Head and neck lymphatic tumors and bony abnormalities: a clinical and molecular review.

Lymphatic malformations and lymphatic-derived tumors commonly involve the head and neck, where they may be associated with bony abnormalities and other systemic symptoms. The reasons for the association between these disorders and local skeletal changes are largely unknown, but such changes may cause significant disease-related morbidity. Ongoing work in molecular and developmental biology is beginning to uncover potential reasons for the bony abnormalities found in head and neck lymphatic disease; this article summarizes current knowledge on possible mechanisms underlying this association.

Increased vascular endothelial growth factor-C expression is insufficient to induce lymphatic metastasis in human soft-tissue sarcomas.

PURPOSE: Unlike carcinomas, soft-tissue sarcoma (STS) rarely exhibit lymphatic spread. Consequently, we examined expression and function of vascular endothelial growth factor (VEGF)-C and STS-associated lymphatic vessel density (LVD) components of this process. EXPERIMENTAL DESIGN: VEGF-C and VEGF-A mRNA and VEGF-C protein expression were evaluated in STS, STS cell lines, and breast cancers (reverse transcription-PCR, quantitative reverse transcription-PCR, and ELISA). STS cell conditioned medium after VEGF-C knockdown was examined for endothelial cell proliferation and migration effects (MTS and migration assays). Paraffin-embedded human lymph node-negative and lymph node-positive STS and lymph node-negative and lymph node-positive breast cancers were examined for VEGF-C, D2-40, and CD31 expression (immunohistochemistry). LVD differences were analyzed by Wilcoxon rank-sum tests. RESULTS: STS and breast cancer VEGF-C expression was comparable and higher than normal tissue levels. STS cells secreted functional VEGF-C: STS conditioned medium induced lymphatic endothelial cell proliferation and migration, which was abrogated by STS cell VEGF-C knockdown. STS and breast cancer intratumoral LVD was similar. STS peritumoral LVD (PT-LVD) was reduced versus breast cancer PT-LVD (P < 0.001). Significantly higher PT-LVD was observed in lymph node-positive versus lymph node-negative STS; lymphatic spreading STS subtypes also had higher LVD. STS VEGF-C expression and PT-LVD lacked correlation, and many lymph node-negative STS had high PT-LVD, suggesting complexity in this metastatic process. CONCLUSIONS: Compared with breast cancers, STS exhibited lower PT-LVD independent of VEGF-C expression, which may underlie STS lymph node metastasis rarity. Moreover, lymphatic vessels appear necessary but not sufficient to sustain STS lymphatic spread. Examining STS "nonlymphatic" dissemination may help elucidate mechanisms of lymphatic spread, insights critically important to cancer metastasis control.

Identification of lymphatic endothelium in pediatric vascular tumors and malformations.

The distinction between lymphatic and other vascular vessels on microscopic sections is a challenging task. D2-40, a novel antibody, has been reported to be selective for lymphatic endothelium. We studied the specificity and sensitivity of D2-40 in pediatric vascular tumors and malformations. Fourteen lymphatic and 11 vascular lesions were randomly selected and stained with D2-40 and CD31 antibodies. The lymphatic lesions included 6 lymphatic malformations, 5 cystic hygromas (macrocystic lymphatic malformation), 2 lymphovenous malformations, and 1 lymphangioma, and the vascular lesions comprised 3 infantile hemangiomas, 3 Kaposiform hemangioendotheliomas, 2 tufted angiomas, 1 pyogenic granuloma, 1 arteriovenous, and 1 venulocapillary malformations. The staining patterns of the vascular channels were compared. In all lesions D2-40 labeled only the endothelium of thin-walled vascular channels morphologically consistent with lymphatic vessels (25 of 25). No staining of the vascular lesions (0 of 11) or of arteries and veins (0 of 25) was observed. All lymphatic lesions had D2-40-positive vessels; however, the percentage of vessels that stained varied. Five lymphatic lesions showed more than 75% D2-40-positive channels, 5 lesions had approximately 50%, and 4 cases showed fewer than 25% D2-40-positive channels. There was a tendency of more consistent D2-40 staining of small versus large lymphatic channels. CD31 constantly labeled arteries, veins, capillaries, and lymphatics in all lesions and all endothelial cells in the vascular lesions. D2-40 is a very specific antibody for lymphatic endothelium, with variable sensitivity. CD31 more reliably identifies lymphatic endothelium. Currently, D2-40 appears to be a good marker to identify lymphatic vessels in pediatric vascular tumors and malformations.