Invasive Lobular Carcinoma
Epidemiology:
Common sites:
Gross features:
- usually a palpable mass
- a quarter only produce a vaguely thickened area
Histologic features:
- single infiltrating tumour cells (hallmark)
- often in single file
- loose clusters or sheets
- concentric rings surrounding normal ducts
frequently
- not forming tubules or papillae
- individual cells look the same as LCIS
- lack cohesion
- intracellular lumens, signet ring cells
- often minimal or absent desmoplastic response
Immunophenotype:
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Marker:
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Sensitivity:
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Specificity:
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ER
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70-95%
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PR
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60-70%
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GCDFP-15
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CK7
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E-cadherin (neg)
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Molecular features:
- CDH1 mutation (truncating)
- CDH promoter methylation
- deletions:
- CDH1 (16q22.1)
- loss of e-cadherin and Beta-catenin
- 8p23-p21
- 11q14.1-q25
- 13q
- gains
- Amplifications
- 1q32
- 8p12-p11.2
- 11q13
- 8q24 (PLC)
- 17q12 (PLC)
- 20q13 (PLC)
- Luminal A mostly by expression profiling
Other features:
- metastasize more frequently to:
- peritoneum
- retroperitoneum
- leptomeninges (carcinomatous meningitis)
- GI tract
- Ovaries
- Uterus
- Metastasize less frequently to:
References:
- WHO Classification of Tumours
of the Breast (2012)