiation therapy (Breast Cancer Res Treat 2005;93:199, Breast J 2005;11:129)
Gross description
- Poorly circumscribed margins, hard consistency, mean size 1 cm
Microscopic (histologic) description
- 90%+ tubules with low grade features, irregular angulated contours of glands ("teardrop-like"), open lumina with apocrine-like snouts and basophilic secretions / columnar cell lesions in almost all cases (Adv Anat Pathol 2008;15:140), usually with flat epithelial atypia (Am J Surg Pathol 2007;31:417, Pathol Int 2008;58:620)
- Also desmoplastic stroma
- May form trabecular bars
- Frequently invades fat at periphery
- Fibrous, cellular and elastotic stroma
- Associated with low grade DCIS in 40 - 65% (micropapillary or cribriform), less often LCIS
- Minimal pleomorphism
- No myoepithelial layer, no mitotic figures, no necrosis, no angiolymphatic or perineural invasion and no basement membrane after PAS or type IV collagen staining
Microscopic (histologic) images
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Cytology description
- Increased cellularity, somewhat angular epithelial clusters and single epithelial cells
- Cells are bland and orderly with variable atypia and variable number of prominent myoepithelial cells (Acta Cytol 1997;41:1139, Am J Clin Pathol 1994;101:488)
Positive stains
- ER, PR and E-cadherin (but reduced)
Negative stains
- HER2 (Am J Clin Pathol 2006;126:55), p53 and EGFR
- Myoepithelial markers (p63, CD10, smooth muscle actin, CK5 / 6)
Electron microscopy description
- Ductal differentiation, no myoepithelial cells and no basement membrane
Molecular / cytogenetics description
- Usually diploid
- 16q- (78% of tumors), 1q+ (50%), but fewer overall chromosomal changes than ductal NOS (Hum Pathol 2001;32:222)
- Clonally related to flat epithelial atypia and low grade DCIS (Am J Surg Pathol 2009;33:1646)
Differential diagnosis
- Benign sclerosing lesion: overall lobular architecture, compression of glandular structures, positive for myoepithelial markers p63 and CD10 or smooth muscle actin (Appl Immunohistochem Mol Morphol 2006;14:71)
- Fibroadenoma: biphasic tumor with overgrowth of epithelial and stromal tissue; no true angulated contours of cells (may be compressed by stroma), no desmoplastic stroma
- Microglandular adenosis: more rounded tubules, often with colloid-like secretory material (Am J Surg Pathol 1982;6:401)
- Ductal carcinoma, low grade: actual tubules, not angular; usually no apocrine-like snouts with basophilic secretions / columnar cell lesions


























