Desmoid-Type Fibromatosis in Children. Clinical Features, Treatment Response, and Long-Term Follow-up

Sixteen patients (18 desmoid tumors) were retrospectively evaluated. Initial surgery was performed in 13/18 tumors, with complete resection in 6 (one with free margin and five with microscopic residual disease); 10/13 had local relapse. Eleven patients with 13 tumors underwent treatment with methotrexate-vinblastine. The response rate to chemotherapy was 54%, and up to 81% if stable disease cases were included. Only 2 had grade 4 toxicity. Twelve of 15 patients had sequelae. In 8 cases sequelae were directly related to the surgical intervention and 3 of them were severe. The 5-year progression-free survival and overall survival were 30% and 93.3%, respectively. Low dose chemotherapy achieved stable disease and even remission of the lesions with low toxicity. The high rate of sequelae is probably related to the initial surgery performed in the majority of patients and may be avoided by the use of neoadjuvant low dose chemotherapy.

Desmoid-type fibromatosis typically manifests as a deeply seated but poorly circumscribed soft-tissue mass. Herein, we present the case of a 78-year-old man who developed a gradually progressive painless swelling over the right side of the neck over a period of 6 months. The patient was planned for a magnetic resonance imaging scan which showed ill-defined lobulated mass in the right trapezius of size 4 × 7 × 5.4 cm, which was heterogeneous in T2, isointense in T1, multiple ovoid calcifications, and was suspected with cysticercosis or fibroma. Open biopsy was done a week later which was suggestive of fibromatosis. The patient underwent definitive resection of the tumor 1 week later and the tumor was found to be restricted to the muscular plane. Histology was consistent with fibromatosis, the specimen being positive for vimentin, beta-catenin, and smooth muscle actin. The patient was on serial follow-ups and the last follow-up, 3 year later did not show any signs of recurrence of the tumor.

Abdominal wall endometriosis (AWE) in young women, with previous gynecological abdominal surgery, is the first condition considered by many practitioners when a tumor in the region of the scar appears. AWE seems to be caused by an iatrogenic transfer of endometrial cells at the level of the scar. Despite the fact that the disease could be totally asymptomatic, there are certain risk factors that can be identified during the anamnesis, such as: heredity, menarche at the age of >14 years, menstrual cycle <27 days, delayed menopause, excessive alcohol and caffeine consumption. Suggestive signs include cyclic or continuous abdominal pain caused by a palpable abdominal wall mass with a maximum tenderness in the region of the surgical scar. The differential diagnosis is complex and rare entities like desmoid tumors (DTs) must be taken into consideration. Desmoid tumor, or the so-called aggressive fibromatosis (AF), is a rare fibroblastic proliferation. This tumor can develop in any muscular aponeurotic structure of the body and is considered benign but with a high recurrence rate. DTs can cause local infiltration, subsequently producing certain levels of deformity and potential obstruction of vital structures and organs. The differential diagnosis is challenging in this situations, the imagery exams are useful, especially in detecting the precise location of the tumor. The histological examination of the tumor can state the final and precise diagnosis.

The purpose of the present study was to delineate the clinicopathologic features and explore the prognostic factors of abdominal desmoid tumors (ADTs). From January 2000 to January 2019, patients with ADTs who underwent macroscopically complete resection at the China National Cancer Center were included in the study. The clinicopathologic characteristics and follow-up data were carefully collected and reviewed. Prognostic factors such as age at presentation, sex, tumor location, tumor size and tumor proximity to nerves or vasculature were analyzed, and recurrence-free survival was analyzed with these factors. A total of 113 patients with ADTs were assigned to the abdominal wall group (n = 66) or abdominal cavity group (n = 47) according to the tumor site. Abdominal wall DTs and intra-abdominal DTs demonstrated distinct clinicopathological features and prognoses. During a median 61-month follow-up period, twelve (10.2%) patients had local recurrence. According to the univariate and multivariate analyses, intra-abdominal tumors, large tumors, and positive margins were independent risk factors for poor prognosis. Compared with intra-abdominal DTs, abdominal wall DTs demonstrate different clinicopathological features and a better prognosis. Under the premise of ensuring negative margins during the rst surgical procedure, patients with abdominal wall DTs can obtain satisfactory prognoses through radical resection.

We present a clinical case of a female, 15 year old patient, with three months of abdominal pain, a giant intra-abdominal mass was diagnosed with histologic diagnosis of desmoid tumor. Several surgical procedures were performed, having a las a R1 resection (focally microscopic margins). In this case association with pregnancy, abdominal trauma, previous surgeries and genetic syndromes were discarded.

Desmoid-type fibromatosis following thoracotomy is rare and has been previously reported only in <20 cases; however, it might mimic chest wall recurrence of previous cancer and needs differential diagnosis. When the tumor location corresponded to the thoracotomy incision, we should consider desmoid-type fibromatosis as a differential diagnosis.