Extra-abdominal desmoid tumors, or aggressive fibromatoses, represent (along with, perhaps, giant cell tumor of bone) one of the most perplexing and vexing benign disease processes that musculoskeletal oncologists and allied physicians face. Despite its technically non-malignant nature, the disease course and the local or systemic treatments can be morbid and anything but ‘‘benign.’’ Indeed, recurrence rates following attempted local control surgery are often strikingly high, and the best rates (;20%) routinely exceed the published and acceptable local recurrence rates for soft-tissue sarcomas. Some of these findings doubtless stem from the reluctance of surgeons (and patients) to sacrifice critical or functional adjacent structures and thus achieve truly wide operative resections for management of a benign condition. The ability to achieve successful wide excision may be further compromised by our inability to accurately define the gross margins of the disease. Radiation therapy or systemic chemotherapy, while demonstrating modest measurable efficacy, is similarly underwhelming in terms of both durable local control and treatment side effects—and the practice of offering a ‘‘malignant’’ treatment for a benign diagnosis remains hotly debated. Given the absence of particularly effective treatment options, Briand et al. evaluated the efficacy of managing extra-abdominal desmoid tumors with a conservative, wait-and-see approach of medical symptom mitigation and observation via serial clinical and magnetic resonance imaging (MRI) examinations. The two-center, retrospective study included fifty-five patients with thirty-one primary and twenty-four recurrent extra-abdominal desmoid tumors managed over a decade. During this same period, twentynine additional patients were managed with primary surgery, with the majority of these operations performed prior to 2005, when at both study centers the wait-and-see approach was extended from being used for only recurrent extra-abdominal desmoid tumors to being employed for primary tumors as well. The primary end point of the study was defined as dropping out from the wait-andsee approach—that is, undergoing surgical resection—because of local disease progression, intractable worsening of disease-related symptoms, or a change in the patient’s wishes manifesting as a preference to undergo surgical resection. The authors found that the cumulative probability of dropping out from the wait-and-see approach was 5.7% at one year and 9.6% at two, five, and ten years; the results noted for the recurrent extra-abdominal desmoid tumors were slightly better than those for the primary extra-abdominal desmoid tumors. Furthermore, 50% of the patients demonstrated a nonprogressive tumor (defined, according to the Response Evaluation Criteria in Solid Tumors [RECIST] guidelines, as a <20% increase in tumor diameter on consecutive six-month MRI scans) at one year, which increased to 80%, 100%, and 100% at two, five, and ten years, respectively. Finally, spontaneous tumor resolution within two years occurred in five patients, and only one patient (2%) demonstrated tumor progression three years following presentation. Limitations of the study include the obvious—namely, the retrospective nature of the review and the modest total number of patients with primary or recurrent extra-abdominal desmoid tumors included. Given the rarity of the disease process, limitations such as these are unavoidable in the absence of a multi-institutional prospective observational or randomized trial of primary surgery versus conservative management. As the authors openly state, wait-and-see management evolved over time during the study period, resulting in a discrepancy of greater than three years between the median follow-up durations of the primary and recurrent-tumor cohorts, and relatively more patients being excluded and selected for primary surgical management earlier in the study. Symptom management and referrals to pain specialists both became more proactive and aggressive during the study period, which has important implications for patient dropout, compliance, and satisfaction and extrapolation of these findings to other institutions. The inclusion of two institutions and multiple treating physicians was a relative study strength but also highlights the subjective nature of the decisions to exclude patients from the wait-and-see policy either outright or by facilitating ‘‘dropout’’ during the observation period. Prior studies of conservative management of extra-abdominal desmoid tumors, as outlined in Table E-1 in the article by Briand et al., have demonstrated a crude composite success rate of approximately 86%; however, in the largest of these reports, by Fiore et al., conservative management was ultimately successful in <70% of patients. This suggests that, via either proactive e69(1)