Sacral nerve root cysts: A review on pathophysiology.
(9/1471)
Nerve root cysts of the sacral region are generally asymptomatic but are known to cause neurogenic claudication. In this paper we present an elderly lady who presented with claudication, whose MR imaging showed a sacral cyst. She underwent lumbo-sacral laminectomy, partial excision of the cyst wall with plication. A review of the possible pathophysiology of such a lesion is discussed. (+info)
Apc1638T: a mouse model delineating critical domains of the adenomatous polyposis coli protein involved in tumorigenesis and development.
(10/1471)
The adenomatous polyposis coli (APC) gene is considered as the true gatekeeper of colonic epithelial proliferation: It is mutated in the majority of colorectal tumors, and mutations occur at early stages of tumor development in mouse and man. These mutant proteins lack most of the seven 20-amino-acid repeats and all SAMP motifs that have been associated with down-regulation of intracellular beta-catenin levels. In addition, they lack the carboxy-terminal domains that bind to DLG, EB1, and microtubulin. APC also appears to be essential in development because homozygosity for mouse Apc mutations invariably results in early embryonic lethality. Here, we describe the generation of a mouse model carrying a targeted mutation at codon 1638 of the mouse Apc gene, Apc1638T, resulting in a truncated Apc protein encompassing three of the seven 20 amino acid repeats and one SAMP motif, but missing all of the carboxy-terminal domains thought to be associated with tumorigenesis. Surprisingly, homozygosity for the Apc1638T mutation is compatible with postnatal life. However, homozygous mutant animals are characterized by growth retardation, a reduced postnatal viability on the B6 genetic background, the absence of preputial glands, and the formation of nipple-associated cysts. Most importantly, Apc1638T/1638T animals that survive to adulthood are tumor free. Although the full complement of Apc1638T is sufficient for proper beta-catenin signaling, dosage reductions of the truncated protein result in increasingly severe defects in beta-catenin regulation. The SAMP motif retained in Apc1638T also appears to be important for this function as shown by analysis of the Apc1572T protein in which its targeted deletion results in a further reduction in the ability of properly controlling beta-catenin/Tcf signaling. These results indicate that the association with DLG, EB1, and microtubulin is less critical for the maintenance of homeostasis by APC than has been suggested previously, and that proper beta-catenin regulation by APC appears to be required for normal embryonic development and tumor suppression. (+info)
Adenocarcinoma within a rectal duplication cyst: case report and literature review.
(11/1471)
Intestinal duplications are uncommon but recognised developmental anomalies. Duplications of the rectum are the most uncommon of these anomalies. They may present with perianal fistulae, bleeding, a pelvic mass or symptoms produced by a mass, or, rarely, malignant change. We present a case of an adenocarcinoma within a rectal duplication cyst which was initially thought to be inoperable but was treated by radical surgery. (+info)
Iris cysts in children: classification, incidence, and management. The 1998 Torrence A Makley Jr Lecture.
(12/1471)
BACKGROUND: Iris cysts in children are uncommon and there is relatively little information on their classification, incidence, and management. METHODS: The records of all children under age 20 years who were diagnosed with iris cyst were reviewed and the types and incidence of iris cysts of childhood determined. Based on these observations recommendations were made regarding management of iris cysts in children. RESULTS: Of 57 iris cysts in children, 53 were primary and four were secondary. There were 44 primary cysts of the iris pigment epithelium, 34 of which were of the peripheral or iridociliary type, accounting for 59% of all childhood iris cysts. It was most commonly diagnosed in the teenage years, more common in girls (68%), was not recognised in infancy, remained stationary or regressed, and required no treatment. The five mid-zonal pigment epithelial cysts were diagnosed at a mean age of 14 years, were more common in boys (83%), remained stationary, and required no treatment. The pupillary type of pigment epithelial cyst was generally recognised in infancy and, despite involvement of the pupillary aperture, also required no treatment. There were nine cases of primary iris stromal cysts, accounting for 16% of all childhood iris cysts. This cyst was usually diagnosed in infancy, was generally progressive, and required treatment in eight of the nine cases, usually by aspiration and cryotherapy or surgical resection. Among the secondary iris cysts, two were post-traumatic epithelial ingrowth cysts and two were tumour induced cysts, one arising from an intraocular lacrimal gland choristoma and one adjacent to a peripheral iris naevus. CONCLUSIONS: Most iris cysts of childhood are primary pigment epithelial cysts and require no treatment. However, the iris stromal cyst, usually recognised in infancy, is generally an aggressive lesion that requires treatment by aspiration or surgical excision. (+info)
Role of fibronectin deposition in cystogenesis of Madin-Darby canine kidney cells.
