Invasive lobular carcinoma

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Invasive lobular carcinoma, abbreviated ILC, is the second most common form of Invasive breast cancer.

Invasive lobular carcinoma
Diagnosis in short

Lobular carcinoma. H&E stain.
LM DDx invasive ductal carcinoma of the breast with lobular features, poorly differentiated carcinoma, LCIS
IHC E-cadherin -ve, usu. ER and PR +ve, HER2 -ve, CK7 +ve
Site breast - see invasive breast cancer

Syndromes hereditary diffuse gastric cancer

Prevalence relatively common
Clin. DDx other breast tumours

It may be referred to as lobular carcinoma; however, this may lead to confusion with lobular carcinoma in situ.

General

  • May be associated with a CDH1 mutation - seen in diffuse type gastric cancer.[1][2]

Microscopic

Features:

  • "Single file" - cell line-up in a row.
    • Cell should not be cohesive -- lymphoma should briefly come to mind.
      • primary lymphoma of the breast exists... but it is extremely rare.
  • NO gland formation.
    • If it forms glands... it is more likely NST.
  • May have signet ring morphology.
  • NO desmoplastic reaction, i.e. the stroma surrounding the tumour cells should look benign and undisturbed.

Note:

  • Commonly have low grade nuclear features.

DDx:

Subclassification

  • Classic lobular carcinoma.
    • Low nuclear grade - NO significant variation of nucleus size.
  • Pleomorphic lobular carcinoma.
    • Significant nuclear atypia.

Note:

  • Some pathologist grade lobular carcinoma like other types and avoid the term "pleomorphic lobular carcinoma."[3]

Other variants:

  • Histiocytoid.[4]

Images

IHC

Features:

  • E-cadherin -ve.
  • ER and PR +ve.
  • HER2 -ve.
  • CK7 +ve.

Others:

  • CK20 -ve.

See also

References

  1. URL: http://www.asco.org/ascov2/Meetings/Abstracts?&vmview=abst_detail_view&confID=65&abstractID=33006. Accessed on: 19 April 2011.
  2. Online 'Mendelian Inheritance in Man' (OMIM) 192090
  3. MUA. Jan 22, 2009.
  4. Tan, PH.; Harada, O.; Thike, AA.; Tse, GM. (Aug 2011). "Histiocytoid breast carcinoma: an enigmatic lobular entity.". J Clin Pathol 64 (8): 654-9. doi:10.1136/jcp.2011.088930. PMID 21398688.