Histologic structure and development of the laryngeal macula flava.

The laryngeal maculae flavae (MF) have been previously described as cellular condensations at the extremities of the vocal cords, but the exact nature and role of the MF are unknown. The purpose of this study is a histomorphological analysis of the nature and development of the MF in human vocal cords, from the beginning of fetal life to adulthood. Eighty-six larynges, from the fetus at 12 weeks of amenorrhea (WA) to adulthood, were collected from autopsies and studied by light microscopy with hematoxylin and eosin, orcein, and Alcian blue staining and pS 100 immunostaining. Our observations allowed us to separate the fetal development of the MF into 4 periods. The first corresponds to the appearance of the posterior MF between 13 and 15 WA. In the second period, the anterior MF appeared between 16 and 18 WA, allowing definition of the intermacular space. Fibrous structures, composed of collagen and elastic fibers, of the MF and intermacular space developed between 20 and 33 WA. The last period, from 33 WA to birth, corresponded to a maturation of these structures. In adults, the histologic structure of the MF presented a concentric peripheral fibrous layer associated with a central cellular component. Structural analysis of the MF concludes in favor of the chondroid nature of the macular cell. These observations bring into question the current knowledge on the MF. From these observations, the role of the MF in the developing vocal cord is discussed.