(13/1471)
BACKGROUND: Madin-Darby canine kidney (MDCK) cells cultured within collagen I gel exhibit clonal growth and form spherical multicellular cysts. The cyst-lining epithelial cells are polarized with the basolateral surface in contact with the collagen gel and the apical surface facing the lumen. To understand whether MDCK cysts construct the basal lamina, we characterized the composition of the extracellular matrix deposited by MDCK cysts. The cyst-lining cells produced an apparently incomplete basal lamina containing a discontinuous laminin substratum. In addition, the basal cell surface of the cyst was surrounded by a thick layer of fibronectin. This study was conducted to delineate the role of fibronectin deposition in cystogenesis. METHODS: MDCK cells cultured in collagen gel were employed. We first used Arg-Gly-Asp (RGD) peptides containing disintegrin rhodostomin to disturb the interaction between fibronectin and the cell surface integrin. We then established several stable transfectants expressing the fibronectin antisense RNA and with which to directly examine the role of fibronectin in cystogenesis. RESULTS: Rhodostomin markedly decreased the growth rates of the MDCK cyst, suggesting the importance of a normal interaction between fibronectin and integrins. The stable transfectants overexpressing the fibronectin antisense RNA exhibited relatively lower levels of fibronectin and markedly lower cyst growth rates than the control clone. The lower growth rate was correlated with an increase in collagen gel-induced apoptosis. CONCLUSIONS: The results indicate that the deposition of fibronectin underlying the cyst-lining epithelium serves to prevent apoptosis induced by three-dimensional collagen gel cultures, and hence facilitates cyst growth of MDCK cells. (+info)
Management of antenatally diagnosed pulmonary sequestration associated with congenital cystic adenomatoid malformation.
(14/1471)
BACKGROUND: Sequestration with associated cystic adenomatoid malformation is rare. A study was undertaken to determine whether pulmonary sequestration associated with congenital cystic adenomatoid malformation has a more favourable natural history than that of sequestration without associated cystic adenomatoid malformation. METHODS: An outline of the postnatal work up leading to the management of extralobar or intralobar pulmonary sequestration with congenital cystic adenomatoid malformation diagnosed antenatally as pulmonary malformation is presented and the indications for surgical intervention are discussed. RESULTS: In five infants in whom an antenatal ultrasound scan had detected a congenital lung malformation at 18-19 weeks gestation a final diagnosis of extralobar or intralobar pulmonary sequestration with congenital cystic adenomatoid malformation was made postnatally. Postnatal ultrasound and computerised axial tomographic scans confirmed the diagnosis of sequestration by delineating anomalous vascular supply. Cystic changes were also observed in the basal area of the sequestration in all patients. Four children remained asymptomatic and one infant presented at 10 months of age with pneumonia. The mean age at surgical resection was 6.8 months (range 2-10). Histopathological examination confirmed intralobar pulmonary sequestration with associated Stocker type 2 congenital cystic adenomatoid malformation in two patients and extralobar pulmonary sequestration with associated Stocker type 2 congenital cystic adenomatoid malformation in three patients. The mean period of follow up was four years (range 1-8). The children remain well and are developing normally. CONCLUSIONS: The importance of seeking an anomalous blood supply in children with congenital lung lesions is emphasised. Pulmonary sequestration and congenital cystic adenomatoid malformation probably share a common embryogenesis despite diverse morphology. The natural history of antenatally diagnosed lung masses is variable. Early postnatal surgical resection of pulmonary sequestration with cystic adenomatoid malformation is recommended. Surgical excision should be conservative, sparing the normal lung parenchyma. (+info)
Symptomatic Rathke's cleft cyst coexisting with central diabetes insipidus and hypophysitis: case report.
(15/1471)
We describe a 48-year-old female with acute onset of central diabetes insipidus followed by mild anterior pituitary dysfunction. Magnetic resonance imaging (MRI) revealed enlargement of the hypophysis-infundibulum accompanied by a cystic component. She underwent a transsphenoidal exploration of the sella turcica. Histological examination showed foreign body type xanthogranulomatous inflammation in the neurohypophysis which might have been caused by rupture of a Rathke's cleft cyst. The MRI abnormalities and anterior pituitary dysfunction improved after a short course of corticosteroid administration, but the diabetes insipidus persisted. The histological findings in this case indicated the site of RCC rupture and the direction of the progression of RCC induced neurohypophysitis and adenohypophysitis. (+info)
Epitheliocystis agents in sea bream Sparus aurata: morphological evidence for two distinct chlamydia-like developmental cycles.
(16/1471)
The morphology of membrane-bound intracellular inclusions, or 'cysts', of epitheliocystis from sea bream Sparus aurata is described. Inclusions under the light microscope appear either granular or amorphous. Granular inclusions do not elicit a proliferative host reaction and contain the 3 distinctive developmental stages of chlamydial organisms: the highly pleomorphic reproductive form or reticulate body, the condensing form or intermediate body and the infective non-dividing rather uniform elementary body. Amorphous inclusions may elicit a proliferative host reaction and contain prokaryotic organisms which differ morphologically from those reported within granular cysts. More or less elongated electron-lucent organisms divide by fission to give rise to electron-dense non-dividing small cells with a dense nucleoid. Vacuolated and non-vacuolated small cells are reported. The morphology and developmental cycle of sea bream epitheliocystis agents would support their chlamydial nature; however, the immunohistochemical study conducted on gill samples which carried both inclusions failed to demonstrate the expression of lipopolysaccharide (LPS) chlamydial antigen. The different stages of the 2 distinct developmental cycles described in the present study are compared with electron microscope observations of epitheliocystis organisms reported from different host species. The hypothesis that epitheliocystis infection in the sea bream might be caused by a unique highly pleomorphic chlamydia-like agent, the life history of which includes 2 entirely different developmental cycles, is discussed. (+info)