EASTENDERS’ Sam Mitchell is set to be diagnosed with breast cancer this December after returning to Walford.

The troublemaker portrayed by Kim Medcalf makes the heartbreaking discovery in upcoming EastEnders scenes.

Sam finds a lump in her breast but is terrified to go to the doctors.

Eventually, her erratic behaviour alerts her family that something is wrong.

Jack, Denise and Phil manage to get Sam to open up to them and convince her to get the lump checked.

Her worst fears are confirmed when she is diagnosed with cancer.

However, thanks to the intervention of her family doctors give her a ray of hope, telling her they caught the cancer early.

Sam is booked in for surgery to get the lump removed.

She is set to make a full recovery when she has the lump removed via a lumpectomy in scenes set to air in the New Year.

BBC bosses hope the storyline will highlight the importance of going for life-saving medical checks when changes noticing in your body.

Script writers are also working with charity Breast Cancer Now on the emotional scenes.

The Sun first revealed earlier this month that the glam EastEnders star was returning for an explosive Christmas storyline.

Actress Kim is back to portray Grant and Phil’s feisty sister.

Sam’s return also hinges on her rivalry with another of this year’s comeback characters, Zoe Slater.

Sam and Zoe’s friendship fractured over “Dirty Den” Watts’s murder in 2005 in a shocking storyline which saw Zoe flee Walford.

Now, 20 years on, the duo will be forced to come to terms with their past.

An insider said: “Walford has changed immensely since Sam left, most notably with enemy and ex-murder accomplice Zoe Slater now residing there.

“Zoe and Sam have not seen each other for over 20 years and as the enemies come face-to-face, only time will tell if the pair are willing to put their troubles aside, or if Sam has an ulterior motive.”