Regional Lymphatic System Research Articles

Symposium Highlight: PULMONARY LYMPHATICS HISTORY, ANATOMY, AND PATHOPHYSIOLOGY: EMERGING KNOWLEDGE AND A LOOK TO THE FUTURE

Central lymphatic disorders of the lung have not received intense investigation. Lymphatic system physiology is presented in the context of historical developments and basic lung lymphatic anatomy is reviewed followed by emerging characteristics of primary and secondary pathophysiological disturbances of lymphatic involvement in a number of pulmonary diseases including Gorham-Stout disease, pulmonary edema and infections and inflammatory conditions including lymphangioleiomyomatosis (LAM). The future includes potential molecular targeting of lymphangiogenesis or lymphatic vessels for interventional occlusion. This article is an amalgamation of presentations at the 2023 ISL International Congress of Lymphology, Genoa, Italy in a special symposium on central and regional lymphatic system in health and disease and as part of a Special Symposium on the Lymphatic system of the Heart and Lung in Health and Disease at the 26th International Congress of Lymphology meeting held in Barcelona, Spain, September 2017, which has been updated to 2024.

Symposium Highlight: PHYSIOLOGY AND FUNCTIONAL PATHOLOGY OF THE LYMPHATIC SYSTEM WITH IMPLICATIONS FOR THE FONTAN PATIENT

Contractile function of the collecting lymphatic vessels depend on smooth muscle cells, one-way valves, surrounding tissues, and regulation by the autonomic nervous system. The potentially deleterious effects of the Fontan procedure and elevated central venous pressure on lymphatic function leading to life-threatening complications are described. Presented at the 2023 ISL International Congress of Lymphology, Genoa, Italy in a special symposium on central and regional lymphatic system in health and disease.

Symposium Highlight: IMAGING AND INTERVENTIONAL MANAGEMENT OF LYMPHATIC DISORDERS

Lymphatic flow disorders are reviewed, and a classification based on magnetic resonance lymphography findings outlined. Examples of successful interventional management based on this classification are provided. Presented at the 2023 ISL International Congress of Lymphology, Genoa, Italy in a special symposium on central and regional lymphatic system in health and disease.

Symposium Highlight: LYMPHATIC IMAGING AND INTERVENTION IN CENTRAL LYMPHATIC DISORDERS

Advances in lymphatic imaging for both diagnosis and intervention are reviewed, and specific examples given for protein-losing enteropathy, multi compartment lymphatic failure, congestive heart failure. Presented at the 2023 ISL International Congress of Lymphology, Genoa, Italy in a special symposium on central and regional lymphatic system in health and disease.

Assessment of the prognostic significance of clinical and morphological factors on the survival of patients with locally advanced gastric cancer after radical surgical treatment: The experience of the Russian Center.

e16062 Background: Various staging systems are used to form a prognosis and determine an effective treatment strategy in patients with locally advanced gastric cancer (GC). Among these, the most widely used is the TNM UICC/AJCC staging system. However, even within the same stage, GC can vary significantly in terms of prognosis after surgery. The aim of our study was to assess the influence of clinical and pathomorphological biomarkers on the survival rate of patients with locally advanced GC after radical surgical treatment. Methods: For retrospective analysis, 124 patients were selected at the age from 29 to 86 years (mean age 65.69±10.09; 95% CI 63.90-67.49) with a diagnosis of stage I-III of GC who received only surgical treatment from 2015 to 2018. In 32 (26.1%) patients, the primary tumor was localized in the region of the cardioesophageal junction, in 61 (48.9%) - in the region of the stomach body, in 31 (25.0%) - in the pylorus. All patients underwent radical surgical treatment with subsequent staging of the disease according to the TNM system (6th edition), additional assessment of the lesion of the greater/lesser omentum. In 18 (14.5%) patients, stage IA was registered, in 10 (8.1%) - IB, in 23 (18.5%) - IIA, in 15 (12.1%) - IIB, 27 (21.8%) - IIIA, 26 (21.0%) - IIIB and 5 (4.0%) - IIIC. Results: We had a significant predictive value of the degree of metastatic lesions of the lesser and greater omentum (p <0.0001). The median OS in patients without omentum lesions at the time of assessment was not reached (follow-up period 42.0-54.0 months). The median OS in patients with only the greater omentum was 55.0 months (95% CI 6.5-55.0), which was 21.0 months higher than the median OS in patients with isolated lesions of the lesser omentum (24.0 months, 95% CI 19.0-57.0) and by 41.0 months exceeded the median OS of patients with combined lesions of the lesser and greater omentum (14.0 months, 95% CI 25.5-57). All factors that showed a significant effect on OS in the course of univariate analysis were included in the Cox proportional hazards model: the size of the primary tumor (T), the level of lesion of the regional lymphatic system (N), and the presence of lesions of the greater or lesser omentum. In general, the significance of the entire model was undeniable: p <0.0001. Significant prognostic influence was exerted by indicators characterizing the prevalence of the tumor process: T criterion (p=0.0090) and N criterion (p=0.0016). Conclusions: Despite the fact that, in multivariate analysis, the lesion of the greater and lesser omentum did not show a significant effect on OS in patients with locally advanced GC, this issue requires further study, since in the Cox model, the lesion of the lesser omentum, rather than the greater omentum, had a more favorable effect on the OS index. which allows you to increase RH by 12-60% (p=0.4046).

