Tubular Carcinoma
Epidemiology:
Common sites:
Gross features:
- multifocal in 10 to 56%
- bilateral in 9 to 38%
Histologic features:
- lobulocentricity
not maintained (in contrast to sclerosing adenosis)
- well-formed, open tubules with a single layer of
epithelial cells enclosing a clear lumen (>90% of the tumour required)
- may be mistaken for benign sclerosing
lesions
- open, angulated tubules
- contrast to more rounded and regular tubules
of microglandular adenosis
- absent myoepithelial
layer
- some may have an incomplete surrounding layer
of basement membrane
- cribriform spaces may be present
- well-differentiated by definition (low-grade by
definition)
- tumours
comprised of 50-90% of tubules, admixed with another morphology, should
be regarded as mixed type
- composite cells small to moderate size
- regular with little nuclear pleomorphism
(absence of marked pleomorphism is a
requirement)
- inconspicuous nucleoli
- scanty mitotic figures
- low mitotic activity (lack of marked mitotic
activity is required)
- apocrine snouts often (up to 1/3 of cases)
- desmoplastic stroma commonly accompanying
tubular structures
- association with radial scar maybe
- calcifications within lumens may be present
- FEA associated frequently
- DCIS, low-grade frequently
- LCIS less commonly present
Immunophenotype:
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Marker:
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Sensitivity:
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Specificity:
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ER, PR
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>95%
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HER2 (neg)
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Typically
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EGFR (neg)
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Typically
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P-cadherin (neg)
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Typically
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P53 (neg/normal)
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Typically
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HMWK (neg)
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Typically
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Collagen IV (neg)
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Laminin (neg)
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Molecular features:
- Diploid
- Low frequency of genetic alterations
- “luminal A” molecular class
- Losses:
- 16q (78-86%) (concomitant with 1q gain usually)
- 8p
- 3p (FHIT)
- 11q (ATM)
- Gains:
- 1q (50-62%) (concomitant with 16q loss usually)
- 16p
- Infrequently:
Other features:
- excellent prognosis
- lymph node mets in
<10%
- usually only one axillary lymph node
- prognosis is still very good
- typically detected on mammography
References:
- WHO Classification of Tumours
of the Breast (2012)