When a little girl was about 14 months old, her parents noticed a small, fleshy growth on her right upper eyelid. Over the following months, it slowly grew. The lump sat on the punctum, the tiny opening on the eyelid that drains tears.
When she was evaluated at 18 months, surgeons removed it completely. Lab analysis identified a conjunctival stromal tumor, known as COST, a rare growth first described in 2012. Pathologists and an ophthalmologist at Vanderbilt University Medical Center in Nashville report that she is only the third child known to have been diagnosed with the tumor and the youngest reported to date.
The case report was published online June 11 in the American Journal of Ophthalmology Case Reports and appears in the journal's September 2026 collection. With fewer than 60 cases reported in the medical literature, the tumor is still unfamiliar to many doctors.
A Slow-Growing Lump on a Tiny Drain
According to the full report, the girl had no significant medical history, no previous eye injury and no family history of syndromic conditions. An eye exam showed the growth was not attached to the eyeball.
The location made the case unusual. COST is found most often on the bulbar conjunctiva, the thin membrane covering the white of the eye. This one appeared to involve the punctum instead.
The punctum is the entry point to the eye's drainage system. According to Cleveland Clinic, each eye has two puncta, one on the upper lid and one on the lower, which work like the drain in a sink. Tears flow through them into small channels and eventually drain into the nasal passages.
During surgery, the mass appeared to come from the punctum area. Surgeons removed the nearby part of the punctum along with it but left the rest of the tear drainage system intact. The lesion measured 0.7 by 0.6 by 0.4 centimeters, less than a third of an inch across, and had an ivory color and a gelatin-like texture.
What the Microscope Revealed
Pathologists found a well-defined, polyp-like nodule made of bland spindle-shaped cells, some with pseudonuclear inclusions, along with giant cells whose multiple nuclei formed flower-like patterns called florets. The surface was mostly covered by stratified squamous tissue, with only a small amount of conjunctival lining. Special stains showed the spindle cells were positive for the markers BCL-2 and CD34, a profile consistent with COST.
COST was first described in a 2012 case series as a benign mesenchymal proliferation, a noncancerous growth of connective tissue-type cells. The World Health Organization now classifies it as a fibrous or fibroblastic tumor on a spectrum with ocular surface fibromas, the authors note.
The tumor is estimated to account for less than 0.001% to less than 0.2% of all conjunctival lesions. Its cause is unknown, though researchers suspect it may arise from reactive or inflammatory processes. It has been seen most often in middle-aged adults.
Only Two Children Had Been Diagnosed Before Her
Before this report, COST had been documented in children just twice. The authors argue that doctors should consider it when evaluating a conjunctival lesion in a patient of any age.
They also stress the importance of distinguishing COST from conjunctival myxoma, a different growth with known syndrome associations. A case report on a conjunctival myxoid stromal tumor noted that such tumors could signal undetected systemic conditions, including Carney complex and Zollinger-Ellison syndrome.
A benign label does not always mean a simple course. In a report from Montreal researchers, published in April in the same journal, a 43-year-old man's COST kept returning after three surgeries and responded minimally to radiation. Doctors ultimately removed the contents of his eye socket to keep the tumor from extending into the skull. He has shown no recurrence in the 32 months since. That case is a reminder that the tumor's behavior is still being defined.
No Sign of Recurrence So Far
The toddler is being followed regularly, and there is no evidence that the growth has returned. Longer follow-up will be needed to know her long-term outlook. Because the lump was removed completely and examined in full, doctors were able to confirm the diagnosis rather than rely on its appearance alone.
As a single case report, the study cannot show how common COST is in young children or whether it behaves differently in them than in adults. It does push the youngest reported age for the tumor lower than before.
Many eye complaints in babies have common explanations. Blocked tear ducts, for example, affect 6% to 20% of infants, according to Cleveland Clinic, which also lists growths, both benign and, rarely, cancerous, among the possible causes of blockages. Parents who notice a growing lump on or near a child's eyelid should have it checked by a pediatrician or eye specialist.
Key Questions Answered
What happened to the 18-month-old girl?
Her parents noticed a slowly growing lump on the tear drainage opening of her right upper eyelid. Surgeons removed it, and lab testing identified a conjunctival stromal tumor.
What is a conjunctival stromal tumor?
It is a rare growth first described in 2012 as a benign proliferation of connective tissue-type cells. Fewer than 60 cases have been reported.
Why is this case unusual?
She is only the third child reported with the tumor and the youngest to date. The tumor's apparent location on the punctum was also unusual.
How was it treated?
The lump was completely removed with surgery. She is being followed regularly, with no sign of recurrence so far.
Can this tumor come back?
The toddler has shown no recurrence so far. A separate 2026 report described an adult whose tumor returned repeatedly and required extensive surgery, so its behavior is still being studied.
What should parents watch for?
A growing lump on or near a child's eyelid should be evaluated by a pediatrician or eye specialist.
