Lymphatic research and biology
-
Review Case Reports
Growth plate uptake of Tc-99m-phytate on lymphoscintigraphy images.
We report two pediatric cases with the history of lower extremity edema who were referred to the nuclear medicine department for lower limb lymphoscintigraphy as lymphedema workup. Subcutaneous injection of Tc-99m phytate in the interdigital webs was used for both patients, followed by early and delayed whole body lymphoscintigraphy imaging. ⋯ This biodistribution could interfere with popliteal lymph node visualization and should always be taken into account in lymphoscintigraphy of pediatric patients. We also review the medical literature regarding biodistribution Tc-99m phytate after interstitial injections.
-
Axillary surgery for breast cancer may be followed, months to years later, by chronic arm lymphedema. A simple 'stopcock' mechanism (reduced lymph drainage from the entire limb through surviving lymphatics) does not explain many clinical aspects, including the delayed onset and selective sparing of some regions, e.g., hand. Quantitative lymphoscintigraphy reveals that lymph drainage is slowed in the subcutis, where most of the edema lies, and in the subfascial muscle compartment, which normally has much higher lymph flows than the subcutis. ⋯ Further evidence for predisposing abnormalities is the finding of lymphatic abnormalities in the contralateral (nonswollen) arm in women with established BCRL. Such predisposing factors could explain why some women develop BCRL after sentinel node biopsy, whereas others do not after clearance surgery. Future research must focus on prospective observations made from before surgery until BCRL develops.
-
Lymphedema, defined as the abnormal accumulation of protein-rich fluid in soft tissues, results from the dysfunction of lymphatic system, an imbalance between lymph formation and its absorption into the initial lymphatics. Primary lymphedema occurs rarely on idiopathic or developmental abnormalities, especially hypoplasia or aplasia of lymphatics. Secondary lymphedema commonly develops when lymph transport is impaired due to lymphatic damage or resection of lymph nodes in surgery, infection, and radiation. ⋯ FOXC2 may have a key role in regulating interactions between LECs and smooth muscle cells, and in the morphogenesis of lymphatic valves. Reduced VEGFR-3 tyrosine kinase activity and subsequent failure in transducing sufficient physiological VEGF-C/-D signals may affect LEC function and structure in the intercellular junctions and peri-lymphatic components. Identification of genetic markers in humans and animal models would facilitate the management of environmental factors influencing the expression and severity of lymphedema, and provide a basis for developing novel targeted therapies for the disease.