Two cases of epidertnoid cyst of the ovary are added to the ten reported in the literature. This rare lesion is usually an incidental finding. Its main interest is in its histogenesis, which includes metaplasia of the coelomic surface epithelium, monophyletic development of teratoma, and metaplasia of the rete ovarii. We investigated two cases of epidertnoid cyst. Histologic examination of the cysts showed a thin lining of mature keratinizing squamous epithelium rectum: unaccompanied by skin appendages or other teratomatous elements.
Cysts

Five cases of ameloblastoma considered to be originated from the wall of the odontogenic cysts are reported. Histologic characteristics and diagnostic criteria are aimed to study in differentiation of ameloblastoma arising in odontogenic cysts from odontogenic cysts accompanying with reactive epithelial proliferation, and the literature is reviewed. This study can propose that the ameloblastic change and downward growth of epithelial cells lining the cysts are the most important and characteristic findings of the ameloblastoma derived from odontogenic cysts. In addition, the intraluminal proliferation of epithelial cells in plexiform pattern is also significant.
Cysts

Microcystic adenxal carcinoma is an unusual, locally aggressive neoplasm that has recently been recongized as a clincopathologic entity. Its histologic appearance includes both pilar and eccrine differentiation. Microscopically, the tumor consisted of small cysts and gland-like structures in superficial portion. In other area, basaloid cell nests and abortive hair follicles in the sclerotic stroma were seen. The cysts were filled with secretory eosinophilic material, which was positively stained with Periodic acid-Schiff and carcinoembryonic antigen. Immuno-peroxidase staining for carcinoembryonic antigen supported the dual differnetiation of this neoplasm. Despite the benign histologic appearance, there was deep and extensive infiltration of the subcutaneous tissue.
Cysts

Histopathology of pulmonary lymphangioleiomyomatosis(LAM) is studied using four new cases and six previously reported cases, which include two cases without definite evidence of LAM. The important diagnostic features of this lesion were nodular proliferation of immature smooth muscle and cleft or cyst formation within the nodules of smooth muscle cells. The nuclei of the smooth muscle cells were bigger than those of blood vessels or fibrotic lung, and the direction of nuclei was irregular. The lung parenchyma showed little inflammatory change but there were multiple air cysts with smooth muscle nodules at their margin. There were two cases with exuberant proliferation of smooth muscle nodules and two cases with papilliferous projections of the cells into lymphatic lumen. Whereas, three cases had only a few small slender nodules of smooth muscle cells at the margin of air cyst. The lymphatic lumen with smooth muscle nodules is dilated in four cases but other four cases show collapsed lumen. Pulmonary hemorrhage and hemosiderosis were prominent in three cases. There were variety of histology in terms of the cellularity of smooth muscle nodules, the size of the lymphatic lumen and the degree of pulmonary destruction, which may have significance on the clinical presentation and prognostication.
Cysts

In order to elucidate the possibility of diagnosis in soft tissue cysticercosis in case no parasite in it, immunohistochemical staining with antihuman IgG, IgM, and IgA and anticysticercus antibody in tissue section were carried out. Not only the differential counts of infiltrated plasma cells but also the parasite itself against to the anticysticercus antibody were observed. Materials stained immunohistochemically were consisted of 21 soft tissue cysticercosis with or without parasite. The results were as follows: 1) IgG producing plasma cells were most frequent (45.8+/-18.7) and followed by IgM (14.3+/-0.43) and (4.3+/-5.71). Number of IgG plasma cells were more frequently accompanied in the presence of cysticercus (55.9+/-17.7) than in the absence of parasite (39.7+/-17.1). 2) The mean+/-S.D. of plasma cells positive to the anticysticercus antibody were 28.2+/-18.7. And anticysticercus antibody producing plasma cells were more frequent in the presence of cysticercus (49.2+/-5.16) than in the absence of parasite (15.2+/-9.46). 3) Antigenicity of the cysticercus was strong in inner layer(#) followed by tegument(+) and fibrous layer(-). 4) Therefore, it could be suggested that antibody against to the cysticercus is mainly produced by IgG plasma cells and antigenicity of the worm is strong in the inner layer of cyst wall. In addition, there is a possibility of assisting the diagnosis of cysticercosis with anticysticercus antibody by immunohistochemically.
Cysts

Congenital cystic adenomatoid malformation of the lung(CCAML) is a rare developmental anomaly characterized by an "adenomatoid" hyperplasia of terminal respiratory structures with formation of the cysts of varying sizes. CCAML is separated into three major types based on the gross and microscopic findings. We have analyzed 22 cases of CCAML, those consisted of 6 autopsy cases and 16 surgical specimens. Out of 22 cases, 5 cases were composed of large cysts(type I) and 9 cases had multiple small cysts(type II). Remaining one case revealed features of solid type(type III), and 7 cases were mixed form. There were 16 boys and 6 girls. All cases were below the age of 14 years. There was no clear-cut age difference between different types of CCAML. However, inflammation, fibrosis and pseudostratification of epithelium were often found in older age. All fetal autopsy cases of CCAML had hydrops fetalis and were associated with maternal hydramnios. One case of type III showed definite mucinogenic cells in the cysts unexpectedly, and one case of the mixed form(typeI+II+III) was found in a fetus of 22 weeks of gestational age. Above findings contradicted the classical description of the CCAML, and suggested that arbitrary classification into three types may not be the best way in understanding this condition.
Cysts