К вопросу о патогенезе затянувшегося течения экссудативного среднего отита

The article is devoted to the role of the regional lymphatic system of the middle ear, from the point of view of the pathogenesis of the prolonged presence of fluid in the air cavities of the temporal bone with a prolonged course of serous otitis media. The study was carried out in an experiment on a model of exudative otitis media in laboratory animals (20 sexually mature male Wistar rats). Studied the state of regional (superficial, facial, and deep) lymph nodes collecting lymph from the mastoid process, tympanic cavity; external auditory canal, auditory tube. Comparative morphological and morphometric studies of lymph nodes were carried out on the 12th day of experimental otitis media and were assessed according to 19 criteria: total area of the node section, area of the capsule, marginal sinus, cortex, paracortex, medullary sinuses, medullary cords, number and area of primary and secondary lymphoid nodules, area of germinal centers, specific areas of cortical and medullary substance, sinus system, cortical/medullary ratio (C/M index), T- and B-dependent areas. Disorders of lymph outflow in the middle ear area, different nature, and degree of response of regional lymph nodes of different groups to the exudative process were revealed. It is assumed that the restructuring of the structural organization of the nodes, reflecting the inhibition of their protective and drainage functions, can prolong the phenomena of lymphostasis in the area of the primary focus and lead to the protracted course of exudative otitis media in clinical practice.

Lymphedema microsurgery improved outcomes of pediatric primary extremity lymphedema.

Primary lymphedema is an anomaly of the regional lymphatic system with long symptom duration or severe lymphatic obstruction. Few microsurgical treatments for primary lymphedema have been reported. This aim of this study was to investigate the outcomes of microsurgical treatments in pediatric primary lymphedema patients. Between 2013 and 2017, pediatric primary lymphedema patients who underwent either lymphovenous anastomosis (LVA) or vascularized lymph node transfer (VLNT) were retrospectively reviewed. Cheng's Lymphedema Grading, Taiwan Lymphoscintigraphy Staging and indocyanine green lymphography were used to select the procedures. No compression garments were used postoperatively. Outcome measurements included circumferential difference, episodes of cellulitis, and Lymphedema-specific Quality of life questionnaire (LYMQoL). Nine patients with mean age of 9.2 years (range, 2-19 years) with 11 lower and two upper lymphedematous limbs underwent 11 VLNT and two LVA. All VLNT flaps survived. At a mean 38.4-months (range, 16-63 months) of follow-up, the mean circumferential difference in nine unilateral lymphedematous limbs was improved by 6.7 ± 9.9% (p = .066). Two patients with bilateral lower limb lymphedema had mean limb circumference improvements of 1.3 and 6.5 cm, respectively. In nine limbs with cellulitis preoperatively, episodes of cellulitis decreased by 2.67 times/year (p = .007). At a mean 22.3-months of follow-up (range, 13-24 months), the LYMQoL overall score in 6 patients older than 7 years was improved by 3.2 ± 1.1 points (p = .007). Lymphedema microsurgery significantly improved the episodes of cellulitis and quality of life without utilizing compression garments in pediatric primary lymphedema patients.

