[Observation and analysis of microstructure and ultrastructure of auricular pseudocyst]

Objective: Through microscopic and ultrastructural observations,to explore the origin of the cartilage of the anteroposterior pseudocyst.Staging for the auricular pseudocyst according to the different pathological changes and exploring its clinical significance. Methods: 48 cases(51 ears)of the auricular pseudocyst were collected as the observation objects(46 males, 2 females, 15-76 years old) and 45 patients(45 ears)chronic suppurative otitis media hospitalized patients who underwent tympanic membrane repair as a normal control group(43 males, 2 females, 12-74 years old).The outer wall of the cyst was surgically resected and the residual auricular cartilage was retained in the control group for HE staining or transmission electron microscopy specimens, and the specimens were observed and analyzed under light microscope and transmission electron microscopy. Results: According to the data of this study, auricular pseudocyst was relatively common in people aged 21-60 years. The disease course of 4 ears was ≤ 10 days,the course of 16 ears was > 10 days yet ≤ 30 days, the course of 20 ears was > 1 month but ≤ 2 months,the course of 6 ears was > 2 months yet ≤ 1 year, the course of 3 ears was > one year but ≤ two years,and the course of 2 ears was > 2 years. The observation of microstructure and ultrastructure of the different course of outer walls of the auricle pseudocyst was shown:due to various causes of cartilage fluid that separated perichondrium and cartilage tissue, when the perichondrium was stimulated, the bone progenitor cells from the quiescence phase came to the activities period. With the extension of the course, the periosteum was thickening gradually, cartilage the bone progenitor cells idifferentiated into chondroblasts, which idifferentiated into chondrocytes last, from native to mature, from thin to thick. It was stable a period of time when the cartilage mature. The outer wall of the cyst was new cartilage, which reflected additional growth. The nucleus of the chondrocytes evolved into nucleolysis, and necrosis, when the lesions was stimulated.The control group had a thin layer of cartilage and periosteum, containing a small amount of osteoprogenitor cells; the cartilage layer was thick, the cartilage cells were small near the periosteum, and the deep cartilage cells were large, all of which were mature chondrocytes. Conclusions: The outer cartilage of auricle pseudocyst is newborn cartilage. The pathological staging is divided into early stage(cartilage formation), middle stage(cartilage maturity) and late stage(cartilage necrosis).This stage can provide a reference for exploring the pathogenesis of pseudocysts of the auricle and formulating surgical treatment principles.