Pulmonary artery pseudoaneurysm arising from primary lung neoplasm: A proposed mechanism.

Pulmonary artery pseudoaneurysms (PAPs) are rare and life-threatening occurrences. We present a 57-year-old male patient with squamous cell lung cancer, who presented with hemoptysis. Bronchoscopy did not reveal ongoing bleeding. Imaging showed a left lower lobe tumor, a cavitary lesion communicating with the bronchus, and a pulmonary artery pseudoaneurysm. Successful embolization of the originating segmental branch of the pulmonary artery was performed. The pathogenesis of PAPs associated with primary lung malignancies remains poorly understood. We propose a four-step mechanism involving primary tumor expansion, central cavitary necrosis, direct arterial invasion, inflammatory response, vessel wall damage, pseudoaneurysm formation, and subsequent filling of the former cavitary lesion. This case emphasizes the importance of considering PAPs in primary lung malignancies, particularly in male patients with squamous cell pathology. Understanding the proposed pathogenic mechanism could lead to early detection, prompt intervention, and improved outcomes.

Ileocolonic intussusception presenting as chronic diarrhea in an elderly woman.

Video 1Colonoscopy findings of cecal mass as a lead point causing intussusception.

Evidence of an oncogenic gammaherpesvirus in domestic dogs.

In humans, chronic infection with the gammaherpesvirus Epstein-Barr virus is usually asymptomatic; however some infected individuals develop hematological and epithelial malignancies. The exact role of EBV in lymphomagenesis is poorly understood partly because of the lack of clinically relevant animal models. Here we report the detection of serological responses against EBV capsid antigens in healthy dogs and dogs with spontaneous lymphoma and that dogs with the highest antibody titers have B cell lymphoma. Moreover, we demonstrate the presence of EBV-like viral DNA and RNA sequences and Latent Membrane Protein-1 in malignant lymph nodes of dogs with lymphoma. Finally, electron microscopy of canine malignant B cells revealed the presence of classic herpesvirus particles. These findings suggest that dogs can be naturally infected with an EBV-like gammaherpesvirus that may contribute to lymphomagenesis and that dogs might represent a spontaneous model to investigate environmental and genetic factors that influence gammaherpesvirus-associated lymphomagenesis in humans.