Radiological Recognition of Gardner's Syndrome: A Case of Desmoid Tumor, Osteomas, and Colonic Polyposis

Abstract

Gardner's syndrome (GS) is a rare autosomal dominant familial polyposis syndrome characterized by a combination of gastrointestinal and extracolonic manifestations, which include multiple colonic polyps, osteomas, and soft tissue tumors such as desmoid tumors. We report a rare case of a 24-year-old woman who presented with abdominal pain and a palpable abdominal mass. Imaging revealed a mesenteric desmoid tumor, multiple osteomas in the skull and paranasal sinuses, and supernumerary incisors, raising suspicion of GS. Virtual computed tomography colonoscopy and endoscopy showed extensive colonic and duodenal polyposis, and histopathology confirmed adenomatous polyps with dysplasia. The patient underwent surgical resection of the jejunal desmoid tumor and a total proctocolectomy with ileoanal pouch anastomosis. This case highlights the pivotal role of multimodality imaging in the early recognition of GS and its extracolonic manifestations, enabling timely diagnosis and management.

Keywords

colonic polyposis - desmoid tumor - Gardner's syndrome - osteomas - virtual CT colonoscopy

Here, we present a case of a 24-year-old woman with a 10-day history of abdominal pain localized initially to the left lumbar region, radiating to the back. She had a similar episode of lower abdominal pain 2 months prior. There were no associated symptoms such as fever, vomiting, or abdominal distension. On examination, vital signs were stable, and a vague lump was palpated in the left iliac fossa on deep palpation.

The patient was advised to undergo contrast-enhanced computed tomography (CT) of the abdomen for further evaluation. It revealed a well-defined, round-to-oval mesenteric soft tissue lesion in the left abdomen, exhibiting homogeneous enhancement on delayed scans and displacing the bowel loops left laterally. These features were consistent with a benign neoplastic lesion, mesenteric desmoid tumor ([Fig. 1 (a–d)]). Additionally, a small enhancing polypoidal lesion was observed in the distal part of the transverse colon ([Fig. 1 (e, f)]). This raised our suspicion of Gardner's syndrome (GS) and further evaluation was done. Virtual CT colonoscopy and endoscopy further revealed multiple (more than a hundred) subcentimetric sessile polyps throughout the colon, indicative of colonic polyposis ([Fig. 1 (g, h)]).

Figure 1 Axial CT images, (a) (precontrast), (b) (arterial phase) (c) (venous phase), and (d) (delayed phase) showing a well-defined, progressively homogenously enhancing round-to-oval mesenteric soft tissue lesion in the left side of the abdomen, seen displacing the bowel loops in the left abdomen. (e) Axial and (f) sagittal contrast-enhanced CT images, venous phase showing a well-defined, enhancing small polypoidal lesion in the distal part of the transverse colon (white arrows). Virtual CT colonoscopy (g) and endoscopic colonoscopy (h) images showing multiple colonic polyps. Postoperative histopathological specimen showing excised desmoid tumor and small colonic polyps (i). CT, computed tomography.

X-ray and CT of the paranasal sinuses showed multiple osteomas along the posterolateral aspect of the left maxillary sinus and other small osteomas in the bilateral ethmoidal air cells ([Fig. 2 (a–c)]). Impacted/supernumerary central incisors were also noted with metallic artefact ([Fig. 2 (d–f)]). On leading questions, the patient revealed a history of spontaneous loss of central incisors and an artificial tooth implant.

Figure 2 Frontal X-ray of paranasal sinuses (a) showing well-defined radio-opacity overlying the left maxillary sinus (white arrow). Axial CT images of paranasal sinuses in bone window (b, c) showing osteoma along the posterolateral aspect of the left maxillary sinus and small osteomas in the bilateral ethmoidal air cells (white arrows). Coronal CT image (d) showing supernumerary/impacted central incisors with an artificial central incisor. Volume rendered images of skull (e, f) demonstrating multiple small bony outgrowths along the frontal and parietal bones suggestive of skull vault osteomas. CT, computed tomography.

CT scan of the skull revealed multiple small bony outgrowths along the frontal and parietal bones suggestive of skull vault osteomas, better visualized on volume-rendered images ([Fig. 2 (e, f)]). Ultrasound of the thyroid was normal.

Colonoscopy further confirmed the diagnosis and presence of multiple colonic polyps ([Fig. 1 (h)]). Upper gastrointestinal endoscopy revealed similar findings of multiple subcentimetric sessile polyps in the duodenum. Biopsies from the colonic polyps showed adenomatous changes with mild dysplasia, while duodenal biopsies revealed chronic duodenitis.

The patient underwent exploratory laparotomy, during which the mesenteric mass was found to be attached to the jejunum, so resection of about 100 cm of jejunal loop was performed, with side-to-side jejunojejunal anastomosis, along with a total proctocolectomy and end-to-end ileoanal pouch anastomosis. A diversion loop ileostomy was also created.

The excised specimen ([Fig. 1 (c)]) underwent histopathological examination, uncovering the abdominal tumor as a desmoid tumor and identifying the largest colonic polyp as a tubulovillous adenoma with low-grade dysplasia.

