Medical Oncologist
CION Cancer Clinics
Signs of APC outside the bowel: teeth, eyes and bone | CION Cancer Clinics
Some people with an APC fault have signs outside the bowel, such as extra teeth, harmless patches at the back of the eye, small bony lumps or skin cysts. Most cause no illness. They matter because they can point a family towards FAP early. This page explains each feature, how it is checked, and which signs outside the bowel do need regular follow-up. At CION Cancer Clinics, our oncologists explain what a gene result means for you and your family, and plan the checks that follow.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- Why does an APC fault show up in teeth, eyes and bone?
- Which features outside the bowel are most common?
- How are these features checked in a carrier?
- What do the medical names for these features mean?
- Which features are harmless, and which need regular checks?
- What this page cannot tell you
- Four things families believe about these features, and what is true
- Common questions about teeth, eye and bone signs of FAP
The short answer
Why does an APC fault show up in teeth, eyes and bone?
An APC fault is present in every cell of the body, not only the bowel. That is why some people with FAP also have extra teeth, small bony lumps, skin cysts or harmless patches at the back of the eye. Most of these cause no illness at all.
Harmless, but useful clues
These features are called extra-colonic, meaning outside the large bowel. The teeth, eye and bone signs rarely need treatment. Their value is as a clue. A dentist or eye doctor who notices them can prompt a family to ask about bowel polyps years before any symptom appears.
Not every feature is harmless
An APC fault also raises the chance of problems in the upper gut, the thyroid and the tummy wall. Those need planned checks and are covered on their own pages. This page is about the quieter signs, what they look like, and what they do and do not tell you.
Having one of these signs does not change your bowel risk. The APC fault itself sets that.What people notice
Which features outside the bowel are most common?
Some people with FAP have several of these, some have one, and many have none. None of them predicts how many polyps you will have.
Eyes
Flat, dark patches on the retina, the light-sensitive layer at the back of the eye. They are present from birth and do not affect sight. Only an eye doctor looking through a dilated pupil will see them.
Teeth
Extra teeth, teeth that never come through the gum, or missing adult teeth. Some people have small lumps of tooth tissue in the jaw that show up only on a dental X-ray.
A dentist is often the first person to spot FAP.Bone
Small, hard, painless bony lumps, most often on the jaw or skull. They are not cancer and rarely grow much. Some people have them removed for appearance or if they get in the way of dentures.
Skin
Firm cysts under the skin of the face, scalp, arms or legs.
What makes them stand out
- Several at once, not a single cyst
- Appearing in childhood, before puberty
- Returning after removal
Not sure whether this applies to you?
Ask an oncologistHow they are found
How are these features checked in a carrier?
An eye examination
Drops widen the pupil and an eye doctor looks at the retina. It takes a short visit and does not hurt, though your sight may be blurred for a few hours. Arrange someone to take you home.
A full dental X-ray
One wide X-ray shows every tooth and both jaws. It picks up teeth that have not come through, extra teeth and small bony lumps that a mouth examination would miss.
A look at skin and bone
Your doctor checks the scalp, face and limbs for cysts, and the jaw and skull for bony lumps. Tell them about any lump you have had removed in the past.
Deciding what, if anything, to do
Most findings need nothing more than a note in your file. Anything unusual, such as a fast-growing lump, is sent for a closer look. The focus of your care stays on the bowel, stomach and thyroid checks.
On your report
What do the medical names for these features mean?
- CHRPE
- Short for a long name meaning a thickened patch of the retina's pigment layer. It is the flat eye patch described above, and it is harmless.
- Osteoma
- A small, hard lump of normal bone. It is not a cancer and does not spread.
- Supernumerary tooth
- An extra tooth, beyond the normal set. It may sit hidden in the jaw.
- Odontoma
- A small lump of tooth tissue inside the jaw. It is usually found by chance on an X-ray.
- Epidermoid cyst
- A slow-growing sac under the skin filled with soft material. It is common in everyone, but more common and earlier in FAP.
- OPG
- The wide dental X-ray that shows all the teeth and both jaws in one picture.
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Side by side
Which features are harmless, and which need regular checks?