P2.18-08 The Necessity and Technique of the Upper Zone Lymph Node Dissection for Non-Small-Cell Carcinoma of the Left Upper Lobe

The removal of the whole regional lymphatic system together with primary tumor is one of the important rules in oncological surgery. According to the study of regional lymphatic drainage, we considered reasonable lymphadenectomy contributes the post-operative survival of the Left lung cancer patients with mediastinal lymph node metastasis. Due to anatomical limitations imposed by arch of aorta, it is difficult to perform complete dissection of upper zone mediastinal lymph nodes through the left thoracotomy in the left lung cancer. We had devised Systematic extended bilateral mediastinal dissection through a median sternotomy (ND3 operation) for patient with NSCLC of the left lung. This report aimed to introduce procedure of our operation and investigate the prognostic impact of Upper zone lymph node dissection for left upper lobe NSCLC. The our operative procedure is as follows. In the supine position, made a median sternotomy. We dissect the meidastinal nodes before pulmonary resection. The dissection is started on the highest area. Tape the right and left recurrent laryngeal nerve and dissect the highest paratracheal lymph nodes in the thoracic inlet. After making the pericardiotomy, the ascending aorta is retracted to the left. Remove the whole upper zone tissue lying in front of the trachea. And dissect the pre and paratracheal nodes, together with bilateral highest nodes. Then, dissect the subcarinal nodes. Tie off the blood vessels (arteries and veins) and airways leading to the affected lobe, and then remove the lobe. We retrospectively studied 213 patients [157 male and 61 female, mean ages 60.4 years (range, 29-75)], underwent ND3 operation due to NSCLC of the left upper lobe, from January 1990 till December 2017. The patients with NSCLC who are estimated to be able to conventional radical operation and aged 75 year-old or less becomes the adaptation of our operation. Overall 5-year survival rate in the 218 patients of left upper lung primary was 65.1%. Operative mortality in 218 patients was 2.8%. Lymph node metastasis to the mediastinum was confirmed in 70 (32.1%) patients (pN2 was 43, pN3α was 18, pN3γ was 9). According to pathological stages, five-year survival rate was 92.7% in stage IA ,80.1% in stage IB, 53.8% in stage IIA, 66.7% in stageIIB, 51.7% in stageIIIA, 38.4% in stageIIIB. And it was 52.1% in pN2 cases, and 55.0% in pN3α cases. Five-year disease free survival rate was was 85.6% in p-stage IA ,74.0% in p-stage IB,49.7% in p-stage IIA, 49.4% in p-stageIIB, 33.3% in p-stageIIIA, 19.4% in p-stageIIIB, 32.6% in pN2 cases, and 27.8% in pN3α cases. In this nonrandomized comrarision, the post-operative survival of patients with pN2 and pN3α NSCLC of the left upper lung primary would be remarkably improved by our Systematic Bilateral Mediastinal Dissection. And better local tumor control by our operation does not increase mortality. When faced with a patient with resectable mediastinal lymph node metastasis, we should consider Extended bilateral mediastinal lymph node dissection through a median sternotomy. To improve survival rate, it is important to perform curative operation with upper zone mediastinal dissection.

Imaging methods for the local lymphatic system of the axilla in early breast cancer in patients qualified for sentinel lymph node biopsy.

Breast cancer is the most common malignancy in women in well-developed countries. Despite a constant increase in its incidence, the percentage of patients diagnosed with the disease in the non-invasive stage is also rising. This allows more frequently for the use of breast-preserving surgical techniques, involving the breast and the regional lymphatic system.According to current guidelines of expert panels and research societies, the recommended method of identifying the sentinel lymph node is the use of an isotope marker with a dye (a combined isotope and dye method). Cooperation with a nuclear medicine unit is essential (performing a preoperative lymphoscintigraphic scan to identify the lymphatic drainage basin and sentinel lymph node). In the case of smaller centers treating breast cancer, it can be associated with a number of difficulties, including organizational ones, and also increasing general treatment costs.A possible solution to these problems is to use alternative techniques of visualizing the sentinel lymph node, which do not require a radiotracer. In this paper we discuss the currently available methods of mapping the lymphatic system of the axillary region in patients with early breast cancer. The review is limited to reporting on methods of proven (based on clinical research) high diagnostic value.