The constellation of radiological, endoscopic, and histopathological findings was consistent with GS. This diagnosis is supported by the presence of multiple colonic and duodenal polyps, along with extracolonic manifestations such as mesenteric desmoid tumor, paranasal and skull osteomas, and supernumerary central incisors.

GS is an autosomal dominant disorder first described by Gardner and Richard in 1953 and is a spectrum of familial adenomatous polyposis (FAP) since in both the condition adenomatous polyposis coli (APC) gene mutations are observed, a tumor suppressor gene located on chromosome 5q21-22.[1]

It can present at any age between 2 months and 70 years with either colonic or extracolonic manifestations. Our case presented at 24 years with abdominal pain and a lump in the abdomen.

GS is mainly a triad of multiple colonic polyps, osteomas, and any mesenchymal tumor. The gastrointestinal manifestations of GS include colonic adenomatous polyps (tubular, villous, tubulovillous), gastric and small intestinal adenomatous polyps (12% of patients), and periampullary carcinomas (2% of patients).[2] Polyps start appearing at around puberty but are usually diagnosed around the third to fourth decade of life.

Osteomas are seen in about 50% cases of GS, and they appear earlier than polyps. It mainly involves the mandible, maxilla, and skull. However, osteomas affecting long bones have also been reported.[2] Osteomas are benign bone tumors commonly associated with GS and may aid in its early recognition.[3]

The following soft tissue mesenchymal tumors can be present in this condition: fibromatoses, epidermoid cysts, sebaceous cyst, duodenal tumors, ampullary carcinoma,[3] [4] papillary thyroid carcinoma, and other abnormalities such as impacted/supernumerary or unerupted teeth, odontomas and dentigerous cysts, and retinal pigmentation abnormalities. The incidence of desmoid tumors, a nonencapsulated, locally invasive type of fibromatosis, is notably higher in patients with GS, ranging from 17 to 29%. In contrast, the occurrence of desmoid tumors in the general population is significantly lower, estimated at only 0.03%.[3]

Radiologists should remain vigilant for extracolonic manifestations, as they may precede gastrointestinal symptoms and prompt further evaluation for underlying polyposis syndromes.

The radiological findings in this case play a pivotal role in confirming the diagnosis of GS and guiding subsequent management. Virtual CT colonoscopy helped us confidently diagnose the condition.

The World Health Organization (WHO) has listed three clinical scenarios as diagnostic criteria for GS: (1) 100 or more colorectal polyposis, (2) APC gene germline mutation, and (3) a family history of FAP, and at least one epidermoid cyst, osteoma, or desmoid tumor.[5] Our patient met the first and third criteria of the WHO.

Radiological surveillance is essential for monitoring polyp burden and guiding endoscopic interventions to prevent malignant transformation.

Patients with GS, or their relatives, should undergo surveillance programs, including large bowel and upper gastrointestinal tract surveillance.[2]

In conclusion, imaging plays a crucial role in the early diagnosis and management of GS. Radiologist should be vigilant when they encounter any of the above-described soft tissue tumors and osteomas, especially in younger patients, as the extracolonic findings manifest before the colonic polyps in GS. Imaging modalities such as CT and their advanced applications can help us in picking up these sinister abnormalities and in early diagnosis of GS. This facilitates timely intervention and improves patient prognosis.

Teaching Points

• Osteomas of the skull/paranasal sinuses and supernumerary/impacted teeth may occur before gastrointestinal symptoms and should raise suspicion for GS.

• Detection of intra-abdominal desmoid tumor, especially in young patients, warrants evaluation for an underlying polyposis syndrome.

• Role of multimodality imaging—CT, virtual colonoscopy, and endoscopy together help assess both gastrointestinal polyposis burden and extracolonic manifestations, guiding surgical planning.

• Identifying GS before malignant transformation of polyps allows timely colectomy and helps in improving patient prognosis.

Conflict of Interest

None declared.

• References

• 1 Olaopa OI, Dada AA, Soneye OY. et al. A rare case of Gardner syndrome in an African adult male: a case report. Clin Case Rep 2024; 12 (04) e8735
• 2 Fotiadis C, Tsekouras DK, Antonakis P, Sfiniadakis J, Genetzakis M, Zografos GC. Gardner's syndrome: a case report and review of the literature. World J Gastroenterol 2005; 11 (34) 5408-5411
• 3 Magid D, Fishman EK, Jones B, Hoover HC, Feinstein R, Siegelman SS. Desmoid tumors in Gardner syndrome: use of computed tomography. AJR Am J Roentgenol 1984; 142 (06) 1141-1145
• 4 Charifa A, Jamil RT, Zhang X. Gardner syndrome. [Updated October 25, 2022]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022
• 5 Yang D, Zeng X, Lv Y, Liao W, Tang S, Jiang J. Gardner syndrome with a giant mass in the thoracic cavity: a case report and analysis of the related complications. Int J Clin Exp Pathol 2020; 13 (08) 2158-2162

Publication History

Article published online:
02 December 2025