Lymphatic malformation causing intractable chylorrhagia

Lymphatic malformation is a developmental error usually noticed at birth or in early childhood. Lesions of the upper leg and lower trunk are the most difficult to remove, because they are often the largest ones encountered and also because they tend to extend proximally into the retroperitoneal tissues. Chyle reflux, usually associated with lymphedema of the extremity, has not been reported to be caused by lymphatic malformation. We report a case of intrapelvic retroperitoneal lymphatic malformation with an extension of gluteal-thigh soft-tissue involvement causing intractable chylorrhagia. The tumor was subtotally excised, and the defect was closed by a distally based, peninsular latissimus dorsi myocutaneous flap. The flap served both as a filling material and as a "bridge" between the residual tumor, including abnormal lymphatics, and normal lymph flow.     

Aberrant Lymphatic Endothelial Progenitors in Lymphatic Malformation Development

Lymphatic malformations (LMs) are vascular anomalies thought to arise from dysregulated lymphangiogenesis. These lesions impose a significant burden of disease on affected individuals. LM pathobiology is poorly understood, hindering the development of effective treatments. In the present studies, immunostaining of LM tissues revealed that endothelial cells lining aberrant lymphatic vessels and cells in the surrounding stroma expressed the stem cell marker, CD133, and the lymphatic endothelial protein, podoplanin. Isolated patient-derived CD133+ LM cells expressed stem cell genes (NANOG, Oct4), circulating endothelial cell precursor proteins (CD90, CD146, c-Kit, VEGFR-2), and lymphatic endothelial proteins (podoplanin, VEGFR-3). Consistent with a progenitor cell identity, CD133+ LM cells were multipotent and could be differentiated into fat, bone, smooth muscle, and lymphatic endothelial cells in vitro. CD133+ cells were compared to CD133− cells isolated from LM fluids. CD133− LM cells had lower expression of stem cell genes, but expressed circulating endothelial precursor proteins and high levels of lymphatic endothelial proteins, VE-cadherin, CD31, podoplanin, VEGFR-3 and Prox1. CD133− LM cells were not multipotent, consistent with a differentiated lymphatic endothelial cell phenotype. In a mouse xenograft model, CD133+ LM cells differentiated into lymphatic endothelial cells that formed irregularly dilated lymphatic channels, phenocopying human LMs. In vivo, CD133+ LM cells acquired expression of differentiated lymphatic endothelial cell proteins, podoplanin, LYVE1, Prox1, and VEGFR-3, comparable to expression found in LM patient tissues. Taken together, these data identify a novel LM progenitor cell population that differentiates to form the abnormal lymphatic structures characteristic of these lesions, recapitulating the human LM phenotype. This LM progenitor cell population may contribute to the clinically refractory behavior of LMs.     

Lymphatic malformations

Lymphatic malformations are rare forms of vascular anomalies. They are most frequently diagnosed at birth and most often occur in the head and neck area. Their treatment continues to be challenging, and treatment methods continue to evolve. In this article, the embryology of the lymphatic system is reviewed, and the classification of lymphatic malformations and their natural history and treatment are discussed.     

Congenital malformation in twins.

Data from the population-based Metropolitan Atlanta Congenital Defects Program (MACDP) show that the overall rate of malformed infants, as well as the incidence of several specific defects, is higher for twins than for singletons. This elevated risk appears limited to same sex twins and, hence, is probably related to monozygosity. In addition to an 18-fold increase in risk of fetal death compared to singletons, twins have almost a 50% greater likelihood of congenital malformation.     

Lymphatic vasculature development

Although the process of blood vasculature formation has been well documented, little is known about lymphatic vasculature development, despite its importance in normal and pathological conditions. The lack of specific lymphatic markers has hampered progress in this field. However, the recent identification of genes that participate in the formation of the lymphatic vasculature denotes the beginning of a new era in which better diagnoses and therapeutic treatment(s) of lymphatic disorders could become a reachable goal.     

Lymphatic network and lymphangiogenesis in the gastric wall.