Magnetic graphene-based nanotheranostic agent for dual-modality mapping guided photothermal therapy in regional lymph nodal metastasis of pancreatic cancer

Although regional lymph nodes (RLN) dissection remains the only way to cure pancreatic cancer metastasis, it is unavoidably associated with sizable trauma, multiple complications, and low surgical resection rates. Thus, exploring a treatment approach for the ablation of drug-resistant pancreatic cancer is always of great concern. Moreover, reoperative and intraoperative mapping of RLN is also important during treatment, because only a few lymph nodes can be detected by the naked eye. In our study, graphene oxides modified with iron oxide nanoparticles (GO-IONP) as a nanotheranostic agent is firstly developed to diagnose and treat RLN metastasis of pancreatic cancer. The approach was designed based on clinical practice, the GO-IONP agent directly injected into the tumor was transported to RLN via lymphatic vessels. Compared to commercial carbon nanoparticles currently used in the clinic operation, the GO-IONP showed powerful ability of dual-modality mapping of regional lymphatic system by magnetic resonance imaging (MRI), as well as dark color of the agent providing valuable information that was instrumental for surgeon in making the preoperative plan before operation and intraoperatively distinguish RLN from surrounding tissue. Under the guidance of dual-modality mapping, we further demonstrated that metastatic lymph nodes including abdominal nodes could be effectively ablated by near-infrared (NIR) irradiation with an incision operation. The lower systematic toxicity of GO-IONP and satisfying safety of photothermal therapy (PTT) to neighbor tissues have also been clearly illustrated in our animal experiments. Using GO-IONP as a nanotheranostic agent presents an approach for mapping and photothermal ablation of RLN, the later may serve as an alternative to lymph node dissection by invasive surgery.

IL-10, IL-4, and STAT6 Promote an M2 Milieu Required for Termination of P0106-125-Induced Murine Experimental Autoimmune Neuritis

The role of the type 2 helper T cell (Th2)-polarizing cytokines IL-4 and IL-10 has not yet been studied in P0106-125-induced murine experimental autoimmune neuritis (EAN). We, therefore, addressed the functional relevance of these cytokines and signaling via the IL-4-associated transcription factor STAT6. The clinical course of P0106-125-induced EAN in mice deficient for IL-10(0/0), IL-4(0/0), or STAT6(0/0) was significantly aggravated compared with that of wild-type control mice. In addition, treatment of P0106-125-immunized C57BL/6 mice at the onset of clinical symptoms with a monoclonal IL-10 neutralizing antibody aggravated symptoms and prolonged disease to a similar degree as in IL-10(0/0) mice. This exacerbated course was attributed to a more prominent Th1 immune response associated with a persistent M1 milieu in the sciatic nerve and in the regional and systemic lymphatic system. These data suggest a Th2-polarized milieu being required to prevent axonal damage of the sciatic nerve and to terminate the P0106-125-specific immune response in EAN. Beyond the already known role of macrophages as pathogenic effector cells in EAN, these data suggest that M2-differentiated macrophages do not damage and may even protect neural tissues in EAN. Thus, these data highlight the pathogenetic relevance of the macrophage polarization status in EAN. Therapeutic modulation of immune responses from an M1 toward an M2 milieu may be a promising novel strategy in peripheral nervous system neuritis.

Diagnostic value of intraoperative histopathological examination of the sentinel nodes in breast cancer and skin melanoma—Preliminary results of single centre retrospective study

ObjectiveIntraoperative histopatological examination of the sentinel nodes enables selection of patients who need dissection of the regional lymphatic system during the same operation. The aim of this study is to evaluate the diagnostic value of intraoperative histopathological examination of the sentinel nodes in breast cancer and skin melanoma. Intraoperative histopathology of the sentinel nodes as a diagnostic method is used in patients with melanoma and breast cancer. Recent studies have proved it to be an effective method for evaluating the nodes in the final histopathology. Intraoperative histopathological examination of the sentinel nodes is not performed routinely and there is no clear position on this issue. In this paper we try to prove that intraoperative test gives patients the simultaneous benefits of removal of regional lymph nodes metastases and earlier initiation of adjuvant therapy. MethodsThe study comprises 137 patients with breast cancer and 35 patients with malignant skin melanoma. Sentinel nodes were intraoperatively sectioned and examined by means of the imprint method and frozen section evaluation. The patients with positive sentinel nodes underwent immediate dissection of regional lymph nodes. Those with negative sentinel nodes diagnosed in the intraoperative examination, but positive in final pathologic results, underwent subsequent dissection of regional lymph nodes. Results60 sentinel lymph nodes were found in 35 patients with skin melanoma. In 3 patients, 3 sentinel lymph nodes were false negative in the intraoperative histopathological examination. No false positive sentinel lymph nodes were found. 249 sentinel lymph nodes were found in the intraoperative histopathological examination in 137 patients with breast cancer. There were no false positive sentinel nodes, but there were 7 false negative sentinel nodes. In this study, only 5 (3.6%) patients with breast cancer and 3 (8.5%) patients with skin melanoma required another regional operation. ConclusionThe method of intraoperative histopathological evaluation of the sentinel nodes enables identification of metastases in these lymph nodes and gives a possibility to carry out a one-step regional lymphadenectomy and start the adjuvant therapy earlier.

