Abstract

Superficial erythematous cutaneous vascular malformations are assumed to be blood vascular in origin, but cutaneous lymphatic malformations can contain blood and appear red. Management may be different and so an accurate diagnosis is important. Cutaneous malformations were investigated through 2D-histology and 3D-whole-mount-histology. Two lesions were clinically considered as port-wine birthmark, and another three lesions as erythematous telangiectasias.The aims were: i) to prove that cutaneous erythematous malformations including telangiectasia can represent a lymphatic phenotype, ii) to determine if lesions represent expanded but otherwise normal or malformed lymphatics, and iii) to determine if the presence of erythrocytes explained the red colour. Microscopy revealed all lesions as lymphatic structures. Port-wine birthmarks proved to be cystic lesions, with non-uniform lymphatic marker expression, and a disconnected lymphatic network suggesting a lymphatic malformation. Erythematous telangiectasias represented expanded but non-malformed lymphatics. Blood within lymphatics appeared to explain the colour. Blood-lymphatic-shunts could be detected in the erythematous telangiectasia.In conclusion, erythematous cutaneous capillary lesions may be lymphatic in origin but clinically indistinguishable from blood vascular malformations. Biopsy is advised for correct phenotyping and management. Erythrocytes are the likely explanation for colour accessing lymphatics through lympho-venous-shunts.