PURPOSE: Percutaneous aspiration with sclerotherapy has been widely used for the treatment of symptomatic or large simple renal cysts. Ethanol has been most commonly used as a sclerosing agent; however, a temporary percutaneous nephrostomy for multiple ethanol injections is necessary to achieve a low recurrence rate. Thus, we used OK-432 as a new sclerosing agent without a temporary percutaneous nephrostomy for multiple injections, and also compared our results with the results of previous studies. MATERIALS AND METHDOS: Between October 2005 and April 2006, 50 patients (63 simple renal cysts) who underwent percutaneous OK-432 sclerotherapy for simple renal cysts were evaluated. The simple renal cysts were aspirated under ultrasonography and fluoroscopy, after which OK-432 was injected into the cyst. Follow-up was performed with ultrasonography or CT scan after 3 months. Regression of the renal cyst or a >70% reduction in size with no symptoms was considered a treatment success. RESULTS: Among 63 renal cysts in 50 patients, complete regression occurred in 17(27.0%). Greater than a 90% reduction in size occurred in 8(12.7%), a 80-90% reduction in size occurred in 21(33.3%), and a 70-80% reduction in size occurred in 15(23.8%); a <70% reduction in size occurred in 2 (3%). The overall efficacies of success were 96.8%. After the procedure, there were only some minor complications, such as mild fever, local pain, and liver function test elevation that subsided with symptomatic treatment. CONCLUSIONS: Percutaneous OK-432 sclerotherapy is simple, safe, and effective and can be an alternative first-line therapy of simple renal cysts.
Cysts

Congenital cyst of the lung is a type of rare pulmonary disease. This lesion was initially introduced by Morgagni in 1769. Thereafter many other cases were reported. Etiology or developemental pathogenesis of this lesion is not certain, but abnormal developement of embryonic lung bud during the embryonal period is highly suspected. This lesion is two times more frequently located at the left lung, but both sides of the lung may be involved. This lesion is largely asymptomatic and found incidentally but can be evoked respiratory symptoms and also can be died due to only this lesion. So accurate diagnosis and treatment in the early period are very important. Therefore, 32 cases of congenital cyst of the lung reported at the department of pathology, seoul national university hospital from 1. 1986 to 12. 1984 were reviewed and classified with clinical, gross and microscopic findings based on the Buntain's classification. Among 32 cases of congenital cyst of the lung, 16 cases were bronchogenic cysts and were largest in number, 8 cases were pulmonary sequestration, 6 cases were congenital cystic adenomatoid malformation (CCAM) and 2 cases were pulmonary emphysema. In cases of bronchogenic cyst, involved age was variable from 7 months to 51 years and large cases were asymptomatic. Grossly, 15 cases were solitary cyst and only one case was multiple. Size was also variable from 3 cm to 11.5 cm. Microscopically, cyst wall was lined by pseudostratified ciliated columnar epithelium with gobet cells, mucous secreting glands, smooth muscle fibers and fibrous interstitial tissue. Three cases were also exhibit cartilage at the wall. In cases of CCAM, there were involved below the 7 months old boys and girls. Four cases were confirmed at the autopsy, other 2 cases were confirmed at the surgical specimens which were found incidentally or due to generalized cyanosis. Microscopic findings were similar in all cases showing relatively well demarcated multiple small cysts with adenomatous proliferation. Lining epithelial cells were tall columnar, pseudostratified ciliated columnar epithelium with occasional mucous secretion. Stroma also exhibit adenomatous proliferation lined by simple columnar or cuboidal epithelium. In cases of pulmonary sequestration, 7 cases were intrapulmonary, other one case was extrapulmonary sequestration. In five cases, systemic large vessel were confirmed. Microscopically it was composed of irregularly dilated bronchiolar structures lined by pseudostratified ciliated columnar epithelium.
Cysts

We report a case of a large asymptomatic Rathke cleft cyst in a 14-year-old boy. This cyst was of considerable size, measuring 2x1.8x1.8 cm, but did not produce any symptoms and was confined to the suprasellar area. The cyst wall was lined by pseudostratified ciliated columnar epithelium with goblet cells. The lining epithelium of the Rathke cleft cyst was immnoreactive for cytokeratin, EMA and CEA.
Cysts

Cysts of the iris may be primary lesions of either epithelial or stromal in origin, or secondary lesions after trauma or surgery. The stromal cyst is usually of primary lesion, although it could be secondary as shown in our case. We report a case of recurrent iris cyst after trauma. The patient was an 8-year-old girl. She had a penetrating injury of the involved eye three years ago. She had a similar iris cyst removed two years before this surgery. Histologically, the cyst was lined by non-keratinizing stratified squamous epithelia and subjacent fibrovascular tissue. Islands of melanin-containing epithelial cells and acellular basophilic degenerating materials were also seen in the lesion. This case represents a stromal epithelial cyst that by history appears to be of post-traumatic etiology.
Cysts