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PubMed1994

Compartment-oriented microdissection of regional lymph nodes in medullary thyroid carcinoma.

Lymph node metastases have been proven to be the main prognostic factor in medullary thyroid carcinoma (MTC). This retrospective study was undertaken to evaluate the efficiency of two surgical techniques of regional lymph node dissection with regard to the normalization of pentagastrin-stimulated serum calcitonin level and patient survival: selective lymphadenectomy, i.e., the excision of macroscopically or microscopically involved lymph nodes, versus a systematic lymphadenectomy performed by the new technique of a compartment-oriented microdissection. From 1970 to 1990, 82 patients with sporadic (n = 57) and hereditary (n = 25) MTC underwent a total of 142 operations including 63 selective lymphadenectomies and, since 1986, 35 systematic lymphadenectomies. The study revealed that in node-positive MTC the rate of interventions with a postoperative normalization of pentagastrin-stimulated serum calcitonin was higher after systematic lymphadenectomy (29.2%) than after selective lymphadenectomy (8.5%) (P < 0.01). The rate of patients undergoing repeat surgery due to a recurrence of MTC was 48% after selective lymphadenectomy and 10% after systematic lymphadenectomy. Survival was significantly better for patients after systematic versus selective lymphadenectomy (P < 0.005). This study thus emphasizes that systematic lymphadenectomy, using the technique of a compartment-oriented microdissection of cervicomediastinal lymph nodes, represents the preferred surgical treatment as well as the optimum technique in primary as well as secondary node-positive MTC.

Adolescent↗

PubMed1986

The early postnatal development of the primary immune response in TNP-KLH-stimulated popliteal lymph node in the rat.

The popliteal lymph nodes were removed from young rats of various ages five days after a single immunization with TNP-KLH in the hind footpads. Cryostat sections of the lymph nodes were investigated by means of enzyme- and immunohistochemical techniques at the light-microscopical level. The presence and localization of anti-TNP antibody-containing cells were examined using a new technique to visualize specific antibodies. Moreover, the development of the lymph nodes following exogenous antigenic stimulation was compared with that of unstimulated lymph nodes. Specific antibody-containing cells could not be found before day 15 after birth, in rats immunized at day 10. From that time these lymphoid cells were located primarily at the border between cortex and medulla. Younger popliteal lymph nodes showed only aspecific immunoglobulin-containing lymphoid cells. With age, the number of specific antibody-containing cells tended to increase. These cells were more mature, according to morphological criteria and were located nearer the medulla. The first primary follicles were seen at day 19, as was the case in unstimulated animals. The first secondary follicles, containing germinal centers, were detected at day 23, whereas in unstimulated popliteal lymph nodes they were never found. Trapping of immune complexes could not be demonstrated before day 33 after birth. The later appearance of this phenomenon might be a consequence of the techniques applied to demonstrate specific antibody-containing cells.

Aging↗

PubMed2005

Identifying risk factors for complications following sentinel lymph node biopsy for melanoma.

BACKGROUND: Sentinel lymph node biopsy has become routine in the staging of patients with cutaneous melanoma and is presumed to have fewer complications than elective regional lymph node dissection (RLND). However, little information is available to refute or support this assumption. HYPOTHESIS: Risk factors for complications following sentinel lymph node biopsy (SLNBX) can be identified. DESIGN: Retrospective medical record review. PATIENTS AND METHODS: The medical records of 339 consecutive patients undergoing SLNBX for melanoma between 1996 and 2003 at our institution were reviewed for complications. RESULTS: In our series of 339 patients, 20 complications (5.9%) were observed following SLNBX compared with 15 (19.5%) of 77 patients undergoing RLND during the same period (P<.001). Seroma formation, transient nerve injuries, and minor wound infections were the most frequently observed complications in patients undergoing SLNBX. In contrast, chronic lymphedema and wound infections were the most frequent complications observed in patients undergoing RLND. Patients with comorbid medical conditions had more complications following either SLNBX or RLND than those without. The number of lymph nodes excised and the placement of closed-suction drainage were associated with an increased incidence of complications following SLNBX but not RLND. The incidence of annual complications inversely correlated with the cumulative number of SLNBXs performed during this period. CONCLUSIONS: Sentinel lymph node biopsy can be performed with a low incidence of complications. Experience with SLNBX decreases complications. Patients with more than 1 sentinel lymph node excised or a closed-suction drain placed at the time of SLNBX are at an increased risk of complications.

