Fluorescence microlymphography.

Microneedles, 0.2 mm o.d., were connected to a microsyringe and mounted on a micromanipulator. Under microscopic control, 0.01 ml of a 25% solution of FITC-labeled dextran-40 or dextran-150 were injected into the subepidermis at the big toe near the nailfold or in the medial ankle region. Fluorescence intravital microscopy revealed a network of lymphatic microvessels. The comparison with recent anatomic studies reveals that the reticular network visualized by FITC-dextran corresponds to the network in the stratum papillare. In 20 healthy subjects lymphatic capillaries were detected in a restricted area on the lateral aspect of the big toe. In 10 patients with primary lymphedema, the dye expanded to almost the entire dorsal skin surface of the big toe. In two cases, enlarged and tortuous microvessels of pathologic shape were observed. Fluorescence microlymphography is a simple and nearly atraumatic approach for depicting the intravital anatomy of human skin lymphatic capillaries.