The lymph drainage of the neoplastic mammary glands in the bitch: a lymphographic study

The purpose of this investigation was to study the lymph drainage of the neoplastic mammary glands in the bitch using indirect lymphography. The main conclusions drawn from the study of 41 natural cases were as follows: the first or cranial thoracic and second or caudal thoracic neoplastic mammary glands usually drain into the ipsilateral axillary lymph nodes and rarely into the ipsilateral axillary and sternal lymph nodes, simultaneously. The third or cranial abdominal neoplastic mammary gland usually drains into the ipsilateral axillary and superficial inguinal lymph nodes simultaneously, but sometimes only cranially into the ipsilateral axillary lymph nodes. Rarely, it drains only caudally into the ipsilateral superficial inguinal and medial iliac lymph nodes, simultaneously. The fourth or caudal abdominal neoplastic mammary gland usually drains only caudally into the ipsilateral superficial inguinal lymph nodes. Rarely, it drains into the ipsilateral axillary and superficial inguinal lymph nodes simultaneously. The fifth or inguinal neoplastic mammary gland usually drains into the ipsilateral superficial inguinal lymph nodes but rarely, does it also drain into the ipsilateral popliteal lymph node and into a lymphatic plexus at the medial aspect of the ipsilateral thigh. Lymphatic connections between the neoplastic and adjacent normal mammary glands were demonstrated in only one case. The lymph drainage pattern of the neoplastic mammary glands is slightly different to that described in normal glands using the same radiographic method.     

The Lymph Drainage of the Mammary Glands in the Bitch: a Lymphographic Study. Part I: The 1st, 2nd, 4th and 5th Mammary Glands

The objective of this paper was to study the lymph drainage of the 1st, 2nd, 4th and 5th mammary glands in the bitch using indirect lymphography. The main conclusions drawn after the study of 67 normal lactating mongrel bitches were as follows: lymph drains from the first gland, usually to the axillary nodes, and, in few cases, to the axillary and superficial cervical nodes simultaneously. The second gland drains to the axillary nodes. The fourth gland usually drains to the superficial inguinal nodes, but it may, rarely, drain to the superficial inguinal and medial iliac nodes simultaneously. The fifth gland drains to the superficial inguinal nodes. Lymphatic connection between the mammary glands could not be demonstrated. Furthermore, it was confirmed that lymph can pass from one gland to another, through their common regional lymph nodes, by retrograde flow. It was demonstrated that there is a connection between the superficial inguinal lymph nodes from either side. It is suggested that lymphatic connection between the axillary and sternal nodes and between the axillary and bronchial nodes should be possible in some cases. Lymphatics of the mammary glands that cross the midline were not demonstrated.     

The Lymph Drainage of the Mammary Glands in the Bitch: a Lymphographic Study. Part II: the 3rd Mammary Gland

The objective of this investigation was to study the lymph drainage of the 3rd mammary gland in the bitch using indirect lymphography. The main conclusions drawn after the study of 62 normal lactating mongrel bitches were as follows: lymph usually drains from the third gland to the axillary and superficial inguinal nodes simultaneously, but in some cases it drains only cranially to the axillary nodes. It may, rarely, drain only caudally to the superficial inguinal nodes. A lymphatic connection between the mammary glands could not be demonstrated. It was demonstrated that there is a connection between the superficial inguinal lymph nodes on either side. It is suggested that lymphatic connection between the axillary and sternal nodes and the axillary nodes of both sides should be possible in some cases. Lymphatics of the mammary glands that cross the midline were not demonstrated. No relationship between the number of lymph nodes and the body size of the dog could be demonstrated.     

99mTc-labeled dextran for mammary lymphoscintigraphy in dogs

Lymphoscintigraphy is the technique of choice for sentinel lymph node detection in women with early breast cancer, but there is limited information evaluating the value of this technique in animals. We investigated mammary lymphatic drainage in 25 young female mongrel dogs by intramammary injection of 18.5 MBq of 99mTc-dextran (70,000 Da). Lymph node anatomical referencing was obtained using an external marker, bone scintigraphy, or scintiscanning the body contour. Cranial and caudal thoracic mammary glands drained into the cranial sternal lymph node and axillary lymph center. The cranial thoracic mammary gland also drained into the superficial cervical lymph node in two of five animals. The cranial abdominal gland was drained by the axillary lymph center. The caudal abdominal mammary gland was drained by the superficial inguinal lymph node in all animals and simultaneously by medial iliac lymph nodes in four of five animals. In one dog, this mammary gland was also drained by the mediastinal and the superficial cervical lymph nodes. The inguinal mammary gland was drained by superficial inguinal lymph nodes and simultaneously via the medial iliac lymph node in one animal. Lymphatic communications between lymph nodes were identified in 11 of 25 (44%) animals. 99mTc-dextran mammary lymphoscintigraphy was easy and rapid to perform and may provide valuable information for further studies.     