Chi-Square Distribution↗

PubMed2002

Sentinel lymph node identification in breast cancer patients.

PURPOSE: To evaluate the predictive value of sentinel lymph node biopsy versus axillary node dissection on lymph node status in patients with T1-T2 breast cancer. MATERIAL AND METHODS: Twenty-nine patients with T1 and 12 with T2 breast carcinoma and clinically N0 axillary lymph nodes, underwent lymphoscintigraphy following the administration of 99mTc-human albumin nanocolloids. The tracer was injected subdermally, over the tumor mass, in the 34 patients with palpable lesions and peritumorally (n=3) or intratumorally (n=4), under stereotactic or ultrasound guidance, in the 7 patients with non-palpable lesions. Anterior and lateral planar images were acquired 15 min after the injection of the tracer and repeated every 30 min up to 3 hr until identification of sentinel lymph node. At the end of the scintigraphic study, sentinel node skin projection was marked using a dermographic pen. Eighteen hours after lymphoscintigraphy, sentinel lymph node was identified and removed during surgery by hand-held gamma probe, then, the remaining axillary lymph nodes were dissected. All surgical specimens underwent histologic examination. Sentinel lymph nodes free of metastasis at histology, underwent additional examination with immunohistochemistry using monoclonal antibodies against cytokeratin and EMA to search for micrometastases. RESULTS: Sentinel lymph node was identified in the 34 patients injected subdermally and in the 3 patients injected peritumorally, while it remained undetected in the 4 patients injected intratumorally except for one case in which it was isolated by radioguided surgery but not scintigraphically. Sentinel nodes resulted free of metastases both at histology and immunohistochemistry in 32 cases and metastatic in 6. In the 32 patients with non-metastatic sentinel lymph nodes the other axillary nodes were also free of metastases. Among the 6 metastatic sentinel lymph nodes, in 3 cases they were the only metastatic nodes of the axilla while in the other 3 cases metastases were spread to other axillary nodes. CONCLUSIONS: In agreement with previous studies, our results showed that sentinel lymph node radioguided biopsy is a simple and reliable method for predicting axillary lymph nodes status and for avoiding axillary dissection in early breast cancer patients with sentinel node free of metastases.

Adult↗

PubMed2005

Fluorescence navigation with indocyanine green for detecting sentinel lymph nodes in breast cancer.

BACKGROUND: Sentinel lymph node biopsy using a vital dye is a convenient and safe method to assess lymph node status in breast cancer. However, intensive training is necessary to obtain a satisfactory detection rate and to avoid false-negative results. This paper presents a novel method using indocyanine green fluorescence imaging to detect sentinel lymph nodes. METHODS: Fluorescence images were obtained using a charge coupled device camera with a cut filter as the detector, and light emitting diodes at 760 nm as the light source. When indocyanine green was injected around the areola, subcutaneous lymphatic channels draining from the areola to the axilla were visible by fluorescence within a few minutes. The sentinel lymph node was then dissected by fluorescence navigation. RESULTS: Sentinel lymph node biopsy using the present method was performed on eighteen patients. Subcutaneous lymphatics were detectable by fluorescence in all patients, and sentinel nodes were successfully identified in 17 of 18 cases (detection rate:94%). It was possible to detect the lymphatic channels and nodes receiving indocyanine green with higher sensitivity by the fluorescence signal than by the green color. CONCLUSION: Sentinel node biopsy guided by indocyanine green fluorescence imaging is a promising technique for further clinical exploration.