Unusual Spreading of Colon Adenocarcinoma into the Right Hip Area: A Case Report

Adenocarcinoma is the most common colon cancer type. This form of colonic neoplasms usually metastasizes initially to regional lymphatic system and through the blood circulation to the lungs and liver, while other forms of expansion and involvement of other organ systems are less common. Extraluminal carcinoma is very rare. Only a few authors describe the direct spread of cancer to adjacent structures and organs. In this paper we present a case of a 76-year old patient with tumor mass extending from the colon to the right hip area “per continuitatem”. The patient had no symptoms and signs that would indicate the presence of neoplastic process in the colon. Only a discomfort in right leg was present and finally tumor mass was visualized. Biopsy and patohistology findings confirmed final diagnosis and type of tumor in the right hip region. Pathohistologicaly tumor was adenocarcinoma.

Preparation and animal experiment of lymphatic system-targeted contrast agent in magnetic resonance imaging

Macromolecular conjugates of Dextran-DTPA-Gd were synthesized in two ways. One is that Dextran reacted with DTPA anhydride using DMAP as catalytic agent, the other is that Dextran reacted with DTPA using DMAPEDC ·HCl as catalytic agents. The best reaction conditions were obtained by comparing the weight content of Gd and water-solubility of the products. The product with higher content by weight of Gd (16.1%) and good water-solubility was obtained and characterized by FTIR and particle size analysis (Size distribution ranged from 100 to 150 nm, 130 nm in average). In animal experiments, the MRI of Dextran-DTPA-Gd was evaluated in comparison with the MRI of Magnevist as positive control. The signal intensities of the regional lymphatic system were qualitatively assessed by the Time-Enhancing Rate curve. The results indicated that Dextran-DTPA-Gd obviously had higher signal enhancement (maximum enhancing rate to 314%) than that of Magnevist, and can be taken up selectively by lymphatic system and showed the potential as MRI contrast agents in lymphatic system as well.

Sentinel lymph node biopsy in breast cancer surgery

Axillary lymph node status is one of the most reliable prognostic factors of long-term survival in breast cancer surgery. Metastatic involvement of the axillary lymph nodes is also crucial in the decision making of potentially useful adjuvant treatment. Until the last decade, Axillary Lymph Nodes Dissection (ALND) was performed in order to obtain the regional lymphatic system staging. In case of non-metastatic spread, that kind of surgery was limited only to this purpose; no further oncological benefits were obtained and the patients were exposed to several comorbidities affecting this type of surgery. Complications after ALND are reported in 15-30% of cases. They are well known and range from early bleeding, infection, symptomatic nerve damage, and longstanding limb lymph-edema with an incredible impairment of the quality of life.The Sentinel Lymph Node (SLN) theory holds that the SLNs are the first nodes draining lymph from an anatomic region (i.e. the breast) where metastatic disease will most likely to be found. If that node is found to be cancer free, the entire lymphatic system is likely to be cancer free; if it is metastatic, there is an elevated chance of finding more metastatic nodes. Thanks to the application of this hypothesis, several patients over the last 10-15 years have avoided unnecessary major demolitive surgery. To obtain accurate evaluation of the SLN a multidisciplinary dedicated team is necessary. This procedure has been internationally validated and the false negative rate is nowadays less than 5% when performed by expert hands. Dedicated breast surgeons working in a high-volume centres are necessary to reach satisfactory confidence in performing this very specialised procedure in order to obtain an accurate staging. The number of women presenting to the breast oncology units is continuously increasing and the implementation of screening programs has been crucial in detecting numerous patients (more than 75%) with early disease and non-metastatic axillary lymph nodes. The practice of the SLN is clearly able to offer those patients an accurate staging with low comorbidities, preserving their quality of life.

