Invasive lobular carcinoma

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 syndrome
Prevalence	relatively common
Clin. DDx	other breast tumours

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

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.

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:

• Invasive ductal carcinoma of the breast with lobular features.
• Poorly differentiated carcinoma.
• LCIS.

Images

• 

  Lobular carcinoma - low mag. (WC/Nephron)

• 

  Lobular carcinoma - high mag. (WC/Nephron)

• 

  Lobular carcinoma - very high mag. (WC/Nephron)

More WC images:

• Lobular carcinoma - 1 (WC).
• Lobular carcinoma - 2 (WC).

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."

IHC

Features:

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

Others:

• CK20 -ve.

See also

• Invasive breast cancer.
• Signet ring cell carcinoma.