[Morphology and histochemistry of lymphatic vessels of the upper aerodigestive tract: a clinically oriented study].

BACKGROUND

Exact knowledge of lymphatic morphology and histochemistry is required to understand the clinical importance of the lymphatic system of the upper aerodigestive tract. Publications in this field are rare.

METHODS

Light and electronmicroscopic examinations were carried out on lymphatics of the upper aerodigestive tract. Enzyme, immune and histochemical investigations were also performed on 764 tissue specimens from this region.

RESULTS

The discontinuous basement membrane surrounding the initial lymphatic contains laminin, type IV collagen, and fibronectin and is usually continued by a fibrillar elastic apparatus that is less developed than dermal lymphatics. 5'-nucleotidase, adenylatcyclase, and guanylatcyclase activity in lymphatics is not as high as it is in blood capillaries. The endothelium of collecting lymphatics contains high concentrations of factor VIII associated antigen, while it is found in the endothelium of initial lymphatics only in small amounts or not at all. Histochemical studies of the endothelium of lymphatics show a positive lectine binding reaction for UEA I, PNA, DBA, GS I, MPA, and RCA I.

CONCLUSIONS

The histochemical results obtained allow easy differentiation of lymphatics and blood capillaries. The vessel type differentiation is relevant for the examination of organ-related lymphatic systems, to determine whether tumor cell nests are located in lymphatics, blood capillaries, or artificial tissue gaps.