Axilla↗

PubMed1998

In vitro investigation of lymph node metastasis of colorectal cancer using ultrasonic spectral parameters.

Lymph node involvement is one of the major factors affecting the prognosis of colorectal cancer. Various imaging methods, including ultrasound and computed tomography, are not sufficiently sensitive or specific for reliably determining lymph node involvement. We investigated the feasibility of using ultrasonic tissue characterization (UTC) based on spectrum analysis of backscattered echo signals for diagnosing lymph node metastasis of colorectal cancer in vitro. Forty lymph nodes, including 17 metastatic and 23 nonmetastatic nodes, from 11 colorectal cancer operations were investigated. Lymph nodes were scanned using a clinical instrument; B-mode imaging was performed for each lymph node, and radiofrequency (RF) data were acquired. The UTC parameters, slope and intercept, were calculated from the normalized power spectrum of the backscattered echo signals from each lymph node. The mean values of UTC parameters of metastatic and nonmetastatic lymph nodes were compared. The accuracy of UTC in distinguishing metastatic from nonmetastatic lymph nodes was calculated using discriminant analysis. Receiver operating characteristic (ROC) analysis was performed to compare the classification efficacy of UTC and B-mode ultrasound. UTC parameters demonstrated a significant difference in parameter values between metastatic and nonmetastatic lymph nodes. The overall accuracy in diagnosing the lymph node metastasis was 87.5% for UTC and 77.5% for B-mode ultrasound. ROC analysis produced an ROC curve area of 0.92 or 0.89 for UTC (depending on the performance-assessment algorithm) and 0.84 for B-mode ultrasound, which indicated that UTC performed markedly better than B-mode ultrasound in diagnosing metastatic lymph nodes. The advantages of UTC over conventional B-mode ultrasound in discriminating metastatic lymph nodes from nonmetastatic lymph nodes are extremely encouraging, and warrant an in vivo UTC study.

Aged↗

PubMed1986

Percutaneous inoculation of lymph nodes.

Injections into rat lymph nodes are easily performed percutaneously, without the need for a skin incision, if the nodes are enlarged in advance. The requisite enlargement of the popliteal lymph node can be obtained in 2 or 3 weeks by a single injection of tin powder or other particulate material into the foot. This method may be especially useful when multiple intranodal inoculations are contemplated.

Animals↗

PubMed1992

Lymph node findings in generalized mastocytosis.

Lymph nodes from 21 cases of generalized mastocytosis were studied histologically to confirm or exclude mast cell infiltration, and to investigate their micro-architecture. Mast cell infiltrates were detected in 17 (80%) of the lymph nodes and were found mainly in the medullary cords and sinuses. Diffuse infiltration was seen in 14 cases and focal infiltration in three cases. The following pathological findings were frequently observed: germinal centre hyperplasia (n = 14), which is probably a nonspecific finding; and hyperplasia of small blood vessels, which sometimes resembled high endothelial venules (14), eosinophilia (8), plasmacytosis (7) and collagen fibrosis (6), all of which may well be related to the effects of mediators released by mast cells. Infiltrates of acute or chronic myeloid leukaemia were seen in six lymph nodes. Division of the cases into two prognostically different groups, i.e. systemic mastocytosis, in which the skin lesions of urticaria pigmentosa are present and the prognosis is favourable, and malignant mastocytosis, in which there is no cutaneous involvement and the prognosis is poor, revealed that all six lymph nodes exhibiting leukaemic infiltrates came from the malignant mastocytosis group; eosinophilia, plasmacytosis and fibrosis were seen significantly more often in malignant than in systemic mastocytosis, but blood vessel hyperplasia and germinal centre hyperplasia were encountered with the same high frequency in both groups; and mast cell atypia tended to be more pronounced in malignant mastocytosis; this diagnosis could therefore easily be missed without naphthol AS-D chloroacetate esterase staining.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗

PubMed2000

Pathologic evaluation of sentinel lymph nodes in colorectal carcinoma.

