A HISTOLOGICAL STUDY OF HYALINE DEPOSITS IN LARYNGEAL, AURAL, AND NASAL POLYPS AND THEIR DIFFERENTIATION FROM AMYLOID.

Sections of hyalinized laryngeal polyps stained with haematoxylin and eosin or Congo red can easily be confused with localized amyloid of the larynx. Several histological methods were applied to 61 specimens containing hyaline deposits or hyalinized tissues which included 36 laryngeal polyps. The results were compared with seven cases of localized amyloidosis of the upper respiratory tract and four cases of secondary amyloidosis. The hyaline deposits gave a pattern of results which were different from amyloid. They showed no metachromasia, low affinity for Congo red, weak birefringence in an unstained state, no birefringence if stained with Congo red, weak or negative fluorescence if stained with Thioflavin T, low resistance to pepsin digestion, positive phosphotungstic acid haematoxylin staining areas, and a high affinity for the picric acid component of van Gieson stain. Hyalinized collagen closely resembles amyloid, but it can be excluded by a van Gieson stain. No evidence of amyloid formation was found in areas of hyaline deposits in the larynx. This supports the view that localized amyloidosis of the larynx and hyalinized laryngeal polyps are different pathological entities.