Desmoid tumors are rare neoplasms arising at the site of any fascia. Although histologically benign, they can cause local infiltration and they also carry a risk of recurrence. We describe the case of an 11-year-old girl who presented with a desmoid tumor at the site of an old trauma, and we briefly review the literature of this lesion.
Desmoid tumors (DTs), also referred as aggressive fibromatosis (AF), are rare neoplasms arising from fascial/muscloaponeurotic stromal structures or soft tissue [1,2]. Although histologically benign and with no known potential for metastasis, DTs may cause local infiltration and compression of the surrounding tissues [
An 11-year-old girl presented to the pediatric Emergency Department, complaining of lower right quadrant abdominal pain. The patient’s history was remarkable only for an uncomplicated open appendectomy performed 20 months earlier, with no other history of disease or surgery. She had no relevant family history of FAP or similar conditions. Physical examination revealed a firm, painful mass at the site of the scar of the previous appendectomy. Blood work-up results were normal. A Doppler ultrasound (US) examination revealed a dense fusiform mass, located 1 - 2 cm below the old surgical scar in the right lower abdominal wall, measuring 3.31 × 1.62 × 3.34 cm with poor internal vascularization. A T1-weighted magnetic resonance imaging study (MRI) (Figures 1(a) and (b)) revealed an enhancing lesion located on the transversalis fascia and aponeurosis of the abdominal muscles on the right. At surgery, the tumor was found to have infiltrated the surrounding muscles; the rectus sheath and the peritoneum were intact. The tumor was radically excised along with part of the internal and external oblique muscles and transversalis fascia. Macroscopic examination identified a firm, oval-shaped, yellow-brown tumor with irregular margins (
Histologic investigation of the specimen revealed a fibroblastic neoplasm consisting of spindle-shaped cells of uniform appearance, set in a collagenous stroma (
The postoperative course was uneventful, and the patient was discharged in good health.
First described in 1832, this lesion acquired its name in 1838 [
rives from the word desmos that means band or tendon [
The incidence of sporadic cases of DTs observed in the general population is estimated to be 2 to 4 new cases per million people per year, and represents about 0.03% of all neoplasms and 3% of all soft tumors [
DTs account for less than 1% of all tumors [
Though the exact etiology of DTs remains obscure, an association has been well described with dysregulation of the beta-catenin pathway caused by mutation of the adenomatous polyposis coli (APC) suppressor tumor gene which regulates the cellular levels of beta-catenin [
Surgical trauma represents one of the factors that possibly contribute to the pathogenesis of sporadic abdominal wall DTs. The tumor usually arises from the musculoaponeurotic structures, especially the rectus and internal oblique muscles and their fasciae [
The reported incidence of sporadic DTs after surgery among adults [2,7,19] varies between 14% and 33%. Data for the pediatric population is limited. In a series of 63 children with DT in various sites, Faulkner et al. [
Warren [
Although CT and especially MRI are useful in defining the anatomic margins of the tumor and its resectability, they are unable to distinguish DTs from other masses [
There is no optimal treatment for DTs as yet, owing to the lack of prospective randomized studies; large pediatric series are retrospective [5,20,22,31,32]. Where feasible, the current treatment of choice for DTs is complete surgical excision with negative surgical margins [522,32]; the risk of recurrence reaches 16% as compared to 67% with positive surgical margins [5,20,33-36]. However, in the case of an incomplete resection and potential risk of morbidity due to a second operation, adjuvant treatment with chemotherapy and/or noncytotoxic drugs or radiotherapy is recommended [5,37]. Notwithstanding, the role of chemotherapy is questionable. Buitendijk et al. [
Despite the relative rarity of DTs, the presence of a mass in an old laparotomy scar should raise suspicion of the lesion. An appropriate pre-operative work-up is essential, and surgery with negative margins is the treatment of choice. A close follow-up is recommended.