Pathological steps of cancer-related lymphedema: histological changes in the collecting lymphatic vessels after lymphadenectomy.
BACKGROUND
To date, an electron microscopy study of the collecting lymphatic vessels has not been conducted to examine the early stages of lymphedema. However, such histological studies could be useful for elucidating the mechanism of lymphedema onset. The aim of this study was to clarify the changes occurring in collecting lymphatic vessels after lymphadenectomy.


METHODS
The study was conducted on 114 specimens from 37 patients who developed lymphedema of the lower limbs after receiving surgical treatment for gynecologic cancers and who consulted the University of Tokyo Hospital and affiliated hospitals from April 2009 to March 2011. Lymphatic vessels that were not needed for lymphatico venous anastomosis surgery were trimmed and subsequently examined using electron microscopy and light microscopy.


RESULTS
Based on macroscopic findings, the histochemical changes in the collecting lymphatic vessels were defined as follows: normal, ectasis, contraction, and sclerosis type (NECST). In the ectasis type, an increase in endolymphatic pressure was accompanied by a flattening of the lymphatic vessel endothelial cells. In the contraction type, smooth muscle cells were transformed into synthetic cells and promoted the growth of collagen fibers. In the sclerosis type, fibrous elements accounted for the majority of the components, the lymphatic vessels lost their transport and concentrating abilities, and the lumen was either narrowed or completely obstructed.


CONCLUSIONS
The increase in pressure inside the collecting lymphatic vessels after lymphadenectomy was accompanied by histological changes that began before the onset of lymphedema.
Department of Plastic and Reconstructive Surgery, The University of Tokyo, Tokyo, Japan. mihara@keiseigeka.name
Makoto
M
Mihara
Hisako
H
Hara
Yohei
Y
Hayashi
Mitsunaga
M
Narushima
Takumi
T
Yamamoto
Takeshi
T
Todokoro
Takuya
T
Iida
Naoya
N
Sawamoto
Jun
J
Araki
Kazuki
K
Kikuchi
Noriyuki
N
Murai
Taro
T
Okitsu
Iori
I
Kisu
Isao
I
Koshima
D000328:Adult; D000368:Aged; D003896:Desmosomes / Q000473:pathology / Q000648:ultrastructure; D042783:Endothelial Cells / Q000473:pathology / Q000648:ultrastructure; D005260:Female; D024022:Fibrillar Collagens / Q000648:ultrastructure; D006801:Humans; D008197:Lymph Node Excision; D042601:Lymphatic Vessels / Q000473:pathology*; D008209:Lymphedema / Q000209:etiology* / Q000473:pathology*; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000473:pathology / Q000648:ultrastructure; D009369:Neoplasms / Q000150:complications* / Q000601:surgery
D024022:Fibrillar Collagens