Abdominal wall endometriosis versus desmoid tumor – a challenging differential diagnosis

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.

The lesions were growing along the musculoaponeurotic fascia, mostly invaded the muscles, and showed ill-defined margins, low T2 signal bands and areas, and facial tail sign. Diffusion images showed mostly high or high mixed with low signal; only 2 lesions showed a persistent low signal. Post-contrast and DWI detected synchronous lesions and extensions missed on T1 and T2 images. The most frequent MR features of deep fibromatosis are low T2 signal bands and areas, fascial tail sign, ill or partially defined margins, and predominant restricted diffusion pattern in addition to areas of “T2-blackout effect.” Post-contrast and DWI are more valuable in local staging of the tumor.

We reviewed the clinical data from 16 patients who were diagnosed with intra-abdominal aggressive fibromatosis and were admitted to Peking Union Medical College Hospital between March 1983 and September 2018. Among the 16 patients, 11 patients presented with a hard smooth abdominal mass with clear borders and a diameter of 4.3-25.0 cm. Six patients had a history of abdominal surgery and 3 patients had a history of familial adenomatous polyposis. Computed tomography imaging revealed a slightly dense mass with mild-to-moderate enhancement. Of all the 16 patients, 11 patients underwent surgical treatment and no recurrence occurred in 10 case after complete resection while recurrence occurred in 1 case after partial resection. Two patients underwent surveillance and 3 patients received cytotoxic drugs treatment, and no disease progression was observed via imaging during their follow-up.