Histopathologic Investigations of the Unphonated Human Child Vocal Fold Mucosa

Objectives Vocal fold stellate cells (VFSCs) in the maculae flavae (MFe) located at both ends of the vocal fold mucosa are inferred to be involved in the metabolism of extracellular matrices. MFe are also considered to be an important structure in the growth and development of the human vocal fold mucosa. Tension caused by phonation (vocal fold vibration) is hypothesized to stimulate VFSCs to accelerate production of extracellular matrices. Human child vocal fold mucosae unphonated since birth were investigated histologically. Study Design Histologic analysis of human child vocal fold mucosa. Methods Vocal fold mucosae, which have remained unphonated since birth, of two children (7 and 12 years old) with cerebral palsy were investigated by light and electron microscopy and compared with normal subjects. Results Vocal fold mucosae and MFe were hypoplastic and rudimentary and did not have a vocal ligament, Reinke’s space, or the layered structure. The lamina propria appeared as a uniform structure. Some VFSCs in the MFe showed degeneration and not many vesicles were present at the periphery of the cytoplasm. The VFSCs synthesized fewer extracellular matrices, such as fibrous protein and glycosaminoglycan. The VFSCs appeared to have decreased activity. Conclusion Vocal fold vibration (phonation) after birth is an important factor in the growth and development of the human vocal fold mucosa.