**Core Concept**
GARDNER syndrome is a rare genetic disorder characterized by multiple intestinal polyps, osteomas, and other benign tumors, often associated with mutations in the APC gene. It is a variant of Familial Adenomatous Polyposis (FAP), with additional features such as desmoid tumors, dental abnormalities, and skin and soft tissue tumors.

**Why the Correct Answer is Right**
GARDNER syndrome is a distinct clinical entity that includes a range of extraintestinal manifestations, but the specific features that define it are the presence of osteomas, skin and soft tissue tumors, and dental abnormalities. These features are not typically seen in other polyposis syndromes, and the presence of multiple intestinal polyps is a key component of the diagnosis. The APC gene mutation is a critical factor in the development of these tumors.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because osteomas are a hallmark feature of GARDNER syndrome, and their presence is a key diagnostic criterion.
**Option B:** This option is incorrect because desmoid tumors are also a characteristic feature of GARDNER syndrome, and their presence can be used to support the diagnosis.
**Option C:** This option is incorrect because gastrointestinal polyps are a fundamental component of GARDNER syndrome, and their presence is essential for making the diagnosis.
**Option D:** This option is incorrect because this is the correct answer, and it does not come under GARDNER syndrome.

**Clinical Pearl / High-Yield Fact**
When considering a diagnosis of GARDNER syndrome, it is essential to look for the characteristic combination of multiple intestinal polyps, osteomas, skin and soft tissue tumors, and dental abnormalities, as these features are not typically seen in other polyposis syndromes.

**Correct Answer: D.