Gastric Duplication Cyst: Electron Microscopic and Immunohistochemical Study

The lining of a gastric duplication cyst was examined ultrastructurally and immunohistochemically. The cyst lining displayed the range of differentiation seen in normal fundic mucosa.     

Mesothelial cyst of the adrenal gland

A case of mesothelium-lined cyst of the adrenal gland is reported. Although more than 300 adrenal cysts have been reported in the literature, epithelial cell-lined cysts are rare and comprise only 9% of the cases. An adrenal cyst was found, the lining cells of which had features consistent with mesothelial cells. The inner surtace of the cyst was lined by a single layer of cuboidal cells, which showed alcian blue positive cellular outline. Immunohistochemically, the lining cells were positively stained for keratin, epithelial membrane antigen and CA-125. Electron microscopic examination revealed many long complex microvilli and desmosomes in the lining cells. There was a basal lamina beneath the cell layer. These morphological and immunohistochemical findings indicated that the lining cell is derived from mesothelium.     

假腺性神经鞘瘤

目的：探讨假腺性神经鞘瘤的临床和病理学特征,诊断与鉴别诊断及其发生原因。方法：对2例假腺性神经鞘瘤的组织形态和免疫组化表现进行观察与分析。结果：肿瘤组织具有通常型神经鞘瘤结构外,尚有类似上皮细胞衬覆的腺样或囊样腔隙特征,但衬覆腔隙的细胞下面无基膜存在,而与邻近的梭形瘤细胞移行;黏液和免疫组化CK、EMA、CEA染色均阴性,而S-100蛋白和MBP阳性,结论：衬覆腺样或囊样腔隙的细胞仍系神经鞘细胞,肿瘤内的腺样或囊样腔隙及其内衬覆有似上皮细胞的改变可能与肿瘤的变性有关。     

Follicular or dentigerous (tooth-containing) cyst in the premaxilla of an otherwise edentulous 65-year-old man

A unilocular follicular or dentigerous cyst (FDC) with a diameter of 12 mm was observed incidentally in the premaxilla of a midsagittal section of the head of a 65-year-old cadaver. The mucosal lining of the cyst was grey in color and granular in texture: the osseous walls had a thickness of less than 1 mm. In the floor of the cyst, a slender, fully developed incisor tooth was fixed in a horizontal position. The alveolar processes of the maxilla and mandible were completely edentulous. Postmortem computer tomography showed the cyst in an osteolytic lesion of the premaxilla, and histology revealed a lining of non-keratinized stratified squamous epithelium supported by a lamina propria of dense connective tissue. Copyright Wiley-Liss, Inc.     

Multilocular renal cyst. Scanning and transmission electron microscopic observations

A multilocular renal cyst in a boy aged one year and four months is presented, with particular attention being paid to the nature of the epithelial lining cells. Light and transmission electron microscopy showed the cyst to be lined by a single layer of flattened or cuboidal epithelial cells of relatively uniform morphology. Neither embryonic elements nor nephroblastomatous foci were noted in the intervening stroma. The scanning electron microscopy showed hitherto undescribed surface morphological features of the epithelial lining cells: They were characterized by the presence of one or, occasionally two centrally positioned long cilia and by variably oriented microvilli. The observations presented here suggested that the lining cells of the cyst most closely resembled the principal cells of the collecting ducts, especially those located in the inner medulla of the kidney. An unexpected finding was the additional occurrence of a giant bullous lesion in the right lung of this patient.     

Brief Report: Tissue Fixation Methods Alter the Immunohistochemical Demonstrability of Synaptophysin

A 35-year-old man with seizure disorder was found to have a parietal lobe neuroepithelial cyst. The lining of the cyst was made up of ependymal cells containing neuromelanin, which was confirmed ultrastructurally. This appears to be the first report of a pigmented neuroepithelial cyst in the brain parenchyma.     

