Gardner syndrome is a variant representing one end of the spectrum of a condition called familial adenomatous polyposis (FAP). It is characterized by the presence of numerous intestinal polyps, most commonly adenomas, associated with extracolonic features such as osteomas, fibromas, epidermoid cysts, dental abnormalities, fibrous dysplasia of the skull, and desmoid tumors. Desmoid tumors are tumors arising from the connective tissue that may behave aggressively though they are histologically benign, hence the term “agressive fibromatosis”. Gardner syndrome is a genetic condition with an autosomal dominant pattern of inheritance whose gene defect is located on chromosome 5. However, a few cases numbering approximately 20-30% may represent new mutations.
The clinical presentation of Gardner syndrome varies and often leads to a delay in diagnosis. The extracolonic manifestations may present earlier than gastrointestinal (GI) symptoms, whose detection is critical if appropriate treatment is to be given.
The presence of polyps in the colon may produce signs and symptoms such as rectal bleeding and diarrhea, with exhaustion and fatigue developing due to the associated malnutrition. If obstruction in the GI tract occurs, vomiting, obstipation, peritonitis, and other signs of sepsis may occur. Polyps in other areas of the GI tract may produce different symptoms. Gastric polyps can cause epigastric pain or bleeding, whereas polyps in the duodenum may cause bleeding, pain, or jaundice due to the obstruction of bile flow.
Extracolonic manifestations present in Gardner syndrome lead to a multitude of symptoms . Epidermoid cysts may produce cosmetic defects, and dental abnormalities may cause jaw or teeth pain. Desmoid tumors may cause bleeding or obstruction based on their location. Osteomas, a requirement for the diagnosis of Gardner syndrome, may occur in several locations such as the mandible (most common), skull, paranasal sinuses, or long bones .
Epidermoid cysts develop in 50 to 60% of patients with Gardner syndrome and may be present on the scalp, face, or extremities . Majority of patients presents with colonic polyps (villous, tubular, or tubulovillous). Gastric or intestinal polyps may also occur in 12% of patients, as well as periampullary carcinomas in 2% of them .
An ocular manifestation commonly associated with Gardner syndrome is congenital hypertrophy of the retinal pigmented epithelium (CHRPE), which are teardrop-shaped lesions located in the midperiphery of the fundus. CHRPE is a sensitive marker for Gardner syndrome, as it has been found to absent in colonic polyposis but is present in some variants of FAP.
Laboratory evaluation of Gardner syndrome requires several investigations of the organs or organ systems involved in this condition. Peripheral leukocytes are used to evaluate the presence of an APC gene mutation. In addition to imaging studies to detect the presence of extracolonic malignancies such CT scan of the whole abdomen and pelvis and ultrasound of the thyroid gland, complete blood count (CBC), carcinoembryonic antigen testing, and liver function tests may also be requested to detect possible metastasis. Osteomas can be visualized through panoramic dental radiographs, chest X-rays, long bone radiographs, and skull radiographs. Slit-lamp examination and indirect ophthalmoscopy is required to detect CHRPE. Colonoscopy provides direct visualization of the polyps in the colon. Esophagoduodenoscopy (EGD) may be performed to detect the presence of gastric or duodenal polyps.
Gardner syndrome may be treated both surgically and pharmacologically. Surgical treatment is the definitive treatment for the disorder and includes several options:
Pharmacologic treatments for Gardner’s syndrome include nonsteroidal anti-inflammatory drugs (NSAIDs), which may be given alone or in combination with tamoxifen . Cytotoxic chemotherapy using doxorubicin and dacarbazine may be initiated in order to reduce polyp formation following colectomy and may be used for patients with unresectable disease that does not respond to endocrine therapy, steroids, or NSAIDs  . CHRPE does not produce any symptoms and does not require treatment.
The number of polyps is associated with the risk for cancer development in patients with Gardner syndrome. This risk is 2.3 times greater for patients with more than 1,000 polyps compared to those with fewer than 1,000, independent of age .
Surgical management is an important factor in survival, as patients older than 45 years old who do not undergo surgical treatment have a 5-year survival rate of 0%. Conversely, the 5-year survival rate for patients who undergo proctocolectomy and mucosectomy with ileal pouch-anal anastomosis (IPAA) is almost 100%. The 20-year recurrence rate with total colectomy is 30%, whereas the recurrence rate at 30 years is 45% after total colectomy with ileorectal anastomosis (IRA).
Long-term control of colorectal tumors is possible with adequate screening. However, the presence of desmoid tumors may significantly affect the survival and quality of life of Gardner syndrome patients.
FAP is a genetic disorder comprising of different disease entities, one of which is Gardner snydrome. The different genetic defects associated with FAP are:
In addition, mutations in the MYH gene accompanied by environmental or lifestyle factors such as diet, smoking, and exercise may also play a role in the etiology of Gardner syndrome . However, the most common genetic defect associated with Gardner syndrome is a mutation in the APC gene located in chromosome 5. Although this disease is dominantly inherited, approximately 25% of patients with Gardner syndrome have no family history of the condition .
FAP can occur in one individual for every 7,500 births through an autosomal dominant inheritance in approximately 80% of patients, with the remaining 20% representing new or spontaneous mutations. This condition primarily affects the left colon, but the right colon may be the one primarily involved in attenuated FAP.
Gardner syndrome, on the other hand, has a lower incidence than FAP and is present in one individual for every 14,025 live births  and has a uniform worldwide distribution . The polyps associated with Gardner syndrome typically develop during adolescence and may undergo malignant progression in the third and fourth decade of life.
The manifestation and severity of Gardner syndrome depends on the point at which the APC gene mutation occurs, usually on the short arm of chromosome 5 (5q21-q22) . There have been more than 1,400 different mutations reported, all of which lead to the development of colonic polyps and to the variability of the extracolonic manifestations seen in Gardner syndrome .
The combination of intestinal polyposis and hard and soft tissue tumors  such as osteomas, dental abnormalities, epidermoid cysts, and desmoid tumors characterizes a condition known as Gardner syndrome. It is a genetic disease with an autosomal dominant pattern of inheritance, and affected individuals have a 50% chance of passing the condition to their offspring. Gardner syndrome is considered a variant of (familial adenomatous polyposis) FAP and is commonly associated with a mutation in the adenomatous polyposis coli (APC) gene located in chromosome 5 .
Untreated intestinal polyps associated with Gardner syndrome demonstrate a high risk for malignant progression. Patients with this disease are also at a higher risk of developing FAP-related malignancies in the liver, bile ducts, pancreas, thyroid gland, adrenal gland, or the central nervous system. No treatment is currently available for Gardner syndrome, though management options may reduce the risk of cancer development.
Gardner syndrome is a rare genetic disorder characterized by the presence of benign (non-cancerous) growths called polyps in the large intestine. It is a variant of a condition known as familial adenomatous polyposis and causes the growth of tumors in other areas of the body such as the skull, jaw, or skin. Gardner syndrome is an inherited genetic condition, and having a parent with this disorder increases your chances of having the same condition. Patients with this syndrome are at a greater risk for developing colon cancer, and treatments for Gardner syndrome are directed towards preventing this outcome. Part of the treatment involves close monitoring of the polyps to ensure that they do not become malignant. The outcome of the disease varies according to the severity of the condition and the effectiveness of the treatment.