Earlier investigation did not show any clear distinctive pathological features that differentiate vocal polyps from vocal nodules. The light microscopic distinctive features between the two lesions point in the direction of a more pronounced epithelial reaction and a more fibrous stromal change in vocal nodules. In the present study, 19 vocal polyps and 11 vocal nodules were subjected to ultrastructural examination aiming at finding distinctive features that may be pathognomic for each of these clinically distinct entities. The study was carried out by EM Philips 400 T. The results demonstrate that nodules showed epithelial changes in the form of gaping of the intercellular junctions and absence of the basal lamina in parts. These changes are less apparent in polyps, whereas the stromal changes are more pronounced and varied. The significance of these results and their interpretation are discussed.

Light and electron microscopic studies of biopsy specimens taken from five patients with pityriasis rosea revealed the most conspicuous finding to be the presence of dyskeratotic cells within the epidermis. Ultrastructurally, these cells contained an aggregation of tonofilaments, intracytoplasmic desmosomes, many vacuoles, and viral-like particles. It is assumed that pityriasis rosea is caused by a virus to which these changes are related.

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