Dr. Jennifer Arnold and Bill Klein
12/06/2013 AT 08:00 AM EST
Jen Arnold, star of the hit TLC series The Little Couple
, is battling a rare form of cancer.
The Houston-based neonatologist, 39, and her husband Bill Klein, 38, are parents to son Will
, 3, whom they adopted from China, and daughter Zoey
, 2, whom they recently brought home from India.
But what should have been a time of joy and celebration for the reality stars has been bittersweet, as Arnold reveals in an exclusive statement to PEOPLE.
"I have recently been diagnosed with a rare type of cancer and am currently undergoing treatment, including surgery and chemotherapy.” Arnold says.
"I am very fortunate as the prognosis is good. While there is never a good time to get news like this, getting it just as we are building our new family is tough in many ways ... But being surrounded by the love of my husband and our two beautiful children is actually in many ways giving me the strength to fight it even stronger."
No further details about the type of cancer Arnold is facing are being released at this time.
Arnold and Klein have been reality stars since a TV special about their wedding, The Little Couple: Just Married
, became a sensation for the network.
Since then, millions of viewers have watched Arnold and Klein, an entrepreneur who runs Rocky and Maggie's Pet Shop
in Houston, build their dream home, struggle with fertility and surrogacy issues
, and ultimately, expand their family with the adoption of Will and Zoey.
"For a lot of people, loss tears them apart," Arnold told PEOPLE earlier this year. "In general, we are pretty tough people. I feel very lucky and fortunate to have the wonderful life I have. We are good at putting things in perspective because of our life experiences. I am not a person to give up when something is important. We feel so lucky to be parents."
Certainly, Arnold, who has had approximately 30 procedures and surgeries related to her type of dwarfism, isn't one to shy away from a fight.
"Jen has achieved so many great things," Klein told PEOPLE earlier this year. "We are so in love with each other and supportive of each other that we are going to be ok. Few people are so lucky to have what we do, from the moment you meet that one person and everything that you do together, everything that you add to that relationship is exciting as well. We are up for challenges."