From the Guidelines
The signet ring sign in the lung is a diagnostic feature of bronchiectasis, characterized by a dilated bronchus appearing larger than the accompanying artery on high-resolution CT (HRCT) scans, as noted in the study by 1. This sign is crucial for diagnosing bronchiectasis, a condition marked by permanent dilation and damage to the airways. The key feature of bronchiectasis on HRCT scans is the enlarged internal bronchial diameter, where the bronchi appear larger than the accompanying artery, referred to as the signet ring sign 1. Other HRCT scan findings in bronchiectasis include the failure of the larger airways to taper while progressing to the lung periphery, air-fluid levels in dilated airways, and the identification of airways in the extreme lung periphery 1. Indirect HRCT scan signs of bronchiectasis include bronchial wall thickening, mucoid impaction, and focal air-trapping 1. The presence of the signet ring sign suggests the need for further evaluation to determine the underlying cause of bronchiectasis, which can include conditions such as cystic fibrosis, recurrent infections, immunodeficiency disorders, or post-inflammatory damage. Treatment may involve antibiotics for infections, airway clearance techniques, bronchodilators, or in severe cases, surgical intervention. The identification of multiple signet ring signs throughout the lungs indicates more extensive bronchiectatic disease and potentially worse prognosis, necessitating comprehensive pulmonary management. In clinical practice, the signet ring sign is a valuable diagnostic tool for identifying bronchiectasis and guiding appropriate treatment, as emphasized by the study 1.
From the Research
Signet Ring Sign in Lung
- The signet ring sign in lung refers to a specific type of adenocarcinoma characterized by the presence of signet ring cells, which are mucin-producing cells with a distinctive signet ring appearance under the microscope 2, 3, 4.
- Primary signet ring cell adenocarcinoma of the lung is a rare subtype of lung cancer, with only a few cases reported in the literature 2, 4, 5.
- The clinicopathological features of primary signet ring cell adenocarcinoma of the lung include a high proportion of poorly differentiated tumor and stage IV disease, with a significant number of patients being never smokers 5.
- The diagnosis of primary signet ring cell adenocarcinoma of the lung can be challenging, as the signet ring cells can be mistaken for metastatic adenocarcinoma from an occult primary 2, 3.
- Immunohistochemical stains, such as TTF-1 and cytokeratin 7, can be helpful in diagnosing primary signet ring cell adenocarcinoma of the lung 2, 3.
Imaging Features
- There is limited information available on the specific imaging features of signet ring cell adenocarcinoma of the lung, as the existing studies focus on the clinicopathological and immunohistochemical characteristics of the disease 2, 3, 4, 5.
- However, one study mentions that high-resolution CT scans can be used to assess the pattern and distribution of abnormalities in patients with bronchiectasis, which can be a related condition 6.
Prognosis and Treatment
- Primary signet ring cell adenocarcinoma of the lung is associated with a poor prognosis, with a decreased overall survival compared to adenocarcinoma of the lung 5.
- The treatment of primary signet ring cell adenocarcinoma of the lung is not well established, but it is likely to involve a combination of surgery, chemotherapy, and targeted therapy, depending on the specific characteristics of the tumor 2, 3, 5.