This sub type of IDC cancer is also known as colloid carcinoma or mucous tumor. It is quite a rare type of tumor. As the name suggests this mucinous carcinoma is abnormal tumor cells found in pool of mucin. Mucin is the primary component of mucous. Mucous is secreted by many of our vital organs and makes the inner lining of our body cavity. Cancer cells of the breast secrete this mucous containing breast cancer cells. In this cancer the mucous forms a part of the cancer. Together a jelly like timorous growth is seen in the breast and it is known to rarely spread to lymph nodes.
This tumour in “pure” form makes only 2-3% of IBC while about 5% of IBC in addition to other cancerous cells have been known to have a mucinous component. As a percentage only 3% of cancers affecting women, have this carcinoma type.
The highest incidence is seen in older women with an age group beyond 60s.
This tumor due to its components feels like gelatinous water balloon. These on an average are sized at 3cms and on physical examination may feel like fluid filled cysts. There are no obvious symptoms in the intial phases just like any other breast cancer but over time these bumpy cysts like lumps may develop and the breast skin may feel tender.
A soft lump of the cancer cells growth in the breast can be felt in a physical examination of the breast. A mammogram would be done to identify the location of the tumor and rule out evidence for presence of other cancerous growth in the breast. a mammogram usually images a benign looking lump as the edges are not jagged and irregular like other cancers. A small sized cancer might also sometimes get lost in an imaging test in the healthy tissue. Other imaging tests like ultrasound and MRI are done for a better clarification on the size, location and sign of presence of any other cancerous growth.
Biopsy is a conclusive pathological test in which with the help of a small incision cancerous cells are removed for examination under microscope. This gives an accurate detection and diagnosis of the type of cancer which is not possible in mammo, ultrasound and MRI as sometimes healthy tissue is confused with cancerous tissue due to regular and well defined boundary of mucous cancer cells. Open surgical biopsy is the preferred mode inthis type of cancer for removal of cells from site.
On examination it looks like a pool of mucous cells with breast cancer cells floating in it. At times when at least 90% of cells are mucinuous, it is termed a pure” marcunious carcinoma. But it is termed as a mixed mucinuous carcinoma when within this growth there are IDC cells roughly making up more than 10% of the cancer growth. Also in the surrounding tissue sometimes with mucinuous carcinoma other types like DCIS are also found. There are two other features associated with a pure tubular carcinoma which are: hormone-receptor-positive (HR+) status and HER2-negative (HER2-) status. HR+ status is a positive affinity for estrogen hormone receptor (70 - 100%) and a positive affinity for hormone progesterone 60 – 80% times. As regards the second feature of HER2-, these imply the negative affinity of tubular cancers for the receptor for protein HER2-. The good thing about these two features of tubular carcinoma is that with these parameters the tubular carcinomas tend to remain small and stay restricted to the primary breast. These features attribute the growth to be less aggressive and confined. Also there is lower tendency of presence of chromosomal abnormalities usually associated with invasive breast cancers.