Localization of immunoreactive keratins in cyst epithelium of chick ultimobranchial glands

The cyst structures of chick ultimobranchial glands were studied by electron microscopy and immunocytochemistry to characterize the type of intermediate-sized filaments present in the cells lining cyst lumina. Electron microscopy showed that the majority of the lumen-bordering cells contained extensive meshworks of intermediate-sized (7-11 nm) filaments, many of which were arranged in bundles. Apical regions of C cells directly bordering on cyst lumina were also filled with thinner (5-6 nm) filaments. Immunoperoxidase staining showed that the majority of cyst epithelial cells were stained intensely with anti-keratin antiserum, but not with anti-neurofilament antiserum, which is a specific marker for neuronal differentiation. The cyst epithelium also showed moderate-to-weak immunoreactivity for actin. Subsequently, the differentiation and maturation of cyst structures related to intermediate filament expression were studied. In 18-day-old chick embryos, keratin immunoreactivity began to appear in the cell clusters destined to form cysts and in the primordial cysts with small cavities. At this time, fine networks of intermediate filaments were already detected in the cells lining the cystic cavities. At 1 day after hatching, the cysts became a consistent feature of ultimobranchial glands. Intermediate filaments associated in bundles were observed, and the intensity of immunostaining for keratins increased. Thereafter, with progressive enlargement of cysts, numbers of intermediate filaments and intensity of keratin immunoreactivity gradually increased with age. Thus, the data indicate that in cyst epithelium keratin filaments are highly organized and may confer the structural strength necessary for cells lining cyst lumina.     

Pigmented Intracerebral Neuroepithelial Cyst: Report of a Case

A 35-year-old man with seizure disorder was found to have a parietal lobe neuroepithelial cyst. The lining of the cyst was made up of ependymal cells containing neuromelanin, which was confirmed ultrastructurally. This appears to be the first report of a pigmented neuroepithelial cyst in the brain parenchyma.     

Cystadenoma of spermatic cord resembling ovarian serous epithelial tumour of low malignant potential: immunohistochemical study suggesting Müllerian differentiation

A cystic lesion of the spermatic cord resembling an ovarian serous epithelial tumour of low malignant potential or borderline malignancy is reported. Immunohistochemical staining and electronmicroscropic examination suggested epithelial rather than mesothelial differentiation of the cyst lining cells. There was strong positive immunohistochemical staining of cyst lining cells for CA 125, providing evidence for Müllerian differentiation. A flow cytometric analysis of nuclear DNA content revealed a diploid profile.     

A rapidly expanding epithelial skull cyst of uncertain origin

A rapidly expanding huge cystic lesion of the skull was the cause of unilateral exophthalmus in a 33 year old man. The differential diagnosis included an aneurysmal bone cyst, keratinous cyst, leptomeningeal cyst and intraosseous hemangioma. Although an epithelial lining was verified, the exact nature of the cyst could not be clarified despite immunohistochemical and electron microscopical investigations.     

Müllerian cysts of the mesentery and retroperitoneum: A case report and literature review

Müllerian cyst of the mesentety and retroperitoneum is an extremely rare disease entity. Only two photomicrograph reports have been published. A 47-yearold Korean woman presented with abdominal distention. A mesenterlc cystic mass, measuring 25 × 23 × 18 cm, was found between the liver and right adnexa without any connection with adjacent organs. The cyst was multilocular with gray-white, rubbery walls of relatively uniform 0.2 cm thickness. Microscopically, the lining cells were ciliated and cuboidal to low columnar with an incomplete lining of smooth muscle bundles, adipose tissues, lymphovascular spaces, and lymphocytic aggregates. Ultrastructurally, the lining cells had Intercellular junctions, and cilia or microvllli on their luminal surface. The lining cells were immunoreactive for cytokeratin, epithelial membrane antigen and vimentin. To the best of our knowledge, this is the first demonstration of ultrastructural and lmmunohistochemical findings of Miillerian cyst of the mesentery and retroperitoneum in the English literature.     

