All DCIS is considered "stage 0 breast cancer" - or the earliest stage possible. Once DCIS as an early stage cancer is confirmed, it may be given a specific DCIS 'grade' based upon the particular kinds of cells which are growing, the characteristics of their nuclei, and their growth patterns. The lower the grade, the more slowly the cancer cells grow and the more closely they resemble normal breast cells. Based on this information, the pathologist will describe the DCIS as either grade one (low), grade two (medium) or grade three (high).
DCIS differs from Atypical Ductal Hyperplasia in that the atypical cell growth is now disturbing the stroma or supporting-framework cells of the duct, but has not yet penetrated the duct wall. Another way to look at it is that the new cell growth is occuring in a completely unpredictable way. This would suggest that cancer is present and is the cause.
Low and medium grade DCIS implies that the cancer cells are growing at a relatively slow rate. People with low-grade DCIS face an increased risk of invasive breast cancer compared to people without DCIS, but it is unlikely to appear until after five years. However, women with low-grade DCIS are less likely to have a recurrence of the breast cancer or to develop new cancers. Grade I or low-grade DCIS cells appear very much like normal breast cells or atypical ductal hyperplasia cells. Grade II or moderate-grade DCIS cells look less like unaffected cells, and grow faster than normal.
In the image below, malignant cells have completely filled the lumen (empty space) of the duct, but have regular-looking nuclei. This is considered low-grade DCIS. Note that the presence of microcalcifications is not necessarily a malignant indictor for the pathologist.
The image below also shows DCIS, in which malignant cancer cells have partially filled the duct. However there is noticeable variation in the size and shape of the cancer cell's nuclei, with a probable intermediate-grade diagnosis. Also present in the duct are 'crushed-stone' microcalcifications and various bi-products, which would not necessarily increase malignant criteria for the pathologist.
In the high-grade pattern, DCIS cells tend to grow more quickly and the cells look much different from healthy breast cells. High-grade DCIS is indicitive of cancer cells which are growing rapidly,and has the highest risk of becoming invasive breast cancer within the first five years following DCIS diagnosis. High-grade DCIS also poses a significantly increased risk for the cancer to return, and likely within the first five years.
In the image below the malignant cells have once again completely filled the duct, but they also show a significant variation in the size and shape of their nuclei. This tends to suggest a more malignant carcinoma, likely diagnosed as grade III or 'high'. Also present in the duct are evidence of dead cancer cells (necrosis), and 'casting' microcalcifications. However the casting-like microcalcifications are not necessarily a malignant indicator.
A 'cribiform' pattern has gaps between the cancer cells within the duct, with an appearance similar to the 'holes in swiss cheese' or perhaps 'ripples'. A cribiform pattern is consistent with a low or medium grade DCIS.
A "Solid" cell pattern is one in which the cancer cells have completely filled the duct. Sometimes this is called "Comedo" DCIS , which literally means 'plug'. The breast duct is completely plugged by cancer cells. Solid or comedo growth patterns are high grade ductal carcinoma in situ, if there is a corresonding variation in nuclei or evidence of necrosis.
'Necrosis' refers to the remnants and debris from cells that have died. The cancer cells are growing so quickly that some of them don't get enough nourishment, and die. "Comedo necrosis" describes a situation where the entire breast duct is plugged and with dead cancer cells scattered among the live ones. It is categorized as High grade DCIS with high risk of escalation. In the image below the necrosis is seen as the dark regions surrounded by white at the tips of the arrows. The entire upper-right quadrant is "comedo", or a plug.
A 'papillary' DCIS pattern is one arranged in a 'fern-like' pattern within the duct. Unlike the cribform pattern, the papillary has no isolated 'holes' of cancer cells, but they are all connected in a kind of assymetrcal or undulating pattern throughout the duct. If the cancer cells comprising this pattern are very small by comparision, it is often termed "micropapillary". Necrosis and mitiotic figures may be seen in paplillomas for women over the age of 40.
Papillary DCIS may actually present as one of four pattern types. These are a) Cribiform- with a high resemblence to cribiform DCIS but of a larger size b) Tall-hyperchromatic or stratified spindle cell, according to the 'tall' or 'spindle' cell shapes. Stalks are thin, delicate firbrovascular, typically with no myoepithelial cells present. Cells may also have a clear nucleus. c) Compact Columnar, in which the cancer cells are in uniform columns of cells, and d) Transitional cell, which resembles a kind of cancer that can occur in the bladder, but this is rare.
Papillary DCIS comes in many forms and subtle variations, and tends to fall from the intermediate to high-risk grades. Micro-papillary DCIS is now thought to be a highly malignant, dangerous presentation of DCIS, and is of the highest risk. With micropapillary DCIS the ducts are dialated and lined by a stratified population of monotonous cells. The pattern may show small finger-like protuberances with bulbous ends, which may form arches. Micropapillary DCIS is often multifocal and multicentric. When the presentation is pure, it is often considered grounds for mastectomy in hopes of avoiding invasive micropapillary carcinoma.
Complete removal of benign papillomas has shown to dramatically reduce the appearance of subsequent breast cancer. For malignant papillomas or where there is intracystic carcinoma, there is a high rate or recurrence and associated DCIS. A wide surgical removal is usually recommended. Among women, papillary carcinomas account for 1-2% of all breast cancers. most commonly occurring with women in the 62-67 age range.
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