The sandwich sign of non-lymphomatous origin

Visual Illusions in Radiology: Untrue Perceptions in Medical Images and Their Implications for Diagnostic Accuracy

Errors in radiologic interpretation are largely the result of failures of perception. This remains true despite the increasing use of computer-aided detection and diagnosis. We surveyed the literature on visual illusions during the viewing of radiologic images. Misperception of anatomical structures is a potential cause of error that can lead to patient harm if disease is seen when none is present. However, visual illusions can also help enhance the ability of radiologists to detect and characterize abnormalities. Indeed, radiologists have learned to exploit certain perceptual biases in diagnostic findings and as training tools. We propose that further detailed study of radiologic illusions would help clarify the mechanisms underlying radiologic performance and provide additional heuristics to improve radiologist training and reduce medical error.

Intra-abdominal fat. Part III. Neoplasms lesions of the adipose tissue

This article focuses on various cancerous lesions that are found beyond organs in the intra-abdominal fat and can be visualized with ultrasonography. These lesions are divided into five groups. The first group includes primary benign tumors containing adipocytes, such as lipoma, lipoblastoma, hibernoma and other lesions with an adipose tissue component, such as myolipoma, angiomyolipoma, myelolipoma and teratoma. The second group comprises primary malignant adipocytecontaining tumors, including liposarcoma and immature teratoma. The third group contains primary benign tumors without an adipocyte component that are located in intra-abdominal fat. This is a numerous group of lesions represented by cystic and solid tumors. The fourth group encompasses primary malignant tumors without an adipocyte component that are located in intra-abdominal fat. These are rare lesions associated mainly with sarcomas: fibrosarcoma, malignant fibrous histiocytoma, hemangiopericytoma and leiomyosarcoma. An epithelioid tumor at this site is mesothelioma. The last but not least group includes secondary malignant tumors without an adipocyte component located in intra-abdominal fat. This is the most numerous group with prevailing carcinoma foci. For each of these groups, the authors present ultrasound features of individual lesions and discuss their differential diagnosis. In the vast majority of cases, the material for cytological and histological analysis can be obtained during ultrasound-guided procedures. This is the advantage of this imaging modality.

The pleural sandwich sign in two cases of primary pleural lymphoma

The sandwich sign is used to describe mesenteric lymphoma in which mesenteric vessels and fat are enveloped by enlarged mesenteric lymph nodes. We present two cases of primary pleural lymphoma demonstrating the "pleural sandwich sign". Contrast-enhanced computed tomography showed conglomerated parietal pleural and extrapleural masses encasing the intercostal arteries. Histopathological examinations confirmed low grade marginal zone B-cell lymphoma in an 80-year-old man and diffuse large B-cell lymphoma in a 68-year-old man. The pleural sandwich sign may suggest the diagnosis of primary pleural lymphoma.