Cutaneous ciliated cyst of the right lower leg

A 23-year-old Japanese woman with a cutaneous ciliated cyst on her right lower leg is reported. A subcutaneous cyst, measuring 2.5 cm in diameter with papillary projections into the lumen, was lined with ciliated cuboidal to columnar epithelia with partial stratification, histologically. These lining cells did not produce mucin. Immunohistochemically, the ciliated lining cells of the cyst were diffusely positive to epithelial membrane antigen and cytokeratin. In addition, positive immunoreaction with anti-desmin monoclonal antibody was observed in the body of the cilia. Less than 10% of the epithelial cells revealed positive immunoreaction to S-100 protein and estrogen receptor.     

Distribution of acetylcholinesterase activity during the development of cysticercoids of Hymenolepis diminuta (Cestoda)

The distribution of acetylcholinesterase (AChE) in oncospheres and developing cysticercoids of Hymenolepis diminuta was examined. The enzyme was localized in the nervous system and in some non-nerve cells of these larvae. In oncospheres AChE was detected in hook muscles and in the binucleated medullar center that is known to enclose two neurons. At early developmental stages of the cysticercoids the enzyme was localized in the post-oncospheral hook muscles and in subtegumental muscle fibers of the cercomer. At medium and late stages of development the activity of AChE was detected in the developing nervous system and in two and, subsequently, in four populations of cells, which gradually spread over the whole internal wall of the cyst, thus forming a thin multilayer AChE-positive lining of the cyst cavity. Following withdrawal of the scolex the lining separates the parenchyma of the turned neck from the cyst tissues and remains AChE-positive during the whole life of the parasite, i.e. up to the death of the infected host. The role played by non-neural AChE associated with the cyst cavity lining is unknown, but seems to regulate both the transport of nutrients and minerals into the scolex and waste substances in the opposite direction.     

Thyroid cyst wall atypia in a patient with a history of malignant melanoma: A pitfall in fine‐needle aspiration cytology

We present an interesting case report from a patient with a history of desmoplastic malignant melanoma (MM), who presented with a thyroid nodule. The patient's clinical diagnosis included a benign thyroid nodule versus a primary thyroid malignancy or metastatic MM. Fine‐needle aspiration biopsy showed highly atypical spindle cells suspicious for metastatic MM. The acellular cell block prevented further studies such as immunohistochemical analysis. The patient underwent surgical excision of the mass, which showed a benign cystic thyroid nodule with an atypical cyst lining. Here, we report the presence of atypical cyst‐lining cells in a patient with diagnosis of MM. The atypical cytology of the cyst‐lining cells has been reported in the English literature; however, presence of significant cytological atypia, especially in a patient with a history of another malignancy, can be problematic. The cytopathologist should be aware of this entity and its diagnostic pitfalls. Diagn. Cytopathol. 2013;41:716–719. © 2013 Wiley Periodicals, Inc.     

The nasolabial cyst: a nonodontogenic oral cyst related to nasolacrimal duct epithelium

Nasolabial cysts are interesting, relatively uncommon benign extraosseous maxillary lesions. We review current knowledge about epidemiology, symptoms, imaging modalities, pathogenesis, histopathologic and ultrastructural features, treatment options, and prognosis. Nasolabial cyst lining epithelium is characteristically composed of a basal layer of cuboidal cells and a luminal layer of columnar secretory cells with interspersed mucous goblet cells. In addition, areas of multilayered epithelium and squamous metaplasia may be seen. The cyst stroma is characterized by collagen-rich fibrovascular tissue with variably admixed chronic inflammatory cells. Furthermore, to our knowledge, we report the first example of immunohistochemical protein expression profiling of nasolabial cyst lining epithelium, discovering that basal layer cells express p63 and cytokeratin 5/6, while goblet cells express MUC-2 and MUC-5AC mucins, supporting the notion that nasolabial cysts can be understood as hamartomatous, locally expansile remnants of distal nasolacrimal duct development.     

