Laryngologists must be prepared to alter their surgical planning and treatment approaches because of diagnostic changes that may happen during surgery.

Schwannomas are benign nerve sheath tumors composed of Schwann cells, which normally produce the insulating myelin sheath covering peripheral, cranial and autonomic nerves. Twenty-five to forty-five percent of all schwannomas occur in the head and neck region, but location of such tumors in the larynx is rarely observed. The present report is aimed at describing a clinical case of laryngeal schwannoma, with emphasis on sonographic findings.

Hormone plays an important role in the larynx. Among other substances, vocal folds contain hyaluronic acid, which tissue concentration may vary according to hormone action. Aim: the objective of this study is to analyze hyaluronic acid concentration in the vocal folds during estral and gravidic-puerperal cycles. Study design: Experimental study. Materials and Methods: 40 adult rats were divided into two groups. In the first group we used 20 rats to establish the concentration of hyaluronic acid during the estral cycle and in the second group, 20 animals were submitted to the same procedure but during the gravidic-puerperal cycle. Results: Variations in hyaluronic acid concentration was not observed during the estral cycle. In the gravidic puerperal cycle group, an increase in hyaluronic acid concentration was observed in the puerperal subgroup. Comparing the two groups of estral and gravidic-puerperal cycles, no difference was observed. Conclusions: In comparing all subgroups of estral and gravidic-puerperal cycles, an increase in hyaluronic acid concentration was noticed only in the puerperal phase.

Hyal uronic acid receptor is a glycoprotein of the plasmatic membrane, and the CD44 is its representative, expressed in many cell types where it has the task of cell adhesion. Aim: the goal of the present experimental study is to investigate the possibility of using immunohistochemistry to identify the distribution of hyaluronic acid along the vocal fold. Materials and Methods: We resected the normal vocal folds from a normal 23 year-old male black individual. The slides were analyzed by means of a histomorphometric study, comparing the color intensity in the superficial, middle and deep layers of the lamina propria. In the silanized slides we used immunohistochemistry, and evaluated the slides under light microscopy with 40x magnification, and the color changed to brown when there was a reaction with the receptor for hyaluronic acid. Results: Immunohistochemical findings showed the presence of hyaluronic acid receptors in the epithelium covering the vocal fold, being more concentrated in the central region of the vocal fold. Conclusion: immunohistochemistry, used to assess the distribution of hyaluronic acid receptors in the central portion of the vocal fold, proved it to be present in the vocal fold epithelium and it prevailed in its middle third.