CT of intraabdominal desmoid tumors: Is the tumor different in patients with Gardner's disease?

OBJECTIVE. A retrospective study of abdominal CT scans of patients with proved intraabdominal desmoid tumors was done to determine if any objective characteristics exist to differentiate desmoids related to Gardner's syndrome from isolated desmoids. Because the desmoid tumors of Gardner's syndrome can predate the diagnosis of Gardner's syndrome, it would be helpful to know which patients with desmoids need careful follow-up studies as well as initial workup for Gardner's syndrome and all its ramifications. Also, it would be important to differentiate benign from malignant desmoids associated with Gardner's syndrome. It was hoped that the location, enhancement characteristics, and/or the presence or absence of infiltration might be of value. We were interested in noting if, over time, the growth characteristics of desmoids found in Gardner's syndrome were different from those of isolated desmoids. MATERIALS AND METHODS. We reviewed 101 abdominal CT scans obtained in 23 patients during a 13-year period. Forty desmoid tumors were intraabdominal, including 30 lesions associated with Gardner's syndrome in 13 patients and 10 desmoids of the idiopathic form in 10 patients. These tumors were studied to define location; whether they were single or multiple; and whether they had any specific CT characteristics regarding margins, attenuation numbers, or contrast enhancement. RESULTS. Desmoid tumors associated with Gardner's syndrome were more likely to be multiple (38%, five of 13 patients) and to involve the mesentery (60%, 18 of 30 tumors) and the abdominal wall (40%, 12 of 30 tumors), whereas isolated desmoid tumors were singular (all 10 patients) and were located in the retroperitoneum (six cases), pelvis (three), and anterior wall (one). Desmoids related to Gardner's syndrome also tended to be smaller (mean diameter, 4.8 cm) than idiopathic desmoids (mean diameter, 13.8 cm). No differentiating CT characteristics regarding margins, attenuation numbers, or response to contrast material were ascertained. Ten new lesions (seven intraabdominal, three mesenteric) developed in three patients with Gardner's syndrome, whereas no new intraabdominal lesions developed in patients with idiopathic desmoids. Follow-up data on 16 surgically resected desmoids in nine patients (seven with Gardner's syndrome and two with isolated desmoids) revealed seven local recurrences (two in the two patients with isolated desmoids and five in two patients with Gardner's syndrome). CONCLUSION. No CT characteristics, such as attenuation values, margins, and response to the contrast material, were found that would enable differentiation between isolated intraabdominal desmoids and those associated with Gardner's disease. Desmoid tumors associated with Gardner's syndrome tend to occur in the mesentery and abdominal wall, whereas isolated desmoids involve the retroperitoneum and pelvis. When studying CT scans obtained over time, new lesions were noted to develop in a few of the patients with Gardner's syndrome (three of 13), whereas no new lesions were found in patients with isolated desmoids.