COMPUTED TOMOGRAPHY AND RADIOGRAPHIC INDIRECT LYMPHOGRAPHY FOR VISUALIZATION OF MAMMARY LYMPHATIC VESSELS AND THE SENTINEL LYMPH NODE IN NORMAL CATS

The potential of computed tomography indirect lymphography (CT‐indirect lymphography) and radiographic indirect lymphography to demonstrate the draining lymphatic vessels and sentinel lymph node of normal mammary glands was tested in 31 healthy female cats. The lymphatic drainage of each mammary gland was studied initially by CT‐indirect lymphography after intramammary injection of 0.5 ml of iopamidol, followed by images acquired at 1, 5, 15, and 30 min after injection. One day after CT‐indirect lymphography, the lymph drainage of the mammary gland was assessed using radiographic indirect lymphography after intramammary injection of 0.5 ml of ethiodized oil followed by radiographs made at 1, 5, 15, 30, 45, and 60 min after injection. The time between intramammary injection and opacification of the draining mammary lymphatic vessels and the sentinel lymph node, the duration of adequate opacification of the draining mammary lymphatic vessels and of the sentinel lymph node and also the number and course of draining mammary lymphatic vessels and location of sentinel lymph node were compared for CT‐indirect lymphography vs. radiographic indirect lymphography in each examined gland. This results suggest that radiographic indirect lymphography is easy to perform and can be used for accurate demonstration of the draining lymphatic pathways of mammary glands in radiographs made at 5–30 min after injection. However, CT‐indirect lymphography was able to better demonstrate small lymphatic vessels and accurately define the exact topography of the sentinel lymph node in images acquired at 1 min after injection.     

Lymphatic Drainage on Healthy and Neoplasic Mammary Glands in Female Dogs: Can it Really be Altered?

The purpose of this research was to study the mammary lymphatic drainage under a macroscopic and mesoscopic view, comparing the vascular pattern of healthy and neoplasic mammary glands injected with drawing ink alcoholic and fluorescein solutions, in 46 mongrel female dogs. The results pointed out that the thoracic gland is drained by the axillary lymph centre, but in mammary neoplasia either superficial cervical or ventral thoracic lymph centres can be involved. Cranial and caudal abdominal glands may be drained by the axillary, inguinofemoral and popliteal lymph centres. However, the popliteal drainage is specific for the healthy caudal abdominal mammary gland. The inguinal gland can be drained by both inguinofemoral and popliteal lymph centres in both neoplasic and healthy conditions. Regarding the mammary lymphatic communications, this research demonstrated that neoplasic glands present more types of anastomosis (40.9%), than healthy glands (33.33%), and an increase in contralateral anastomosis (50%) compared with healthy ones (33%). Given the data, the mammary neoplasia can change the lymphatic drainage pattern in terms of lymph centres and vascular arborization, thus forming new drainage channels and recruiting a larger number of lymph nodes. Lastly, some comments were made about the severity of a specific neoplasic mammary gland and conditions to be considered before making a decision in terms of the most adequate operative procedure, and suggestions for further investigations.     

The topography of the lymph vessels of mammary glands in female cats

Malignant tumours of the mammary gland in the female cat metastasize, especially through the lymphatic system. However, the anatomical knowledge of this system in cats is not sufficient to develop a reasoned model for the extirpation of these glands in the case of malignant tumours. A study of the topography of the collector vessels in 50 female cats was conducted by indirect injection in vivo of India ink inside the mammary parenchyma. All the lymph nodes were controlled by microscopic examination and lymph vessels were examined after clearing. The success rate of the colouration of the lymph vessels was 76.4%. Clearing showed several principal routes of drainage, different for each gland. Contrary to the presentation observed in the bitch, no evidence existed in any of the 65 cases of lymphatic plexuses connecting the two mammary glands of each row in the female cat. The result of this study is in favour of the development of a new model for the surgical extirpation of mammary tumours in cats.     

