TITLE:
Tumor-Associated Lymphatic and Venous Vessels in Medullary Thyroid Carcinomas
AUTHORS:
Tatsuo Tomita
KEYWORDS:
Blood Vessels, Chromogranin A, Factor 8, Immmunocytochemistry, Lymphatic Vessels, LYVE-1, Medullary Thyroid Carcinoma
JOURNAL NAME:
Open Journal of Pathology,
Vol.5 No.2,
April
13,
2015
ABSTRACT: Objective: Medullary thyroid carcinomas
(MTCs) invade local lymph node through lymphatic vessels and metastasize to
distant organs hematogenously and account for a significant mortality. There
are possibly increased lymphatic and venous vessels, through which the tumor
spreads to lymph nodes and distant organs. Materials and Methods: By
immunocytochemical staining for lymphatic and venous vessels, MTC lesions with
adjacent normal thyroid and both normal and metastatic lymph nodes were studied
for the peritumoral lymphatic and venous vessels, which were morphometrically
compared with those of normal thyroid and lymph nodes. Sixteen cases of MTC
cases with adjacent thyroid tissues and attached lymph nodes were
immunocytochemically stained for lymphatic vessels using lymphatic vessel
hyaluronan receptor (LYVE-1) and venous vessels for factor VIII (F-8). The
immunostained sections of MTC lesions and metastatic lymph nodes were
morphometrically compared for the number and sizes of the vessels with those of
normal thyroid tissues and lymph nodes. Results: Significantly increased
lymphatic vessels and markedly increased blood vessels were identified in many
MTC cases at the peritumoral tissues and metastatic lymph nodes whereas a few
lymphatic vessels and no venous vessels were identified in midst of MTCs. The
irregular peritumoral lymphatic vessels resembled that of immature lymphatic
vessels observed in papillary thyroid carcinomas and increased irregularly,
entrapped venous vessels in peritumoral tissues resembled those observed in
follicular thyroid carcinomas. Conclusion: The significantly increased
lymphatic vessels and markedly increased venous vessels in the peritumoral
thyroid tissue support a propensity of MTCs for providing an easy access of
tumor cells to both lymphatic spread to the regional lymph nodes and venous
spread to distant organs with further tumor spread through metastatic lymph
nodes by moderately increased lymphatic and venous vessels.