I haven't posted before as have mainly just used the forum for information etc, but your post struck a chord with me as am in the same situation.
To give you the short version: Earlier this year my routine smear came back with abnormalities (first time there was something abnormal in 3/4 smear tests),
I was referred for a colposcopy - where the consultant explained that the abnormality was "glandular" which could mean one of a number of things, most of them not cancer or even pre-cancer and he would have a look. He noticed a very slight vessel out of line ver close to the opening of the cervix. Took a biopsy and it came back 2 weeks later as CIN3. When I went in to get the LLETZ treatment, the consultant (a different one) said that she would remove about a cm as it seemed likely that the lesion spotted went further up the cervical canal, given the fact that my smear registered a glandular (and not squameous) abnormality. A few weeks ago I was advised by the clinic that the biopsy taken from the LLETZ had returned a diagnosis CGIN and CIN3. I was pretty unsurprised by this, although was surprised that around 16mm depth had been removed and that the lap report stated that it seemed almost certain that the whole lesion had been removed, but that it wasn't confirmed beyond reasonable doubt. The clinic explained that there were no cancerous cells found, but that as these are precancerous and COULD progress to cancer, they like to be sure etc etc. The consultant had checked the file and my case would be referred to an MDT meeting (not for another month or so). I have to say that she pointed out that even in cases where the margins are 100 per cent clear and they are sure beyond all reasonable doubt, glandular cases are ALWAYS referred (since 2013 I think) to an MDT meeting.... this is now the gold standard in Britain and Ireland...
In terms of what CGIN means, my understanding is not so much that it is more agressive. Although it is possible that I've not been told this! But rather that it is harder for medical staff to actually see what is going on because the cells affected are inside the cervical canal. Because CIN3 etc affects the cells outside, on the face of the cervix, a bit of solution and white marks appear and everything is visible in the microscope. The same is not true with CGIN. The colposcopy nurse explained to me that in the majority of cases CGIN emerges in the Transformation Zone (the bit close to the opening of the cervix) and in my case it is an extension of the CIN3 lesion (indicated by the tiny vessel change) on the outside of the cervix.
Therefore its not a case of aggressiveness/quicker progression etc (again, this is based on my own research and discussion etc with medical staff on my case) but that they have to be sure they have removed it all. I was told that they might do further LLETZ for me to remove any remaining cells, or that they will leave it 3 months or so and then do a test again, one which includes the brush going into the cervix to check for any remaining abnormalities. The cases that tend to be more concerning (and this was explicitly stated to me two or three times by my doctor and nurse) are the ones where smear tests return glandular abnormality results but repeated colposcopy, brushes and lletz show NOTHING at all abnormal. in these cases, it may mean that the cells are either very high up the cervix or originate from elsewhere (more concerning particularly for women over 50 I believe)... So if they have found something high grade on colposcopy and can treat it, this is good news (although it never really feels like it!)
As for a hysterectomy etc, I was told that sometimes they do this if the abnormality is actually cancer, if CIN or CGIN is recurrent, if the woman is older and wants to be on the safe side or where people have had previous gyno problems... In cases of first time abnormalities in particular, especially in young women, many consultants will choose to monitor carefully and keep an eye on any potential pregnancies. I've also not had children, so was worried about this (and to be honest I still am, especially if the MDT meeting decide that I need further treatment!) but I also know that even when women have had cancer in this area or had the cervix removed because of this, pregancy is possible, and medical teams are careful to monitor women in this position.
I hope everything goes well and do try not to worry. I've found it easier in a way since getting the LLETZ results because although I was told it was exremely unlikely that I had cancer, it is always possible that the LLETZ will show something like that and I guess its a worst case scenario. Now I know that my condition is precancerous and is most likely removed, I feel fortunate in many ways that routine smears can prevent the development of invasive disease, but also feel that I can wait a bit more patiently for outcome of MDT meeting.