An OnlyFans model fears her M-cup breasts won’t stop growing because of a rare condition.

Pamelia James, 27, of Melbourne in Australia, claims her gigantomastia has caused her to go up four bra sizes — or 31cm (12 inches) — in just one year.

The mother-of-one sought medical help in March for her back, neck and shoulder pain. 

She also noticed her chest was growing rapidly when her most-worn bra no longer fit.

A rare condition called gigantomastia has caused Australian Pamelia J’s boobs to grow four bra cup sizes to an M-cup, and they won’t stop growing (Pictured: Pamelia now)

A doctor suggested her issues were due to the weight of her breasts and referred her for follow-up care.

Miss James, a mother-of-one, was eventually diagnosed with gigantomastia, also called breast hypertrophy or macromastia.

The condition is benign (non-cancerous) but can cause debilitating breast, back, neck and shoulder pain, among other symptoms.

As of 15 years ago, fewer than 110 cases of the condition had ever been published in medical literature. 

The condition caused Miss James’ boobs to grow to an M-cup, with her bust growing from 100cm (39 inches) last January, to 114cm (45 inches) by July and now sitting at 131cm (52 inches).

She said it has left her with massive physical and mental discomfort.

Miss James said her mental health has suffered as a result of the condition as people give her ‘dirty looks’, so she tends to stay at home.

The OnlyFans content creator said: ‘It is very uncomfortable — they are so heavy and I can be in a lot of pain.

In January last year, her bust was 100cm but just seven months later it had grown to 114cm and now Pamelia’s chest measures 131cm – causing her massive physical and mental discomfort (Pictured: Pamelia before the excessive breast growth)

‘At first it was fun and interesting to see how much they were growing, but recently I’ve grown to be uncomfortable and I find myself wishing I had normal-sized breasts.

‘I struggle to find clothing to suit my bust and I end up just wearing oversized t-shirts. There are very limited options for bigger-busted women, especially if you don’t want to have your cleavage on show.

‘I feel very self-conscious when going out in public. If I wear something that is tight on my chest, I notice women giving me looks.

‘I feel like I’m getting dirty looks for having such large breasts so I tend to stay at home — my mental health has suffered from it.’

Annie Turner-Hawkins, a 66-year-old fetish model from the US, holds the Guinness World Record for the largest natural breasts (102ZZZ).

She also has gigantomastia and has spoken out about the struggles of having such large boobs — which weigh 30kg (66lbs) each.

Ms Turner-Hawkins previously said she has to ask herself ‘who is going to attack me today’ when she goes out.

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Annie Turner-Hawkins, a 66-year-old fetish model from the US, also has gigantomastia and holds the Guinness World Record for the largest natural breasts (Pictured: Ms Turner-Hawkins on This Morning in 2011)

Gigantomastia is thought to be caused by a range of factors, including hormonal changes, medications and autoimmune diseases.

Miss James also has polycystic ovary syndrome — abnormal hormone levels that cause irregular periods and for the ovaries to become enlarged. She is undergoing testing to see if the two conditions could be related.

She said her best option is to get a breast reduction, which she hopes to get at some point this year.

She has a seven-year-old son but would like to have another baby before undergoing the surgery.

There is a chance her breasts may grow back to their current size after the reduction but Miss James is looking forward to having some of her discomforts eased.

She has been using the social media site TikTok to share her experience as she hadn’t yet seen people post about gigantomastia.

She hopes sharing her story will encourage people to think twice before passing judgement on her appearance.

Miss James said: ‘The online reaction has been surprisingly positive overall and I’ve had a lot of women sharing their experience with getting a reduction.

‘Of course, you get the odd rude comment.

‘But for the most part, I feel that it’s opened people’s eyes to what gigantomastia is — it is a very rare condition so most people don’t know about it.

‘I’d like people to do research before giving an opinion on the way that I look. It is uncomfortable and it is not easy to have gigantomastia.’