Explant culture of human polycystic kidney

Autosomal dominant polycystic kidney disease is characterized by the formation of large fluid-filled epithelial cysts. To obtain renal cyst wall epithelium for in vitro study, we employed an explant culture technique using medium-hydrated collagen gel as the culture substrate. Pieces of excised cyst wall were submerged within collagen gel. Cells of the cyst lining migrated to form a polarized epithelium at the surface of the surrounding collagen gel. Regions of the outgrowth were isolated by microdissection and used as a source of cells for subculture. Cyst-derived epithelium retained the ultrastructural features of the renal cyst of origin. The cells were cuboidal and bore short apical microvilli. Cells often were joined by apical tight junctions. Intercellular channels were narrow and bordered by short microvillus projections at the basolateral membrane. Epithelial cells rested on a densely staining basal lamina. The explants commonly developed small solitary cysts within their wall that were filled with fluid. These mural cysts were lined by a simple epithelium morphologically similar to the cells that lined the explant. Explantation of human renal cyst wall to culture within collagen gel provides a reproducible method to isolate autosomal dominant polycystic kidney disease epithelium for subculture. This method offers an alternative to the use of proteolytic enzymes to establish morphologically stable cultures of cyst lining cells for use in experimental renal cystic disease.     

Fibrinolytic activity in aneurysmal bone cysts.

Euglobulin fibrinolytic activity of cyst fluid from six patients with aneurysmal bone cysys was considerably higher than that of arterial and venous blood of the corresponding patients. The high fibrinolytic activity was associated with a very low concentration of fibrinogen and a low concentration of plasminogen. Correspondingly, a high plasminogen activator activity was found in cyst tissue related to endothelial lining. It is suggested that fibrinolysis is an important factor in the maintenance and expansion of the aneurysmal bone cyst.     

The lining of branchial cysts studied by electron microscopy and enzyme histochemistry

The lining of five branchial cysts from patients aged from 17 to 51 was studied by histochemical methods for non-specific acid esterase and acid phosphatase and by scanning and transmission electron microscopy. The stratified squamous epithelium was shown to be a specialised structure, with a few microvillous cells on the surface and an intra-epithelial network of channels containing lymphocytes, notably T cells, and mononuclear phagocytic cells. The appearance of the cyst lining was similar to that of the epithelium lining the crypts of palatine tonsils. The demonstration of a complex lympho-epithelial lining of the cysts does not settle the controversial question of their origin, but it must be taken into account by hypotheses explaining the development of branchial cysts.     

Foregut duplication cyst of the stomach

Foregut duplication cyst of the stomach is an extremely rare disease entity. A 35-year-old Korean man presented with epigastric pain. An abdominal cystic mass, measuring 7 x 6 x 5 cm, was found in the lesser curvature of the stomach. The cyst was unilocular with a grey-white, rubbery wall. Microscopically, the cyst wall was lined by pseudostratified ciliated, columnar epithelium and gastric mucosa with a complete lining of smooth muscle bundles. Although the origin of this lesion remains uncertain, this case suggests that the gastric cyst arose from the embryonic foregut and showed differentiation toward respiratory and gastric structures.     

Malignant branchiogenic cyst--fact or fiction?

A case of a cystic metastasis of squamous cell carcinoma of palatine tonsil in a 54-year-old male is reported, clinically presenting as a branchiogenic cyst. The grade of differentiation of the squamous cell epithelium lining the cyst was very variable: in some areas it was extremely well differentiated, thus resembling common benign branchial cleft cyst; transition to dysplastic areas with features of carcinoma in situ was visible and finally, in one small focus, invasion of the epithelial structures into the lymphoid tissue was observed. Despite its metastatic nature, the tumor fulfilled histological criteria of a so called malignant branchiogenic cyst (branchiogenic carcinoma). The authors discuss the existence of primary malignant branchiogenic cyst and the criteria necessary for its diagnosis.