BACKGROUND: The identification of lymph node metastases in colorectal resection specimens is necessary for accurate tumor staging. However, routine lymph node dissection by the pathologist yields only a subset of nodes removed surgically and may not include those nodes most directly in the path of lymphatic drainage from the tumor. Intraoperative mapping of such sentinel lymph nodes (SLNs) has been reported in cases of melanoma and breast cancer. We applied a similar method to cases of colorectal carcinoma, with emphasis on the pathology of the SLNs. METHODS: Eighty-three consecutive patients with colorectal carcinoma were evaluated after intraoperative injection of 1 to 2 mL of 1% isosulfan blue dye (Lymphazurin) into the peritumoral subserosa. Blue-stained lymph nodes were suture-tagged by the surgeon within minutes of the injection for identification by the pathologist, and a standard resection was performed. Designated SLNs were sectioned at 10 levels through the block; a cytokeratin immunostain (AE1) was also obtained. To evaluate the possibility that increased detection of metastases in the SLN might be solely due to increased histologic sampling, all initially negative non-SLNs in the first 25 cases were sectioned also at 10 levels. RESULTS: Sentinel lymph nodes were identified intraoperatively in 82 (99%) of 83 patients and accounted for 152 (11.9%) of 1275 lymph nodes recovered, with an average of 1.9 SLNs per patient. A total of 99 positive lymph nodes (38 positive SLNs and 61 positive non-SLNs) were identified in 34 node-positive patients. The SLNs were the only site of metastasis in 17 patients (50%), while 14 patients (41%) had both positive SLNs and non-SLNs. Three patients (9%) had positive non-SLNs with negative SLNs, representing skip metastases. In patients with positive SLNs, 91 (19%) of 474 total lymph nodes and 53 (12%) of 436 non-SLNs were positive for metastasis. In patients with negative SLNs, 8 (1%) of 801 total lymph nodes and 8 (1.2%) of 687 non-SLNs were positive for metastasis. Multilevel sections of 330 initially negative non-SLNs in the first 25 patients yielded only 2 additional positive nodes (0. 6%). All patients with positive SLNs were correctly staged by a combination of 4 representative levels through the SLN(s) together with a single cytokeratin immunostain. CONCLUSIONS: Intraoperative mapping of SLNs in colorectal carcinoma identifies lymph nodes likely to contain metastases. Focused pathologic evaluation of the 1 to 4 SLNs so identified can improve the accuracy of pathologic staging.

Adult↗

PubMed1985

Uptake mechanism of interstitially injected 99mTc-labeled antimony trisulphide colloid in the popliteal lymph node of rabbits.

The right popliteal lymph node was studied in rabbits by well counting, histoautoradiography and electron microscopy, after interstitial injection of 99mTc-labeled antimony trisulphide (Sb2S3) colloid into the right hind pad. The highest radioactivity concentration (96.8%/g) was measured 6 hr following injection. At 24 hr, the concentration had dropped to nearly half of the maximum (51.5%/g). At each time, only a single or a few lymph node sectors were found to contain 99mTc. Initially, the radioactivity distribution pattern in the draining lymph node was stripy. Beginning at 15 min p.i., there was a progressive change from stripy to focal radioactivity distribution pattern. Until 6 hr after injection, the bulk of radioactivity was trapped by macrophages in the lumen and wall of the lymph node sinus system, predominantly in medullary sinuses. Surprisingly, at 24 hr the majority of labeled cells were eosinophilic polymorphonuclear leukocytes located in medullary sinuses and medullary cords. Up to 24 hr p.i., no accumulation of radioactivity could be detected in the cortical and paracortical lymph node parenchyma. In conclusion, interstitially injected 99mTc-Sb2S3 colloid is not homogeneously but sectorially distributed in the draining lymph node. Moreover, both macrophages and eosinophilic polymorphonuclear leukocytes are involved in the filtration process.

