Myxoid liposarcoma is a malignant adipogenic neoplasm characterized by prominent arborizing capillaries, occasional lipoblasts, and primitive-appearing spindle cells in a myxoid background. A recurrent translocation in myxoid liposarcoma results in an oncoprotein consisting of full-length DDIT3 (CHOP) fused to an N-terminal segment of either FUS (TLS) or, less often, EWSR1. Here, we explore the diagnostic significance of DDIT3 expression in myxoid liposarcoma using a mouse monoclonal antibody recognizing an epitope in the N-terminal region. Studying a total of 300 tumors, we find diffuse, moderate-to-strong nuclear-localized anti-DDIT3 immunoreactivity in all 46 cases of myxoid liposarcoma representing 36 unique tumors, including 6 cases with high-grade (round cell) morphology. DDIT3 immunohistochemistry also highlighted a distinctive vasculocentric growth pattern in 7 myxoid liposarcomas treated with neoadjuvant radiation. In contrast, the vast majority of other examined lipomatous and myxoid neoplasms exhibited no DDIT3 expression; limited, weak immunoreactivity in <10% of cells was infrequently observed in dedifferentiated liposarcoma (6/39, 15%), solitary fibrous tumor (3/12, 25%), pleomorphic liposarcoma (1/15, 7%), and high-grade myxofibrosarcoma (2/17, 12%). Although this minimal DDIT3 expression did not correlate with DDIT3 amplification or myxoid liposarcoma–like morphology in dedifferentiated liposarcoma, there was evidence among sarcomas (excluding myxoid liposarcoma) of a relationship between expression and exposure to neoadjuvant radiation or cytotoxic chemotherapy. The constellation of findings indicates that DDIT3 immunohistochemistry may have utility in the evaluation of myxoid and lipomatous neoplasms to support the diagnosis of myxoid liposarcoma.

Objective Integrins contribute to vascular morphogenesis through regulation of adhesion and assembly of the extracellular matrix. However the role of β1-integrin in the mature vascular wall is less clear. Approach and Results We sought to determine the function of β1-integrin in mature smooth muscle cells in vivo using a loss of function approach by crossing a tamoxifen-inducible sm22αCre line to a floxed β1-integrin transgenic line. Adult mice lacking smooth muscle β1-integrin survived only ten weeks post-induction. The deletion of β1-integrin resulted in profound loss of vasomotor control. Histological analysis revealed progressive fibrosis in arteries with associated apoptosis of smooth muscle cells that was not rescued by adventitial stem cells. Smooth muscle cell apoptosis was detected in arteries with dead cells replaced primarily by collagen. Despite the catastrophic effects on vascular smooth muscle, the deleted visceral smooth muscle remained viable with the exception of a short portion of the colon, indicating that vascular but not visceral smooth muscle is particularly sensitive to changes in β1-integrin. Conclusions This study reveals an essential function of β1-integrin in the maintenance of vasomotor control and highlights a critical role for β1-integrin in vascular, but not visceral, smooth muscle survival.

Objectives Determine the ability of three staging systems to stratify the risk of nodal metastases in cases of cutaneous squamous cell carcinoma (cSCC). Examine differential staging of tumors across the three systems and the resulting implications for clinical decision making. Study Design Retrospective chart review. Methods This study included 118 patients who underwent excision of primary cSCC of the head and neck as well as elective neck dissection for the same tumor between 2006 and 2017. Tumors were staged using the 2010 7th edition American Joint Committee on Cancer (AJCC 7) staging system, the 2016 8th edition AJCC staging system (AJCC 8), and the Brigham and Women's Hospital (BWH) alternative tumor staging system published in 2013. Results There were 28 patients (23.7%) with positive nodal metastases at the time of tumor excision. Almost all tumors staged as tumor (T)2 using AJCC 7 were upstaged to T3 or T4 using the new AJCC 8, and these two groups accounted for the majority of the nodal metastases. Similarly, the BWH‐staged T3 group contained the highest number of tumors with nodal metastases. None of the three staging systems significantly stratified tumors in a manner that predicted the presence of nodal metastases. Conclusion Individuals with cSCC tumors staged T3 or higher in the AJCC 8 and BWH staging systems should undergo neck dissection, whereas those with lower staging should be discussed with the patient on a case‐by‐case basis. Level of Evidence: 4

The significance of post-transplant HLA DSA and chronic AMR in LT is an emerging field of study. Although OPV has previously been described as a histopathologic finding in DSA-positive adult LT recipients, it was not included in the recent Banff criteria for chronic AMR. Our aim was to describe the association between OPV and chronic AMR in pediatric LT recipients. A retrospective review of 67 liver biopsies performed between November 2014 and April 2016 in 45 pediatric LT recipients identified four patients with OPV. Clinical status, liver biochemistry, the presence of DSA, and available non-HLA antibody testing, as well as histopathologic features of chronic AMR, were assessed. All four patients with OPV had class II DSA and histopathologic features of chronic AMR based on the Banff criteria. Two patients were noted to have non-HLA antibodies. Three patients are undergoing treatment with IVIG but have persistent DSA. Two patients have graft failure and are awaiting retransplantation. In conclusion, OPV is a histopathologic finding associated with chronic AMR in pediatric LT recipients. Further studies are needed to elucidate whether OPV is reversible and/or amenable to medical therapy.