The Clinical Features of Multicentric Extra-abdominal Desmoid Tumors
Desmoids are rare tumors which are considered locally invasive but non-metastasizing, with a reported incidence of 2-4 per million population and account for 0.03% of all neoplasms (1-4). The World Health Organization has characterized desmoids as intermediate, locally aggressive tumors (5).
Histologically, desmoids are characterized by the proliferation of uniform spindle cells resembling myofibroblasts, in a background of abundant collagenous stroma and vascular network (6). On immunohistochemistry, desmoids stain positively for nuclear beta-catenin, vimentin, cyclo-oxygenase-2, tyrosine kinase, platelet-derived growth factor receptor B, androgen receptor, and estrogen receptor beta. Desmoids stain negatively for desmin, S-100, H-caldesmon, CD34, and c-KIT (7). Nuclear beta-catenin positivity supports the diagnosis of desmoid.
They are classified according to their location: extra-abdominal, abdominal wall or intra-abdominal. Extra-abdominal desmoid tumors often occur in the neck, chest wall, shoulder, back, arm, buttock, thigh and leg. Of these tumors, multicentric extra-abdominal desmoids are rather rare and seem to have other clinical features. Previous reports showed that multicentric extra-abdominal desmoids arose in the same extremity (8-11). The aim of our study was to investigate clinical features of extra-abdominal desmoid tumors, especially their multicentric occurrence.
Patients and Methods
A total of 135 patients diagnosed with extra-abdominal desmoids were enrolled in this study from January 2005 to December 2019 at the Cancer Institute Hospital of The Japanese Foundation for Cancer Research. Clinical and pathological data were collected by reviewing medical records at our Institution, with the last follow-up conducted in December 2019. All patients consented to use of their medical records in articles or meetings and all patient data were strictly anonymized. The inclusion criterion was a confirmed pathological diagnosis by a pathologist at our Institution through histological characteristics of the biopsy specimen. Immunohistochemistry for nuclear beta-catenin positivity was applied in all cases retrospectively to confirm the pathological diagnosis. Patients with no beta-catenin translocation to the nucleus or with hereditary disease such as familial adenomatous polyposis or Gardner syndrome were excluded. The tumors were classified by their location as extra-abdominal, of the abdominal wall, or intra-abdominal. The following demographic data and treatment factors were examined retrospectively for multicentric occurrence: Age at diagnosis (<60 or ≥60 years), gender, pain, restriction of range of motion (ROM), tumor site, tumor size (<5 or ≥5 cm), surgical margin, multicentric occurrence, local recurrence and tumoral regression. Tumoral regression was defined as the disappearance of enhancement on gadolinium-enhanced magnetic resonance imaging (MRI). The surgical margin was pathologically confirmed through surgical specimens by a pathologist. Multicentric occurrence was defined as tumoral extension to several muscles by gadolinium-enhanced MRI at the patient’s first visit (orange arrows in
Extra-abdominal desmoid tumors often occur in the neck, shoulder, axilla, chest wall, arm, back, buttock, thigh and leg. Of these tumors, multicentric extra-abdominal desmoids are rather rare and seem to have other clinical features. In this study, we investigated clinical features of extra-abdominal desmoid tumors.
Multicentric extra-abdominal desmoids generally arise in the same extremity (8-11). Previous studies referred to multicentric extra-abdominal desmoids but the definition of multicentric extra-abdominal desmoids was not standardized (11,12).
In this study, we defined multicentric occurrence as tumoral extension to several muscles by gadolinium-enhanced MRI at first presentation. Whether tumoral extension of muscles are adjacent to each other was not considered. Hereditary disease like familial adenomatous polyposis or Gardner syndrome were excluded.
Multicentric extra-abdominal desmoids were associated with a high local recurrence rate (
Surgery should be performed in patients who have severe pain or joint contracture. Given the high local-recurrence rate after surgery and the fact that surgical margin status had no correlation with local recurrence, a 'Wait and see' policy is an appropriate first-line management, especially for those with multicentric extra-abdominal desmoids.
Conflicts of Interest
Yusuke Minami designed the study, and wrote the initial draft of the article. Yusuke Minami also contributed to analysis and interpretation of data, and assisted in the preparation of the article. All other Authors have contributed to data collection and interpretation, and critically reviewed the article. All Authors approved the final version of the article, and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
The Authors thank members of the Department of Orthopedic Oncology at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research for helpful discussions.