Animals↗

PubMed1986

Breast cancer metastasis to intramammary lymph nodes.

Metastatic disease to the intramammary lymph nodes from breast cancer may be seen mammographically. In the four cases reviewed, the affected intramammary lymph nodes were enlarged (1 cm or greater in diameter), homogeneous, and well circumscribed. All lacked the lucent center or hilar notch characteristic of benign intramammary nodes. Differentiation of malignant from benign causes of intramammary lymph node enlargement, such as inflammation or hyperplasia, is impossible by mammography. Biopsy is recommended for all intramammary lymph nodes of 1 cm or greater that are not fat infiltrated unless the patient clearly has an associated dermatitis or mastitis. Metastatic disease to the intramammary lymph nodes may be the first clinical and/or mammographic sign of breast cancer and may significantly affect prognosis.

Aged↗

PubMed2002

[Sentinel lymph node mapping in colorectal cancer].

UNLABELLED: Sentinel lymph node mapping has already been accepted as part of the treatment for malignant melanomas of the skin and in breast carcinomas. The status of lymph nodes is an important prognostic marker in colorectal carcinoma as well. The authors tried the feasibility of this technique in colorectal carcinomas. The technique is analogous to the one used in breast cancer and melanoma: 2 ml of 2.5% Patentblau dye was given subserosally around the tumor. After resection the specimen was immediately sent to pathology where the lymph nodes were removed. This technique has been tried on 31 patients, 22 with colonic and 9 with rectal tumors. Of these patients, 15 were Dukes stage C, 14 were Dukes stage B and 2 were Dukes stage A. An average 4.3 blue lymph nodes were found in colon tumors and 5.4 in rectal tumors and an average 14 unstained lymph nodes were found in colon tumors, and 7 in rectal tumors. The blue nodes were predictive of the nodal status in 9 of the 15 Dukes stage C patients. In these cases the blue lymph nodes contained metastases and there were 2 cases where metastases were limited to the blue lymph nodes. SUMMARY: The authors found a high false negative rate for lymphatic mapping with the vital dye technique, therefore they try to change the method according to that used by Saha et al. The aim of sentinel node identification in colorectal carcinomas would be improved staging rather than reducing of the extent of lymphadenectomy. The role of lymphatic mapping in large bowel cancers needs further investigations. Until the results are reliable, as many lymph nodes as possible have to be excited and sent for histology.

Aged↗

PubMed1994

Localization of tumor-reactive lymph node lymphocytes in vivo using radiolabeled monoclonal antibody.

BACKGROUND: Lymph node lymphocytes vary in their responsiveness to tumor. A technique has been developed that uses radiolabeled monoclonal antibody (MoAb) against the tumor-associated mucin, TAG-72, and a gamma-detecting probe by which lymph nodes containing microscopic tumor and/or shed TAG-72 can be identified in vivo. The immunologic characteristics of these lymph nodes were examined. METHODS: Patients with colon cancer received 125I-labeled MoAb CC49 by intravenous injection preoperatively. During laparotomy lymph nodes that appeared normal on inspection and palpation but which contained radiolabeled MoAb were identified using a hand-held gamma-detecting probe. These lymph nodes and other lymph node and tumor specimens were resected for analysis. RESULTS: Lymph nodes identified by the probe were found by immunohistochemical studies to contain microscopic tumor and/or shed antigen associated with germinal centers. They were characterized by greater CD4+:CD8+ ratios, rates of expansion, and cytolytic activity compared with lymphocytes from lymph nodes with macroscopic tumor, noninvolved lymph nodes, and tumors. All lymph node lymphocytes identified by the probe demonstrated significant proliferative responses to autologous tumor and, in contrast to lymphocytes from noninvolved lymph nodes, significant proliferative responses to allogeneic TAG-72+ tumor cells and to soluble TAG-72+ mucin. CONCLUSIONS: By locating lymph nodes with microscopic tumor and/or shed antigen, the use of radiolabeled MoAb in vivo can be used to reproducibly identify tumor-reactive lymph node lymphocytes. This technique may be useful in identifying cells for use in adoptive immunotherapy programs and in studying the regulation of immune responses in vivo.