Radiographic lymphangiographyin the dog using iodized oil

The objective of this study was to develop a clinically applicable technique to visualize the medial retropharyngeal, superficial cervical, axillary, superficial inguinal and medial iliac lymph nodes on radiographs. Direct and indirect lymphangiographic methods using iodized oil were repeated for a minimum of five times at eight different locations to enhance the various lymph nodes, using 16 healthy research dogs. Direct lymphangiography, although more invasive than indirect lymphangiography, resulted in uniform contrast uptake by an increased number of nodes and increased enhancement of the lymphatic vasculature, and is recommended for imaging the medial iliac and superficial cervical lymph nodes. Side effects were more frequent after indirect lymphangiography (10/20 injection sites) than after direct lymphangiography (3/16 injection sites). The small size of afferent lymphatic vessels did not allow use of direct lymphangiography for the medial retropharyngeal, axillary and superficial inguinal lymph nodes; however, indirect techniques allowed adequate visualization of these nodes.     

Topographie des Collecteurs Lymphatiques Mammaires de la Chienne

The topography of the lymph drainage was examined by in vivo injections of india ink into the mammary parenchyma of 73 female dogs. Only one gland was injected at a time on each side. Only the cranial abdominal mammary gland had direct drainage to the axillary as well as to the superficial inguinal nodes. The principal routes of drainage differ for each gland. The glands on each side are completely independent as regards their lymph drainage. The cranial thoracic mammary glands on each side had their own collecting duct which led to the sternal lymph nodes. The results of this study suggest to develop a new model for the surgical extirpation of mammary tumors in the bitch.     

Frequency of an accessory popliteal efferent lymphatic pathway in dogs

Staging and therapeutic planning for dogs with malignant disease in the popliteal lymph node are based on the expected patterns of lymphatic drainage from the lymph node. The medial iliac lymph nodes are known to receive efferent lymph from the popliteal lymph node; however, an accessory popliteal efferent pathway with direct connection to the sacral lymph nodes has also been less frequently reported. The primary objective of this prospective, anatomic study was to describe the frequency of various patterns of lymphatic drainage of the popliteal lymph node. With informed client consent, 50 adult dogs with no known disease of the lymphatic system underwent computed tomographic lymphography after ultrasound‐guided, percutaneous injection of 350 mg/ml iohexol into a popliteal lymph node. In all 50 dogs, the popliteal lymph node drained directly to the ipsilateral medial iliac lymph node through multiple lymphatic vessels that coursed along the medial thigh. In 26% (13/50) of dogs, efferent vessels also drained from the popliteal lymph node directly to the internal iliac and/or sacral lymph nodes, coursing laterally through the gluteal region and passing over the dorsal aspect of the pelvis. Lymphatic connections between the right and left medial iliac and right and left internal iliac lymph nodes were found. Based on our findings, the internal iliac and sacral lymph nodes should be considered when staging or planning therapy for dogs with malignant disease in the popliteal lymph node.     

FEASIBILITY OF CONTRAST‐ENHANCED ULTRASOUND‐GUIDED BIOPSY OF SENTINEL LYMPH NODES IN DOGS

Our goal was to develop and validate a technique to identify the sentinel lymph nodes of the mammary glands of healthy dogs with contrast‐enhanced ultrasound, and evaluate the feasibility of obtaining representative samples of a sentinel lymph node under ultrasound guidance using a new biopsy device. Three healthy intact female adult hounds were anesthetized and each received an injection of octafluoropropane‐filled lipid microspheres and a separate subcutaneous injection of methylene blue dye around a mammary gland. Ultrasound was then used to follow the contrast agent through the lymphatic channel to the sentinel lymph node. Lymph node biopsy was performed under ultrasound guidance, followed by an excisional biopsy of the lymph nodes and a regional mastectomy procedure. Excised tissues were submitted for histopathologic examination and evaluated as to whether they were representative of the node. The ultrasound contrast agent was easily visualized with ultrasound leading up to the sentinel lymph nodes. Eight normal lymph nodes (two inguinal, one axillary in two dogs; two inguinal in one dog) were identified and biopsied. Lymphoid tissue was obtained from all biopsy specimens. Samples from four of eight lymph nodes contained both cortical and medullary lymphoid tissue. Contrast‐enhanced ultrasound can be successfully used to image and guide minimally invasive biopsy of the normal sentinel lymph nodes draining the mammary glands in healthy dogs. Further work is needed to evaluate whether this technique may be applicable in patients with breast cancer or other conditions warranting evaluation of sentinel lymph nodes in animals.     

