Early morphological changes in cardiac mitochondria after subcutaneous administration of trastuzumab in rabbits: possible prevention with oral selenium supplementation.

Trastuzumab-mediated cardiotoxicity poses a significant challenge in the treatment of human epidermal growth factor receptor 2-positive breast cancer. To understand the underlying mechanisms, we conducted experiments to determine ultrastructural changes of rabbit cardiac tissue under different experimental conditions, including differing doses of trastuzumab and supplementation with oral sodium selenite, an antioxidant. Histopathology revealed lymphocyte and macrophage infiltration in myocardium of rabbits receiving four doses of trastuzumab. Transmission electron microscopy showed substantial changes with trastuzumab, including edema with separation of myofibril bundles and rupture of sarcomeres. Within mitochondria, edema resulted in disorganization of the cristae. Some mitochondria exhibited eccentric projections of their membranes with disruption of both inner and outer membranes. These changes were seen to a lesser extent in rabbits who received oral sodium selenite prior to trastuzumab. Selenium is integral to functioning of mitochondrial glutathione peroxidases, important antioxidants that also maintain membrane integrity. If mitochondria are disrupted as part of trastuzumab cardiac toxicity, selenium supplementation might be an important therapeutic or preventive consideration. Larger studies to explore this hypothesis are warranted.

Listeriosis in an immunocompetent patient after diagnostic colonoscopy.

We present an 80-year-old female with type II diabetes (well controlled) who presented to the emergency department with a hemoglobin of 6.5 mg/d consistent with iron deficiency anemia (IDA). As part of the workup for IDA, she had an esophagogastroduodenoscopy (EGD) and colonoscopy. EGD was unremarkable. Colonoscopy revealed a mass occupying about 50% of the circumference of her descending colon suspicious for malignancy, which was biopsied. Thirty-six hours later, she developed fevers; blood cultures grew Listeria monocytogenes. Workup to identify the source of bacteremia was negative for other sources of infection. Due to the temporal relationship, the development of bacteremia was attributed to the disturbance of the gastrointestinal tract possibly from recent biopsy of the colonic mass. She was treated with penicillin for a total of about 4 weeks with complete resolution of symptoms and clearance of bacteremia. She had a transverse colectomy 6 weeks later with surgical pathology of the lesion showing intramucosal adenocarcinoma. This case represents a rare complication of colonoscopy and is novel because our patient was not immunocompromised as previously reported in other cases.

Blastic plasmacytoid dendritic cell neoplasm.

Blastic plasmacytoid dendritic cell neoplasm is an aggressive neoplasm with a median survival of only a few months despite treatment. An exhaustive immunohistochemical workup is required to differentiate it from myeloid sarcoma and extranodal NK/T cell lymphoma. Treatment is with induction using a regimen utilized for leukemia. Allogeneic hematopoietic stem cell transplantation is recommended for those who achieve remission following induction.