Mucinous Carcinoma of the Breast (Colloid Cancer)
Mucinous carcinoma or mucin-producing carcinoma is a type of invasive ductal breast cancer.
The distinguishing feature of mucinous carcinoma (sometimes called colloid cancer) is the production of mucus. At the cellular level mucinous carcinoma appears as ‘islands’ of malignant cells within ‘lakes’ of mucus. Tumors for this cancer type can grow very large and are often softer to the touch.
Statistically, mucinous carcinoma accounts for approximately 3% of all breast cancers. It is rare in younger women and tends to effect women in their 60’s. For women 75 years or older, mucinous breast cancer accounts for approximately 7% of all tumors.
I just want to let you know that I have created a newer version of this page with more up-to-date material on Colloid Carcinoma.
Mixed and Pure Mucinous Carcinoma
On the whole, mucinous carcinoma of the breast tends to be a low to medium grade, slow-growing carcinoma. However, some variants of the disease are more aggressive than others.
If the histological evaluation reveals that mucinous elements are ‘mixed’ in with the collections of malignant cells, rather than being completely expelled to the surrounding mucous lakes, the prognosis is somewhat less favorable.
A pure mucinous carcinoma contains no mucous within the malignant elements, and this seems to be a more favorable disposition.
Clinical studies demonstrate that the ‘mixed‘ presentation is more likely to metastasize to the lymph nodes. Other studies show that the presence of neuro-endocrine cells may be associated with the less-aggressive, ‘pure‘ carcinoma.
There is also speculation that an ‘alternating pattern’ of malignant cell orientation may lead to a slower tumor growth pattern, due to the ‘bonding’ and containment benefits of the surrounding stroma.
Other considerations and treatment options.
Mucinous carcinoma tends to be highly estrogen-dependent, and HER2/neu negative. It also typically releases a sialic acid called ‘C9-O‘, which is quite easy to spot through histo-chemical analysis.
Mucinous breast carcinoma tends to feature palpable tumors. These tumors are often highly positive for estrogen receptors, but HER2/neu negative. Lymph node metastasis is actually somewhat rare, unless the tumor is ER negative. It has also been suggested that mucinous carcinoma of the breast is more aggressive with when diagnosed in younger women.
Axillary node metastasis is uncommon for smaller tumors
Axillary lymph node metastasis is rare for tumors less than 3cm in diameter, and ‘comedo’ or ‘plugged-duct’ growth patterns are infrequent, occurring in approximately 11% of cases. So for women with “pure” mucinous carcinoma, breast conserving therapies might be a reasonable option. Unless the tumor is larger than 5 cm or invading the local skin, non surgical treatments are quite reasonable.
The outlook for mucinous breast cancer is highly favorable
In terms of prognosis, mucinous carcinoma has a favorable outlook. Women with this diagnosis have demonstrated a 10 year survival rate of 90% or more.
In most cases, mucinous carcinoma does not metastasize to the lymph nodes or to other parts of the body.
Here are some Q&A’s
What is mucinous carcinoma?
This type of cancer is a tumor made up of abnormal cells that float in pools of mucin, a key ingredient in the slimy, slippery substance known as mucus.
What are the signs and symptoms of mucinous carcinoma?
Like other types of breast cancer, mucinous carcinoma may not cause any symptoms at first. Over time, a lump may grow large enough to be felt during breast self-examination or examination by a doctor.
How big is mucinous carcinoma?
The average mucinous carcinoma is about 3 cm, although they can be either smaller or larger than that.
How is mucinous carcinoma diagnosed?
It involves a combination of steps. These include physical examination of the breasts, a mammogram, ultrasound, MRI, and biopsy. Now or after surgery, the tissue should be tested for some other important features of a pure mucinous breast carcinoma. These include hormone receptor positive status, and HER2 negative status.
What is the treatment for mucinous carcinoma?
You and your doctor will work together to analyse ways to develop your treatment plan for mucinous carcinoma of the breast. Treatment plans may include surgery to remove the cancer and in some cases any affected lymph nodes (lumpectomy, total or simple mastectomy), and adjuvant therapy (radiation therapy, hormonal therapy, or chemotherapy)
- Adsay NV, Merati K, Nassar H, Shia J, Sarkar F, Pierson CR, Cheng JD, Visscher DW, Hruban RH, Klimstra DS. (2003) Pathogenesis of Colloid (Pure Mucinous) Carcinoma of Exocrine Organs. Journal of Surgical Pathology. 2003 May;27(5):571-8 https://www.ncbi.nlm.nih.gov/pubmed/12717243
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- Paramo JC, Wilson C, Velarde D, Giraldo J, Poppiti RJ, Mesko TW. (2002) Pure mucinous carcinoma of the breast: is axillary staging necessary? Annals of Surgical Oncology. 2002 Mar;9(2):161-4 https://www.ncbi.nlm.nih.gov/pubmed/11888873
- Rasmussen BB. (1985) Human mucinous breast carcinomas and their lymph node metastases. A histological review of 247 cases. Pathology Research and Practic. 1985 Oct;180(4):377-82. https://www.ncbi.nlm.nih.gov/pubmed/2999736
- Saez C, Japon MA, Poveda MA, Segura DI. (2001) Mucinous (colloid) adenocarcinomas secrete distinct O-acylated forms of sialomucins: a histochemical study of gastric, colorectal and breast adenocarcinomas. Histopathology 2001 Dec;39(6):554-60 https://www.ncbi.nlm.nih.gov/pubmed/11903571
- Tse GM, Ma TK, Chu WC, Lam WW, Poon CS, Chan WC. (2004) Neuroendocrine differentiation in pure type mammary mucinous carcinoma is associated with favorable histologic and immunohistochemical parameters.Mod Pathol. 2004 May;17(5):568-72. https://www.ncbi.nlm.nih.gov/pubmed/15001999
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