Lymphocytes from one side of the bovine mammary gland migrate to the contra lateral gland and lymph node tissue

The four quarters of bovine mammary glands are completely separated and two quarters on each side (right or left) are connected to ipsi lateral supra mammary lymph nodes. It is not clear whether cells infused into the cistern of the mammary gland are capable of migrating to lymph nodes or the general circulation. To examine cell migration, a prescapular lymph node was removed from each of two lactating and three non-lactating dairy cows, and isolated lymphocytes were stained with Hoechst 33342. Autologous stained cells were infused into the mammary gland and then activated by intramammary infusion of zymosan-stimulated serum (source of C5a). After 17 h, Escherichia coli J5 bacterin was infused into the contra lateral mammary gland to mimic infection. After 43 h cows were euthanized and tissue samples (mammary quarters, right and left supra mammary, mesenteric, ileocecal and prescapular lymph nodes, liver and spleen) were collected for microscopic examination as well as flow cytometric analysis. Hoechst stained cells were detected not only in infused quarters, but also in contra lateral quarters as well as in both supra mammary lymph nodes. This indicates that cells infused into the mammary gland migrate to contra lateral tissues and supra mammary lymph nodes.     

Quantification of the effect of various patient and image factors on ultrasonographic detection of select canine abdominal organs.

We assessed factors that affected ultrasonographic visualization of the pylorus, duodenal papilla, pancreas, adrenal glands, and jejunal and medial iliac lymph nodes in the dog. An abdominal ultrasonographic examination was performed on 100 canine patients, equally divided between two facilities. The pylorus was visible in 64% of the dogs, the major duodenal papilla in 42%, the left pancreatic lobe in 56%, the body of the pancreas in 60%, the right pancreatic lobe in 87%, the left adrenal gland in 91%, the right adrenal gland in 86%, the medial iliac lymph nodes in 54%, and the jejunal lymph nodes in 51%. The parameters that negatively influenced the visibility of these organs were the presence of air or food in the gastrointestinal tract (pancreas, duodenal papilla), age (lymph nodes), and body weight (pancreas, duodenal papilla). The parameters that positively influenced their visibility were the presence of air or food in the gastrointestinal tract (lymph nodes), body weight (lymph nodes), body condition score (right adrenal gland), and inherent image quality (left pancreatic lobe). There was a significant difference between the two institutes for the visualization of the pylorus, pancreas, and lymph nodes, which was probably related to different body positions used for scanning in each institution.     

Ultrasonography of the medial iliac lymph nodes in the dog

Sixty-one medial iliac lymph nodes of 38 different dogs (eight with adenocarcinoma of the apocrine glands of the anal sac, 13 with multicentric lymphoma, six with multicentric lymphoma but in clinical remission, and 11 control dogs) were evaluated to assess the ability of ultrasound to identify and interrogate these lymph nodes across the different groups and to differentiate these groups using different sonographic parameters. Ultrasound proved to be useful to assess canine medial iliac lymph nodes. An increase in size or number of detected lymph nodes or finding rounder or heterogeneous lymph nodes could differentiate lymph nodes of dogs of the control group from lymph nodes of dogs with lymphoma or an adenocarcinoma of the apocrine glands of the anal sac. Subcategories of malignancy could not be differentiated. More studies need to be performed, both with patients with reactive lymph nodes and also focusing on other canine superficial lymph nodes, before generalizing the results of this study to other areas or diseases.     

Mammary lipid-rich carcinoma with extensive amyloid deposition in a dog

A 6-year-old female Labrador retriever presented with a mass in the right mammary gland, and swollen right inguinal and axillary lymph nodes. Fine needle aspiration biopsy suggested a malignant lipid-producing tumor, such as liposarcoma. Histopathologically, the neoplasms were solid, lobulated nests of atypical epithelial cells with a large amount of extracellular deposits of amyloid in both mammary gland and lymph nodes. The proliferating cells contained large cytoplasmic vacuoles, positive for oil red-O. These cells were immunopositive for cytokeratin (AE1/AE3) and β-casein and negative for SMA. The amyloid deposits were immunopositive for β-casein. These findings suggested that the proliferating cells secreted β-casein forming amyloid deposits. This is the first report of mammary lipid-rich carcinoma with extensive amyloid deposition derived from β-casein.     