Antibodies, Monoclonal↗

PubMed2000

Aspiration biopsy and the clinical management of patients with malignant melanoma and palpable regional lymph nodes.

BACKGROUND: The presence of lymph node metastases in patients with malignant melanoma implies a significant decrease in survival. The authors investigated the efficacy of fine-needle aspiration biopsy (FNAB) in the diagnosis of metastatic malignant melanoma in 115 patients with melanoma and clinically suspicious regional lymph nodes. METHODS: One hundred thirty-three FNABs were performed by cytopathologists after referral from surgeons or oncologists using a 25-gauge or 27-gauge needle. RESULTS: The cytologic diagnosis was negative in 35, atypical in 1, suspicious in 2, and positive for malignant melanoma in 95. Regional lymph node dissections were performed in 78 patients. Of these, 70 positive FNABs were confirmed with no false-positive results. The atypical FNAB was proven positive for malignant melanoma at surgery. Of the two suspicious FNABs, one was confirmed as positive and one showed dermatopathic lymphadenopathy. Of the 35 negative FNAB specimens, 5 patients underwent surgery; 3 FNABs were found to be negative and 2 FNABS were falsely negative. Twenty patients with negative aspirates were followed clinically for 22-45 months (mean, 32 months); 19 patients had no evidence of disease and 1 patient died of disseminated melanoma. CONCLUSIONS: FNAB of palpable lymphadenopathy in patients with malignant melanoma can provide a rapid and accurate assessment of lymph node status and expedite the therapeutic management of these patients.

Adult↗

PubMed1986

Distinctive peripheral lymph node hyperplasia of young cats.

Peripheral lymph node enlargement was found in 14 of a series of 132 feline lymph node biopsy specimens. Six of nine cats tested had antibodies for feline leukemia virus (FeLV). Half of the cats were clinically normal while the remainder had fever, lethargy, anorexia, and hepatosplenomegaly. There was severe distortion of lymph nodal architecture with variable loss of discernible follicles and sinuses. Histiocytes, lymphocytes, immunoblasts, and plasma cells were present in expanded paracortical regions which encroached on, and occasionally effaced, lymphoid follicles. Postcapillary venules were numerous and prominent throughout the paracortex. The lymphadenopathy was most commonly transient (86% of cases) with subsequent development of lymphoma in one cat. Lymph nodes from seven kittens with experimental FeLV infection were compared with spontaneously enlarged lymph nodes; four of seven had B and T lymphocyte hyperplasia with normal nodal architecture. Three had partial loss of nodal architecture as a result of expanded paracortical regions populated largely by histiocytes and lymphocytes. Proliferation of postcapillary venules was not prominent in nodes from FeLV-infected cats. The cause of spontaneous lymph node hyperplasia of young cats was not determined. However, the similarity of lesions to those of kittens with experimental FeLV infection and the association with FeLV by serologic tests in six of nine cats suggest that this retrovirus may be involved in the pathogenesis of the lesion.

Animals↗

PubMed2003

Comparison of pathologist-detected and automated computer-assisted image analysis detected sentinel lymph node micrometastases in breast cancer.