Sentinel Lymph Nodes

Sentinel Lymph Nodes

Sentinel node mapping

Key content Cancers involving the regional lymphatic system around the primary site have a poor prognosis. The sentinel node is understood to be the first node to which lymphatic drainage occurs from an organ or area of skin. The sentinel node can be identified using a blue dye or radiolabel. If the sentinel node does not contain metastatic tumour, the risk of involved regional nodes is small. The technique has the potential to reduce the morbidity associated with regional lymphadenectomy. Learning objectives To understand the sentinel node concept. To understand the role of sentinel node biopsy in vulval, cervical and endometrial cancer. Ethical issues Randomised controlled trials should be performed before the technique can be introduced into routine practice. Please cite this article as: Acheson N. Sentinel node mapping. The Obstetrician & Gynaecologist 2007;9:270–275.

The Healing of Tibial Fracture and Response of the Local Lymphatic System

Damage of tissues by mechanical injury and inflammation is followed by reaction of the regional lymphoid tissue, lymphatics, and lymph nodes. In our previous lymphoscintigraphic studies, we showed that closed fractures of a lower limb cause reaction of the local lymphoid tissue. There was dilation of lymphatics draining the site of the fracture and enlargement of inguinal lymph nodes. These changes persisted even after clinical healing of the fracture. In the long-lasting nonhealing fractures, the lymphoscintigraphic pictures were different. The draining lymphatics became obliterated, and the lymph nodes disappeared. In this study, we tried to correlate the lymphoscintigraphic images, reflecting the immune events at the fracture site, with the immunohistochemical observations of the biopsy specimens obtained during corrective operations from the healing and nonhealing fracture gaps. Thirty-eight patients with closed fracture of the tibia without traumatic skin changes were studied. We confirmed that closed tibial fracture evokes response of the regional lymphatic system. Normal fracture healing with immune cell infiltrates and foci of ossification was accompanied by dilated lymphatics and enlarged lymph nodes. Prolonged nonhealing fracture with lack of cellular reaction in the gap proceeded with decreased mass of lymph nodes. This study provides evidence for existence of a functional axis between wound of bone and surrounding soft tissue and the local lymphatic (immune) system. We hypothesize that the fast healing is regulated by influx into the wound of lymph node regulatory cells, whereas prolonged healing causes gradual exhaustion of the regional lymph node functional elements, and reciprocally impairment in sending regulatory cells to the fracture gap.

Targeting colloidal particulates to thoracic lymph nodes

Thoracic lymphatics and lymph nodes can be affected by cancer and other diseases. Micro- or nanoparticulates are used as carriers for therapeutic agents. We investigated the lymphatic distribution after intrapleural administration of three different particulates. Various micro- and nanoparticles of charcoal, polystyrene and poly(lactide-co-glycolide) were administered into the pleural space of rats to study the lymphatic distribution of particles from the pleural cavity to the thoracic lymph nodes. Experimental animal models included healthy rats, rats following pneumonectomy and rats bearing orthotopic lung cancer to mimic relevant clinical scenarios and pathophysiology. Macroscopic examination, light microscopy, fluorescence microscopy complemented by transmission electron microscopy analysis of the lymphatic tissue allowed precise mapping and detection of the particulates in the thoracic lymphatic system. We found that (1) the particles studied are cleared by the regional thoracic lymphatic system when placed in the pleural space; (2) the lymphatic uptake occurred as early as 3h after injection and is primarily through the parietal pleura; (3) the transport of particles to regional lymph nodes was consistently found in all three animal models; (4) particles of 0.7-2 microm in size give the best lymphatic distribution. Regional thoracic lymphatics and lymph nodes can be accessed by colloidal particles injected into the pleural space.

Identification of the regional lymphatic system of the gallbladder by vital staining.

In 21 patients with biliary tract cancer dye was injected into the lymphatic system of the gallbladder to determine the extent of its regional lymph nodes. A volume of 0.1-0.3 ml 1 per cent indigo carmine solution was injected directly into lymphatic vessels of the gallbladder in eight patients and into lymph nodes (cystic node or pericholedochal nodes) in 13 patients during radical surgery for biliary tract cancer. The lymphatic system was visualized in a total of 14 patients. The dye descended around the bile duct, flowed into the cystic node, the pericholedochal nodes and the lymph nodes posterior to the head and neck of the pancreas, and finally reached the interaortocaval nodes adjacent to the left renal vein. The stained lymphatic tissue was regarded as the regional lymphatic system of the gallbladder. These nodes should be completely resected during radical surgery for gallbladder cancer.