Answer

Gardner syndrome is an inherited autosomal dominant disorder [1]. The disease spectrum consists mainly of (i) adenomatous polyps of the gastrointestinal tract, (ii) multiple osteomas, (iii) skin and soft tissue tumors including epidermoid cysts and desmoid tumors [2] (Figs. 1 and 2).

Fig. 1
figure 1

3D surface-rendered image demonstrating multiple osteomas of the skull and maxillofacial bones. Note the large osteomas in the angle and condyle of the right mandible

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Fig. 2
figure 2

Osteomas of the wall of the ethmoid sinus are seen with their hyperdense and confluent appearance

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Osteomas arise from the surface of bone and may range in appearance from mild thickenings of the cortex to large masses in the bone, including the skull [1]. Dental abnormalities include impacted or un-erupted teeth, congenitally missing teeth, and supernumerary teeth that may be observed secondary to centrally located osteomas of the mandible present near the roots of the teeth [1, 2]. Lobulated type of osteomas can be large and arise from the cortex most commonly observed at the mandibular angle causing bumps, as seen in this case [1].

Early detection of Gardner syndrome is important because patients can develop malignant transformation of their colonic polyps [1, 3]. The maxillofacial features of the syndrome can precede the development of colonic adenocarcinoma, so it is essential for radiologists to be familiar with the imaging features of Gardner syndrome [3]. The presence of multiple osteomas (more than three) of the skull and abnormal dental findings should alert the clinician to further investigate the possibility of this pre-cancerous condition [3].

Osteomas of the mandible and maxilla along with resultant supernumerary and impacted teeth can be detected in routine panoramic radiograph [3]. CT provides better delineation of the details and extension of the osteomas of the skull and facial bones. Diagnosis of Gardner syndrome necessitates further genetic counseling and close surveillance for malignancies [2]. Osteomas may require excision if they are severely deforming, interfere with daily function, or cause compression of adjacent vital structures Fig. 3.

Fig. 3
figure 3

Large lobulated osteomas displacing parapharyngeal soft tissues

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