Lymph Drainage from the Ovine Tonsils: An Anatomical Study of the Tonsillar Lymph Vessels

Although the tonsils of sheep have gained much attention during the last decade, only few data are available on their lymph vessel architecture. Tonsillar lymph vessels are immunologically important as they form the efferent routes for locally activated immune cells to reach the draining lymph nodes. To gain insight into the tonsillar lymph drainage in the sheep, Indian ink and a casting polymer were injected into the interstitium of the five tonsils present in the heads of slaughtered sheep. This enabled us to determine the draining lymph node and to examine the microscopic organization of lymph vessels using light and scanning electron microscopy. No lymph vessels were observed within the tonsillar lymphoid follicles. The corrosion casts demonstrated that the lymphoid follicles are surrounded by numerous sacculated lymph sinuses that drain into a dense interfollicular lymph vessel network. From here, the lymph flows into single small lymph vessels that in turn drain into larger lymph vessels extending towards the medial retropharyngeal lymph node. The presented results can be valuable for immunological studies, for example during oral or intranasal vaccine development.     

Effect of milk stasis on Brucella abortus infection of the mammary gland in goats

To compare the effects of milk stasis and milk flow on Brucella abortus infection of the mammary gland under the same systemic conditions, primiparous goats (n = 5) were inoculated IV with B abortus on the day of parturition, and suckling by their neonates was restricted to one mammary gland. Goats were euthanatized and necropsied at 3 weeks after inoculation, and milk, mammary glands, and supramammary lymph nodes were evaluated by bacteriologic, histologic, and immunoenzymatic staining techniques. Nonnursed mammary glands had high titers of brucellae in milk, moderate interstitial mastitis, and brucellar antigen in macrophages located primarily in alveolar and ductal lumina. Brucellae often filled the macrophage cytoplasm. In contrast, nursed mammary glands had fewer brucellae in milk, minimal inflammatory changes, and no detectable brucellar antigen in histologic sections. Hyperplastic changes were only seen in supramammary lymph nodes draining nonnursed mammary glands; these contained more brucellae than lymph nodes draining nursed mammary glands. These studies show that milk stasis may be the sole cause of increased susceptibility of nonnursed mammary glands to B abortus infection.     

Prognostic value of regional lymph node status in canine mammary carcinomas

In this study, we have determined the prognostic value of the presence of the micrometastases and metastases greater than 2 mm in the regional lymph nodes for bitches with mammary carcinomas. The study involved 51 dogs diagnosed with a single malignant epithelial tumour in the 4th or 5th mammary gland. All animals underwent regional mastectomy; the 4th and 5th mammary glands were removed together with the inguinal lymph node. The lymph nodes were examined immunohistochemically using the anti-cytokeratin antibody, clone AE1/AE3. The bitches were followed up every 6 months for 2 years after surgery to determine the disease-free survival (DFS) and overall survival (OS). The Kaplan-Meier analysis showed a statistically significant difference in DFS and OS only between the group of bitches without metastases and the group with lymph node metastases greater than 2 mm. No significant differences between these two groups versus bitches with lymph node micrometastases were found.     

Specific antibody-containing cells in the mammary gland of non-lactating sheep after intraperitoneal and intramammary immunisation

Ewes were immunised intraperitoneally with ovalbumin and Brucella abortus in Freund's complete adjuvant, followed seven days later by intramammary immunisation in which ovalbumin was presented to one mammary gland and Brucella abortus to the other. Mammary tissue taken after a further seven days contained more antigen-specific plasma cells than ewes given intraperitoneal or intramammary immunisation alone. These cells were found predominantly in the specifically immunised gland and only a few were found in the contralateral gland. Most of these cells were of the IgG1 isotype. There was also an increase in the total number of IgG1- and IgG2-containing cells in mammary gland tissues of these ewes, indicating a non-specific response to immunisation. Following either intraperitoneal or intramammary immunisation there was also a significant increase in the number of antigen-specific IgA cells in the lamina propria of the jejunum. The gut response following intramammary immunisation alone was abrogated by chronic drainage of intestinal lymph but not mammary lymph. This suggests that antigen may relocate from the mammary gland to the intestine where an IgA response is generated from gut associated lymphoid tissue. These data provide evidence for interaction between the gut and mammary gland of sheep in response to antigen.