Usually harmless
Needs planned checks
Flat patches at the back of the eye
Polyps in the stomach and the first part of the small bowel
Extra or hidden teeth
Lumps in the thyroid gland in the neck
Bony lumps on the jaw or skull
Desmoid growths in or behind the tummy wall
Skin cysts on the face, scalp or limbs
Liver checks in very young children, if advised
Being straight with you
What this page cannot tell you
It cannot tell you whether a lump, cyst or tooth problem in your family is linked to APC. Only a genetic test, guided by a counsellor who has drawn your family tree, answers that. What your specific variant means is a question for the counsellor who ordered the test.
It cannot replace an examination
A photograph sent on WhatsApp is not enough to judge an eye patch or a bony lump. The features look different from person to person, and some ordinary findings look similar. An eye doctor, a dentist and your oncologist each see a different part of the picture.
Who this does not apply to
Most people with a single extra tooth, one skin cyst or a small bony lump do not have FAP. These are common on their own. They matter only alongside bowel polyps, a known APC fault in the family, or several features together at a young age.
If a dentist has asked about bowel polyps in your family, take that question seriously and ask your doctor.Commonly believed
Four things families believe about these features, and what is true
"The eye patches will make my child go blind."
They do not affect sight. They are present from birth, stay the same and need no treatment. Their only importance is as a sign that the family may carry an APC fault.
"A bony lump on the jaw is a bone cancer."
The bony lumps linked to FAP are made of normal bone. They do not spread and do not turn into cancer. Any lump that grows quickly or hurts should still be checked.
"No teeth or eye signs means no FAP."
Many people with FAP have none of these features. Their absence tells you nothing about the bowel. Only a genetic test or a colonoscopy answers that question.
"Removing the cysts and lumps removes the risk."
The fault is in every cell, so removing a cyst or a bony lump does not change bowel risk at all. Bowel and upper gut checks carry on exactly as planned.
Questions we are asked
Common questions about teeth, eye and bone signs of FAP
My dentist found extra teeth. Should I worry about FAP?
Extra teeth on their own are fairly common and usually mean nothing more. It is worth thinking about FAP if there are also bony lumps in the jaw, several skin cysts, or a relative with bowel polyps or bowel cancer at a young age. If so, mention it to your family doctor.
Can an eye test show whether my child has inherited APC?
Before genetic testing existed, eye patches were used as a rough clue within some families. Today a blood test for the family's known APC fault gives a clear answer, while an eye examination cannot. The eye check may still be done, but it does not replace the gene test.
Do the bony lumps need to be removed?
Usually not. They are removed only if they cause discomfort, affect how the face looks, or get in the way of dental work. A maxillofacial or dental surgeon can advise. Removing them does not change any other part of your FAP care.
Can dental problems from FAP be treated normally?
Yes. Extra or hidden teeth are managed the same way as in anyone else, with extraction or orthodontic work where needed. Tell your dentist you have FAP, especially before jaw surgery, so a full X-ray is taken first and bony lumps are not a surprise.
Is Gardner syndrome a different condition?
Gardner syndrome was the older name used when FAP came with bony lumps, skin cysts and desmoids. It is now known to be caused by the same APC faults. Doctors treat it as part of FAP and the bowel and upper gut checks are the same.
Do these features mean my FAP is more severe?
Not in a simple way. Some features are more common with faults in certain parts of the gene, but having eye patches or extra teeth does not tell you how many polyps you will develop. Your colonoscopy findings guide your care, not these signs.
Should my children have eye and dental checks?
If a child has been tested and carries the family's APC fault, a dental X-ray and an eye check may be offered as part of their care. If the child tested negative, they need no extra checks. Ask your counsellor about the right timing for testing itself.
Are these checks available near my district?
Dental X-rays and dilated eye examinations are widely available in district towns across Telangana. You can usually have them done close to home and bring the reports to your oncology appointment. The bowel and upper gut checks are the ones that need a specialist centre.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Sources
- GeneReviews (NCBI) — APC-Associated Polyposis Conditions
- MedlinePlus Genetics — Familial adenomatous polyposis
- MedlinePlus Genetics — APC gene
- National Cancer Institute — Genetics of Colorectal Cancer (PDQ)
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
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