Sentinel lymph node biopsy has stimulated interest in identification of micrometastatic disease in lymph nodes, but identifying small clusters of tumor cells or single tumor cells in lymph nodes can be tedious and inaccurate. The optimal method of detecting micrometastases in sentinel nodes has not been established. Detection is dependent on node sectioning strategy and the ability to locate and confirm tumor cells on histologic sections. Immunohistochemical techniques have greatly enhanced detection in histologic sections; however, comparison of detection methodology has not been undertaken. Automated computer-assisted detection of candidate tumor cells may have the potential to significantly assist the pathologist. This study compares computer-assisted micrometastasis detection with routine detection by a pathologist. Cytokeratin-stained sentinel lymph node sections from 100 patients at the University of Vermont were evaluated by automated computer-assisted cell detection. Based on original routine light microscopy screening, 20 cases that were positive and 80 cases that were negative for micrometastases were selected. One-level (43 cases) or two-level (54 cases) cytokeratin-stained sections were examined per lymph node block. All 100 patients had previously been classified as node negative by using routine hematoxylin and eosin stained sections. Technical staining problems precluded computer-assisted cell detection scanning in three cases. Computer-assisted cell detection detected 19 of 20 (95.0%; 95% confidence interval, 75-100%) cases positive by routine light microscopy. Micrometastases missed by computer-assisted cell detection were caused by cells outside the instrument's scanning region. Computer-assisted cell detection detected additional micrometastases, undetected by light microscopy, in 8 of 77 (10.4%; 95% confidence interval, 5-20%) cases. The computer-assisted cell detection-positive, light microscopy-missed detection rate was similar for cases with one (3 of 30; 10.0%) or two (5 of 47; 10.6%) cytokeratin sections. Metastases detected by routine light microscopy tended to be larger (0.01-0.50 mm) than did metastases detected only by computer-assisted cell detection (0.01-0.03 mm). In a selected series of patients, automated computer-assisted cell detection identified more micrometastases than were identified by routine light microscopy screening of cytokeratin-stained sections. Computer-assisted detection of events that are limited in number or size may be more reliable than detection by a pathologist using routine light microscopy. Factors such as human fatigue, incomplete section screening, and variable staining contribute to missing metastases by routine light microscopy screening. Metastases identified exclusively by computer-assisted cell detection tend to be extremely small, and the clinical significance of their identification is currently unknown.

Breast Neoplasms↗

PubMed1998

Lymphatic uptake and biodistribution of liposomes after subcutaneous injection . IV. Fate of liposomes in regional lymph nodes.

The ability of clodronate-containing liposomes to deplete lymph nodes of macrophages was used as a tool to investigate the fate of liposomes in regional lymph nodes after subcutaneous (s.c.) administration. Reduced lymph node localization of liposomes in macrophage-depleted lymph nodes confirmed that phagocytosis by macrophages plays an important role in lymph node retention of liposomes. Depletion of macrophages had less effect on lymph node localization of small liposomes than on the lymph node localization of large liposomes. Inclusion of distearoylphosphatidylethanolamine (DSPE)-poly(ethyleneglycol) (PEG-PE) into the liposomes, which is known to oppose macrophage uptake, did not affect lymph node localization in macrophage-depleted or control lymph nodes. We conclude that PEG-liposomes retained by lymph nodes are also taken up by lymph node macrophages. Morphological observations visualizing the uptake of PEG-liposomes by lymph node macrophages support this conclusion.

Animals↗

PubMed1991

A detailed histological study on occult metastasis of the lymph nodes.

One representative microsection from each lymph node was carefully surveyed for metastasis in a routine examination. To scrutinize the existence of occult metastasis, three additional sections were then made from half of the remaining lymph node. A total of 1,698 lymph nodes taken from 55 patients with carcinoma of the esophagus, stomach, colon, thyroid or breast were thus reexamined histologically. The initial examination was not able to prove any metastasis in these lymph nodes. Upon reexamination, however, involvement by cancer cells was detected in 10 nodes of 7 patients. The maximum diameter of the metastatic foci varied from 0.2 mm to 1.3 mm and was less than 0.5 mm in more than half of the nodes. The metastatic patterns in the nodes were classified into three types, i.e., marginal sinus type, medullary sinus type and mixed type. The marginal sinus type was the most frequent, with the mixed type being next and the medullary sinus type being found in only one node. Accordingly, surgeons should keep the possibility of occult metastasis in mind and the marginal sinus of the lymph node should be carefully examined in order to detect any small foci of metastasis.

Humans↗