Retraction pocket of the pars tensa. Surgical and histological studies.
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Retraction of the pars tensa can result in erosion of the ossicles leading to hearing loss and eventually cholesteatoma, different types of treatment have been described for retraction pocket and the pathology has a little attention, so the aim of this work was to assess the outcome following simple excision and ventilation tube insertion of retraction pocket of the pars tensa and to study the histopathological and ultrastructural changes to the excised parts. This study was conducted on 32 patients with unilateral retraction pocket in pars tensa. The ear drums were graded according to sade et al., 1982 classification. There were 12 cases with grade 1, 13 with grade II, and 7 with grade III. Grade V was excluded from this study, all cases ware subjected to excision of retracted part with grommet tube insertion. Eleven cases with grade I and 10 cases with grade II showed complete normal healing. One case from grade I showed pocket recurrence, the remainder 3 cases of grade II showed packet recurrence, in 2 cases and persistent perforation in one case, while all case of grade III showed pocket recurrence, in 4 cases and persistent perforation in 3 cases. The flailed cased in this study have undergone a second surgery with tympanoplasty by tragal cartilage pericondrium graft. There was curling of the surface epithelium of the tympanic membrane. Various degrees of papillay ingrowth towards the lamina propria were seen. There was much greater amount of keratin on the outer surface. The squamous epithelium appeared to be thickened because of the presence of a large number of the cell layers than usual. The lamina propria was edematous and showed round cell infiltration mostly lymphocytes and remnants of collagen fibers. By Masson trichrome stain no collagen fibers could be detected in 6 cases, remnants of collagen fibers were seen in the other 23 cases. By periodic acid-Schiff (PAS), positive gland to PAS were seen in 7 cases. The medial epithelium of the retraction pocket specimen showed increased PAS positive granules. In 10 cases there was complete absence of mucosal lining. The semi-thin sections stained with toluidine blue showed finger like projection of stratified squamous epithelium. The lamina propria was infiltrated with round cells and there were no collagen fibers. The ultrastructural study showed thickening of the horny layer (hyperkeratosis). The epithelium showed projection of the basal cell layers of the cell membrane inside the lamina propria. The lamina propria was devoid of collagen fibers in most cases. In 4 cases remnants of collagen fibers were seen. In the fibrous layer, there was degeneration of the circular and radial fibers. There were dilated blood vessels in the lamina propria, in addition inflammatory cells could be seen.