The anatomy of fetal peripheral lymphatic vessels in the head-and-neck region: an immunohistochemical study.
Using D2-40 immunohistochemistry, we assessed the distribution of peripheral lymphatic vessels (LVs) in the head-and-neck region of four midterm fetuses without nuchal edema, two of 10 weeks and two of 15 weeks' gestation. We observed abundant LVs in the subcutaneous layer, especially in and along the facial muscles. In the occipital region, only a few LVs were identified perforating the back muscles. The parotid and thyroid glands were surrounded by LVs, but the sublingual and submandibular glands were not. The numbers of submucosal LVs increased from 10 to 15 weeks' gestation in all of the nasal, oral, pharyngeal, and laryngeal cavities, but not in the palate. The laryngeal submucosa had an extremely high density of LVs. In contrast, we found few LVs along bone and cartilage except for those of the mandible as well as along the pharyngotympanic tube, middle ear, tooth germ, and the cranial nerves and ganglia. Some of these results suggested that cerebrospinal fluid outflow to the head LVs commences after 15 weeks' gestation. The subcutaneous LVs of the head appear to grow from the neck side, whereas initial submucosal LVs likely develop in situ because no communication was evident with other sites during early developmental stages. In addition, CD68-positive macrophages did not accompany the developing LVs.
Department of Neurology, Wonkwang University School of Medicine, Institute of Wonkwang Medical Science, Jeonbuk Regional Cardiocerebrovascular Disease Center, Iksan, Korea. neurology@wonkwang.ac.kr
Kwang Ho
KH
Cho
Jin Sung
JS
Cheong
Yeon Soo
YS
Ha
Baik Hwan
BH
Cho
Gen
G
Murakami
Yukio
Y
Katori
D005333:Fetus / Q000033:anatomy & histology* / Q000166:cytology; D006257:Head; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D042601:Lymphatic Vessels / Q000033:anatomy & histology / Q000166:cytology / Q000196:embryology*; D009333:Neck