Medullary carcinoma

Medullary carcinoma represents 5 to 7% of invasive breast carcinomas
It is considered as variant of ductal carcinoma
Mean age of presentation is 45 -54 years. Patients are relatively younger than ductal carcinoma NOS
Mammographically – well circumscribed nodule
Gross features
- Tumor is soft and fleshy like marrow, hence the term medullary (Medulla is Latin word for marrow)
- Smaller size of 2 to 3 cms
- Well circumscribed with distinct margins often resembling benign lesion clinically and mammographically
- Haemorrhage and necrosis are rarely present

Microscopic features
- Five classical diagnostic features of Medullary carcinoma are
  - Syncytial growth pattern (sheet like) in greater than 75% of tumor area
  - Moderate to marked lymphoplasmacytic infiltrate in the stroma. Predominantly T lymphocytic infiltrate is present
  - Tumor cells with high nuclear grade and indistinct cell borders
  - Noninvasive microscopic circumscription – pushing smooth borders instead of infltrating margins
  - High mitotic rate
Microphotographs

Immunohistochemistry
- Tumor cells are P53 positive and HER2/neu negative tumors
- 90% of tumors are ER negative. Only 10% are ER and PR positive
Treatment and Prognosis
- Good prognosis
- Treatment is modified radical mastectomy
- The only prognostic factor is axillary lymph nodal status.

Robbins and Cotrans: Pathologic basis of diseases.8th edition
Fattaneh A Tavassoli, Vincenzo Eusebi. Tumors of mammary gland. AFIP Atlas of tumor pathology. Series 4
Robin Reid, Fiona Roberts, Elaine Mac Duff. Pathology Illustrated. 7th Edition 2011