A family of growth factors highly specific for endothelial cells was identified more than 10 years ago, in which the receptor of vascular endothelial growth factor C (VEGFR-3) is implicated in the regulation of lymphatic development and regeneration. Comparative studies on the lymphatic network and lymphangiogenesis have been done mainly using combined 5'-nucleotidase (5'-Nase) enzyme and VEGFR-3 immunohistochemical approaches in adult and fetal gastric walls. Developing lymphatic networks represented fewer blind ends and branches than mature networks in whole-mount preparations. Many circular lymphatic-like structures exhibited VEGFR-3 expression and weak 5'-Nase activity in the early embryonic stage, showing visible morphological properties in the lymphatic endothelium. These newly formed lymphatics showed an obvious accumulation in the submucosa and serosa and a variation in the intensity of VEGFR-3 binding to endothelial cells among samples. A reaction product for anti-VEGFR-3 was found on the luminal surface of endothelial cells and on the membrane of some organelles and intraluminal lymphocytes. These findings indicate that an active proliferating feature of the clustered developing lymphatics may create a favorable environment for their sprouting and growth, which may serve as a functional requirement for lymph drainage in the region.     

Dislocation and/or congenital malformation of the shoulder joint. Observations on a Mediaeval skeleton from Denmark

The purpose of this paper is to present a Mediaeval skeleton of an approximately 16 year old boy, which was excavated at a Danish cemetery containing ca. 150 graves. The skeleton reveals several pathologic changes, probably due to congenital malformation. The most intriguing find is seen at both scapulae, and the changes are bilateral symmetric. Both the glenoid cavities are placed posterior but at the normal height of the bone. The joints are almost perpendicular to their normal direction. The size of the glenoid cavities is normal and the shape is rather flat in accordance to the development stage of the skeleton, where the epiphysis of the rim has not yet appeared to form the gently concave fossa as normally seen in adults. Both the surface and the borderlines of the glenoid cavities are, however, more irregular than normally at that age. The position of the joints may be caused by dislocation and/or congenital malformation which is discussed. Due to the shape of the cavities, to the symmetric bilaterality, and to the minor congenital malformations, it is primarily believed to be caused by congenital malformation. Probably the young man was not much affected by the malformation of the shoulder joints, which is indicated by the normal form and size of the humeri and the well-developed muscle attachments of the bones. The claviculae seem shorter and more twisted than normal, which may be caused by a twisting of the scapulae. So the glenoid cavities may have pointed almost in the normal direction in spite of the malformation. Other minor malformations are spina bifida of the atlas and the 5. lumbar vertebra, multiple minor changes of the joints of both feet and malformations of one metatarsal bone in both feet. Agenesi of the praemolars is also seen. Although our study of the literature, we have not succeeded in correlation our finds with any known congenital syndrome, and as far as we know no similar case has been described in clinical observation or in skeletal finds.     

Loss of HB-EGF in smooth muscle or endothelial cell lineages causes heart malformation

Epidermal growth factor (EGF) and ErbB family molecules play a role in heart development and function. To investigate the role of EGF family member, heparin-binding EGF-like growth factor (HB-EGF) in heart development, smooth muscle and endothelial cell lineage-specific HB-EGF knockout mice were generated using the Cre/loxP system in combination with the SM22alpha or TIE2 promoter. HB-EGF knockout mice displayed enlarged heart valves, and over half of these mice died during the first postnatal week, while survivors showed cardiac hypertrophy. These results suggest that expression of HB-EGF in smooth muscle and/or endothelial cell lineages is essential for proper heart development and function in mice.     

Lymphatic vessels in the developing diaphragm of the rat.

Diaphragms of fetal, neonatal and young albino rats have been observed both under light and electron microscopes to examine the presence and distribution of lymphatic vessels and their morphological features. In fetal diaphragms of between 18 and 22 days of gestation, no normal lymphatic vessels can be seen; only after birth, specifically in neonatal and 2-day-old rats, small lymphatic vessels appear; they are in close proximity to the blood vessels in the inner areas of the muscle. As the rats get older, lymphatic vessels are also observed in the subserosa where an abundant connective tissue is present. The fine structure of diaphragmatic lymphatic vessels is different at different ages. In neonatal rats of up to 2 days, the endothelial wall is very thin and often holed. The relationships between contiguous endothelial cells are characterized by simple end-to-end or overlapping structures. The basement membrane is virtually absent. Within the first week of life, the endothelial wall becomes more complex; along the wall, complex interdigitations between two contiguous endothelial cells often touch. A discontinuous basement membrane and collagen and elastic fibers surround the vessels. In the older rats (from 14 to 25 to 140 days), next to the complex interdigitations which characterize the junction between two contiguous endothelial cells, cellular flaps interdigitate forming a channel which opens out either to the exterior or the interior of the vessel. Dense bundles of elastic and collagen fibers are closely apposed to the endothelial wall.