Atypical Lobular Hyperplasia

I'm so sorry you're going through this.  Its scary to get a new diagnosis because you don't know how this will affect the rest of your life.  Many things about ALH are unknown, but ALH alone is not a Huge risk factor for breast cancer.  **If** you have a BRCA gene mutation (see below), that would be a far greater risk for breast cancer than would your ALH.

It is a good move to be referred to a breast surgeon.  This does NOT mean you are definitely committing yourself to mastectomies.  I went to a breast surgeon after my core biopsy revealed classic LCIS, which is a step closer to breast cancer than ALH, and LCIS may confer about twice the risk as ALH. This breast surgeon scheduled a surgical excision for me.  This is not to remove my LCIS (which normally occurs in many places in a breast), but to make sure there isn't something worse in the vicinity.  They called my excision a proceedure to 'verify the diagnosis of LCIS'. 

My breast surgeon also referred me to a genetic counselor, who is the person who evaluates family history.  This was to evaluate whether or not I would be a candidate for genetic testing.  These are the general guidelines on who is in the largest category of people to appropriately get tested for BRCA 1 or BRCA2, which is by far the most common known single inherited gene enzymes involved in breast cancer. http://www.uspreventiveservicestaskforce.org/uspstf05/brcagen/brcagenrs.htm#clinical  If you have unusual family patterns, such as only males in a certain generation, or an only child in some generation, then that may affect the decision on whether or not to get tested.  Testing is expensive, but if you have an appropriate family history, then sometimes insurance covers it.  The most prominent cancers involved in a BRCA mutation are breast and ovarian, but there may be a small association with other cancers. There are other single gene mutations that increase one's chance of breast cancer, though they are much less common.  There are also families that have lots of breast cancer in their family that have no known gene mutation.  Even though my family has more than its share of cancer, the genetics counselor found I had about a 2% chance of having a BRCA mutation, about the same as an 'average' person of Ashkenazi Jewish heritage.  Since I'd have to pay for the testing myself, I opted to not be tested.

Most places encourage a certified genetics counselor.  These are normally found at major institutions.  http://www.facingourrisk.org/index.php 

If your sister had a breast removed due to breast cancer, then information whether or not she was tested for a BRCA mutation would be important.  They normally first try to test the person in the family who has breast cancer, of course if they are still living.  The BRCA test is a simple blood sample.  ALH by itself is not considered breast cancer (nor is LCIS, in spite of its name).

When I was first diagnosed, it felt like I was on a speed course about breast cancer. There are a lot of women here who are in a similar situation as you.  You will probably have lots of choices to make, including whether or not to get BRCA tested and how to handle your ALH.   You and your doctor will decide whether or not to have a surgical excision (unless you have already had one).  Usually there is no huge rush clinically to make any of these decisions.  But I was very anxious and it took me many years to feel more comfortable about my situation.

If I went through the whole process again, I think I would have been good to know how little they actually know about ALH or LCIS. (I have ALH too.)  Whether or not you choose to get BRCA tested, your genetics counselor will be an excellent person to get the 'real deal' about your chances for breast cancer.  But do know that if you do not have a family history that gives you a high risk for breast cancer, and if you have not been treated with chest radiation (such as having Hodgkin's disease), the subject of breast cancer risk evaluation is very much in its infancy.  This means unless you have a severe family history for breast cancer or personal history of lymphoma, the numbers that your doctors give you are rough, rough estimates: I have been given numbers between 10% lifetime risk and 50% lifetime risk, and one calculator gave me a 90% risk. (I'm sure the 90% figure is totally wrong.)

Whatever path you choose to take, there are people here who will support you every step of your journey.