Histologic heterogeneity and intranodal shunt flow in lymph nodes from elderly subjects: a cadaveric study

Aging-Related Cellular, Structural and Functional Changes in the Lymph Nodes: A Significant Component of Immunosenescence? An Overview

Aging affects all tissues and organs. Aging of the immune system results in the severe disruption of its functions, leading to an increased susceptibility to infections, an increase in autoimmune disorders and cancer incidence, and a decreased response to vaccines. Lymph nodes are precisely organized structures of the peripheral lymphoid organs and are the key sites coordinating innate and long-term adaptive immune responses to external antigens and vaccines. They are also involved in immune tolerance. The aging of lymph nodes results in decreased cell transport to and within the nodes, a disturbance in the structure and organization of nodal zones, incorrect location of individual immune cell types and impaired intercellular interactions, as well as changes in the production of adequate amounts of chemokines and cytokines necessary for immune cell proliferation, survival and function, impaired naïve T- and B-cell homeostasis, and a diminished long-term humoral response. Understanding the causes of these stromal and lymphoid microenvironment changes in the lymph nodes that cause the aging-related dysfunction of the immune system can help to improve long-term immune responses and the effectiveness of vaccines in the elderly.

[Thoracic lymphatic system-principles, characteristics and advice for the practice]

The lymphatic system of the lungs is complex. To maintain an effective gas exchange there is a need for a dense lymphatic network. The alveolae have no lymphatic vessels. There is no segment-specific lymph drainage. For both lungs there are fixed bronchopulmonary lymph nodes but the number and size of the lymph nodes are variable. There are seven mediastinal lymph node chains that vary in extent, each of which acts as an independent functional unit. The accurate assessment of the nodal status needs a simple reproducible nodal map. The division into compartments or zones makes this easier. Mediastinal lymph node metastases without involvement of bronchopulmonary lymph nodes are possible. The development mechanism of this skip metastasizing is multifactorial.

[Rationale of thoracic lymph node dissection in pulmonary metastasectomy]

The goal of metastasectomy is a R0 resection. Depending of the tumor entity the prevalence of lymph node metastases in pulmonary metastasectomy can be up to 45%; however, systematic lymph node dissection is not yet established as a fixed component of metastasectomy. Although there is a high prevalence of lymph node metastases and the increase in the prevalence with a higher number of lung metastases, it remains unclear if a systematic lymph node dissection should be part of pulmonary metastasectomy. For this reason, the goal of this review was to evaluate the rationale of systematic lymph node dissection in pulmonary metastasectomy based on the currently available literature. Furthermore, it was investigated whether patients with additional thoracic lymph node metastases should be excluded per se from pulmonary metastasectomy, even though positive lymph node metastases might be associated with a lower but nevertheless good long-term survival after resection.

Clinical implication of microscopic anthracotic pigment in mediastinal staging of non-small cell lung cancer by endobronchial ultrasound-guided transbronchial needle aspiration

Microscopic anthracotic pigment (MAP) is frequently observed in endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) specimen in non-small cell lung cancer, but its clinical interpretation is not well-known. The aim of this study was to evaluate the clinical implication of MAP in mediastinal staging of non-small cell lung cancer. From May 2010 to July 2011, consecutive potentially operable non-small cell lung cancer patients who underwent EBUS-TBNA for mediastinal staging were recruited. Of the total 133 patients, 102 (76.7%) were male patients. Median age was 68 yr. Total 279 mediastinal lymph nodes were sampled by EBUS-TBNA; station 4R (100, 35.8%) and station 7 (86, 30.8%) were the most common sites. Malignant lymph nodes were 100 (35.8%). MAP was observed in 61 (21.7%) lymph nodes, and among them only 3 were malignant lymph nodes (P < 0.001). The lymph nodes with MAP were smaller (9.0 vs 10.8 mm, P = 0.001) and showed low standard uptake values on FDG-PET (4.4 vs 4.7, P = 0.256). In multivariate analysis, MAP was negatively associated with malignant lymph node (adjusted OR, 0.12; 95% CI, 0.03-0.42; P < 0.001). In potentially operable non-small cell lung cancer patients, MAP in endobronchial ultrasound-guided transbronchial needle aspiration specimens is strongly associated with benign mediastinal and hilar lymph nodes.

Morphological characteristics of lateral pelvic lymph nodes in rectal carcinoma

AIM

Macroscopic and imaging indicators for lymph node metastasis have been documented not in lateral pelvic lymph nodes but in mesorectal lymph nodes in patients with rectal carcinoma. We conducted this study to uncover morphological characteristics of lateral pelvic lymph nodes in patients with rectal carcinoma.

MATERIALS AND METHODS

Fifty-eight patients with locally advanced rectal carcinoma who had total mesorectal excision and lateral pelvic lymph node dissection were studied. Total number of lateral pelvic lymph nodes evaluated was 462, with 538 mesorectal lymph nodes being used for comparison. Factors of lymph nodes evaluated were size (long- and short-axes diameters), shape (ovoid and irregular), and heterogeneity of internal structure. Receiver operating characteristic (ROC) curve analysis was used to compare the diagnostic accuracy of each factor.

RESULTS

Lateral pelvic lymph node at non-metastatic status appeared to be longer (4.5 vs 3.5 mm) and thinner (2.2 vs 2.6 mm) than mesorectal lymph nodes. ROC curve analysis, for discriminating non-metastatic and metastatic lateral pelvic lymph nodes, revealed that a short-axis diameter appeared to be the most prominent factor with highest area under curve (0.907) and was more reliable than either long-axis diameter (0.811) or shape (0.527) other than internal structure (1.00). A short-axis diameter was an independent risk factor for metastasis by multivariate analysis with an odds ratio of 1.29 (p < 0.0001, 95% confident interval, 1.22-1.36). The most reliable cut-off value was 4 mm with 96% of sensitivity, 68% of specificity, and 82% of overall accuracy.

CONCLUSION

Lateral pelvic lymph nodes tended to be longer and thinner than mesorectal lymph nodes at non-metastatic status. A short-axis diameter of 4 mm or larger was the prominent indicator of metastasis in lateral pelvic lymph nodes.

Anatomy of right recurrent nerve node: why does early metastasis of esophageal cancer occur in it?

Early, distant and/or skip metastasis of squamous-cell thoracic esophageal cancer frequently occurs in the right recurrent nerve node (recR). However, the specific lymphatic route without a nodal relay, such as the submucosal ascending route, was not known for the recR afferent. Using 20 donated cadavers, macroscopic, and histological observations were performed on the recR and its surrounding lymphatics, especially afferent routes from the esophagus to the recR. Most afferent vessels of the recR originated from the right paratracheal node. However, the recR often (12/20) received a major submucosal lymphatic drainage route ascending along the thoracic esophagus. The submucosal vessel came out of the esophagus and ran in a longitudinal connective tissue mass along the right tracheo-esophageal groove. A direct drainage route was often (13/20) seen from the recR to the venous system. Moreover, because of the specific histology, collaterals seemed to be present around the recR. In the regional nodes of the intrathoracic esophagus, the recR histology was characterized by the high proportion of lymphocyte accumulating areas or the cortex. From the midthoracic level, metastatic cancer cells seemed to reach the recR via esophageal submucosal vessels in the early stage. Large lymphocyte accumulating areas of the recR suggested higher filtration capacity than other distal nodes. However, the collateral of the recR and its direct drainage to the venous system suggested that the recR involvement often corresponds to a systemic disease.