Leiomyosarcoma of the small bowel presenting as an acute small bowel obstruction.

Leiomyosarcoma is a subtype of soft-tissue sarcoma, which is a rare soft-tissue malignancy comprising < 1% of adult cancers. There are a variety of etiologies of small bowel obstruction. Infrequently, small bowel malignancies can first present as small bowel obstruction. In exceedingly rare cases, leiomyosarcomas can be the offending malignancy. A 53-year-old male presented to the emergency department with several weeks of persistent right abdominal pain, nausea, and vomiting. Computed tomography scan revealed a central necrotic mass within the right lower quadrant originating from the small bowel. The patient underwent exploratory laparotomy to relieve the obstruction and a mass was identified originating from the terminal ileum that adhered to surrounding structures. Pathological analysis determined the mass to be small bowel leiomyosarcoma. Leiomyosarcoma is definitively diagnosed after primary resection with histopathology and immunohistochemistry. As opposed to other small bowel neoplasms, surgical resection with negative margins is the only potentially curative option.

Dissociating motor impairment from five-choice serial reaction time task performance in a mouse model of Angelman syndrome.

Angelman syndrome (AS) is a single-gene neurodevelopmental disorder associated with cognitive and motor impairment, seizures, lack of speech, and disrupted sleep. AS is caused by loss-of-function mutations in the UBE3A gene, and approaches to reinstate functional UBE3A are currently in clinical trials in children. Behavioral testing in a mouse model of AS (Ube3a m-/p+ ) represents an important tool to assess the effectiveness of current and future treatments preclinically. Existing behavioral tests effectively model motor impairments, but not cognitive impairments, in Ube3a m-/p+ mice. Here we tested the hypothesis that the 5-choice serial reaction time task (5CSRTT) can be used to assess cognitive behaviors in Ube3a m-/p+ mice. Ube3a m-/p+ mice had more omissions during 5CSRTT training than wild-type littermate controls, but also showed impaired motor function including open field hypoactivity and delays in eating pellet rewards. Motor impairments thus presented an important confound for interpreting this group difference in omissions. We report that despite hypoactivity during habituation, Ube3a m-/p+ mice had normal response latencies to retrieve rewards during 5CSRTT training. We also accounted for delays in eating pellet rewards by assessing omissions solely on trials where eating delays would not impact results. Thus, the increase in omissions in Ube3a m-/p+ mice is likely not caused by concurrent motor impairments. This work underscores the importance of considering how known motor impairments in Ube3a m-/p+ mice may affect behavioral performance in other domains. Our results also provide guidance on how to design a 5CSRTT protocol that is best suited for future studies in Ube3a mutants.