Metaplastic breast carcinoma

Metaplastic breast carcinoma (MBC), also known as spindle cell carcinoma of the breast (SpCC), is a rare form of primary breast malignancy and accounts < 5% of breast carcinomas.

These are scarce lesions, rarely seen in general radiology practice. The lesions usually present as mass in postmenopausal women. The mammogram shows a lesion that is dense and has both smooth, defined margins and spiculated edges. The ultrasound images show mixed echogenicity lesions taller or tall as broad.

Patients are commonly older than 50 years, with average age at diagnosis ~55 years. 

These lesions present as a palpable mass lesion (often rapidly growing 1,3) in postmenopausal women. Axillary node involvement at the time of diagnosis is uncommon.

These lesions are considered ductal carcinomas that undergo metaplasia to a glandular growth pattern. There are five variants:

  • matrix producing carcinoma of breast
  • squamous cell carcinoma of breast
  • spindle cell carcinoma of breast
  • carcinosarcoma of breast (the rarest primary breast malignancy)
  • metaplastic carcinoma of breast with osteoclastic giant cells
Histology

These lesions have pathological features of both carcinoma and sarcoma. There is a mixture of glandular epithelial elements and mesenchymal malignant elements. The spindle cell component in 98% of SpCC is immunoreactive for keratin.

Genetics

Phyllodes tumours and sarcomas are usually negative for p63 expression. In metaplastic carcinoma, the sensitivity for p63 is 86.7% and the sensitivity is 99.4%.

Mammography

On a mammogram these are usually rapidly growing lesions that are large/palpable at the time of diagnosis. Mean diameter at the time of diagnosis is 4.2 cm. The lesions are rounded densities on mammography with margins that are both well defined and smooth and spiculated. Calcification is very rare. 

Ultrasound

On ultrasound the lesions are round to ovoid, may be microlobulated, with solid and cystic components related to haemorrhage or necrosis. Most lesion have well defined margins 3.

Breast MRI
  • T2: often displays very high signal 2

Local recurrence generally not ominous and is fatal in ~30% of cases.

Breast imaging and pathology
Share article

Article Information

rID: 23332
System: Breast
Section: Pathology
Synonyms or Alternate Spellings:
  • Metaplastic carcinoma of the breast
  • Metaplastic carcinoma of breasts
  • Metaplastic cacinoma breast (MCB)
  • Metaplastic carcinoma of the breasts
  • Spindle cell carcinoma of breast
  • Metaplastic carcinoma of breast

Support Radiopaedia and see fewer ads

Cases and Figures

  • Drag
    Case 1: ultrasound
    Drag here to reorder.
  • Drag
    Case 1: mammogram
    Drag here to reorder.
  • Drag
    Case 2: ultrasound
    Drag here to reorder.
  • Drag
    Case 2: mammogram
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.