Periodic Acid (periodic + acid)

Distribution by Scientific Domains

Terms modified by Periodic Acid

  • periodic acid schiff

  • Selected Abstracts


    Novel Chromium(VI) Catalyzed Oxidation of N-Alkylamides to Imides with Periodic Acid.

    CHEMINFORM, Issue 47 2004
    Liang Xu
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    ChemInform Abstract: Chromium(VI) Oxide-Catalyzed Oxidation of Arenes with Periodic Acid.

    CHEMINFORM, Issue 30 2001
    Shigekazu Yamazaki
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]


    Cutaneous sclerosing perineurioma of the digit

    INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 9 2006
    Toshitsugu Nakamura MD
    An 11-year-old Japanese girl noticed a small nodule, with mild tenderness, on the right index finger 5 years before visiting our outpatient clinic. She had no familial history of neurofibromatosis or past history of traumatic injury at the site of the tumor. Physical examination revealed a slightly elevated, subcutaneous, nodular tumor in the volar aspect between the proximal and distal interphalangeal joints of the digit (Fig. 1A). By magnetic resonance imaging examination, the tumor showed low density on both T1- and T2-weighted images, and was located just adjacent to the tendon with no invasive signs. The tumor was extirpated; at operation, it was well circumscribed and mobile without adhesion to adjacent tendon or nerve, and was easily removed. Figure 1. (a) Slightly elevated subcutaneous tumor (arrow) on the volar aspect of the right index finger. (b) gross appearance of the extirpated tumor, showing a well-circumscribed, whitish solid nodule Grossly, the tumor was a well-circumscribed, firm nodule (10 mm × 8 mm × 5 mm in size) (Fig. 1B). The cut surface was whitish, homogeneous, and solid without cystic lesions. Histologically, it was an unencapsulated, paucicellular dense, fibrous nodule with a concentric circular arrangement of collagen bundles (Fig. 2A). Amongst the fibrous bundles, a small number of ovoid/epithelioid or plump spindle cells were arranged in a corded, trabecular, or whorled (onion bulb-like) pattern (Fig. 2B); a storiform pattern was not noted. These cells were relatively uniform and had a somewhat elongated, slightly hyperchromatic nucleus with fine granular chromatin. Neither nuclear pleomorphism nor multinucleated cells were evident, and necrosis and mitotic figures were not observed. Periodic acid,Schiff (PAS) stain after diastase digestion highlighted the corded or whorled pattern of the tumor cells by encasing them. For immunohistochemical examination, formalin-fixed, paraffin-embedded serial tissue sections were stained by a labeled streptavidin,biotin method. The tumor cells were positive for vimentin and epithelial membrane antigen (EMA) (Fig. 3A), and negative for pan-cytokeratin, carcinoembryonic antigen (CEA), CD34, ,-smooth muscle actin, desmin, and CD68. Type IV collagen and laminin (Fig. 3B) were detected along the cords or whorls of the tumor cells, similar to the staining pattern of the diastase-PAS reaction. Schwann cells and axonal components, immunoreactive for S100 protein and neurofilament, respectively, were focally detected just adjacent to the cords or whorls, although the tumor cells per se did not express these proteins. Consequently, the tumor was found to be perineurial in origin and was diagnosed as cutaneous sclerosing perineurioma. Figure 2. (a) Low-power view of the tumor, showing an unencapsulated, paucicellular, dense, fibrous nodule with a concentric circular arrangement of collagen bundles (hematoxylin and eosin stain: original magnification, ×15). (b) Higher magnification of the tumor, showing ovoid or epithelioid cells arranged in cords or whorls in the abundant collagen bundles (hematoxylin and eosin stain: original magnification, ×150) Figure 3. Immunohistochemical profiles of the tumor. The tumor cells are positive for epithelial membrane antigen (a) and are surrounded by laminin (b) (original magnification, ×150) [source]


    Majocchi's granuloma trichophyticum in an immunocompromised patient

    INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2 2000
    Somesh Gupta MD
    A 40-year-old man with alcoholic liver disease was referred to the dermatology clinic for asymptomatic papulonodular lesions over the face of 15 days' duration. Cutaneous examination revealed multiple, dusky red to yellow, follicular as well as perifollicular papulonodular lesions, varying in size from 0.5 to 2 cm ( Fig. 1). They were distributed over the forehead, cheeks, eyelids, nose, chin, beard area, retroauricular area, and neck. Careful examination revealed well-defined scaly margins on the back of the pinna ( Fig. 2). KOH examination of a scraping from the neck revealed nonpigmented septate hyphae. Histopathologic examination of the excised nodule revealed epitheloid cell granulomas with neutrophilic microabscesses surrounding the hair follicles. Periodic acid,Schiff stain was noncontributory. Culture of an excised nodule on Sabouraud's agar showed growth of Trichophyton rubrum. Considering his liver disease, the patient was initially treated with topical terbinafine. Because of a lack of a satisfactory response this was changed to oral terbinafine 250 mg/day. There was marked regression of the lesions by the sixth day. Unfortunately, the patient succumbed to complications relating to his liver disease. Figure 1. Follicular and perifollicular lesions of Majocchi's granuloma Figure 2. A well-defined scaly margin of tinea on the back of the pina [source]


    Adhesion and development of the root rot fungus (Heterobasidion annosum) on conifer tissues: effects of spore and host surface constituents

    FEMS MICROBIOLOGY ECOLOGY, Issue 2 2000
    Frederick O Asiegbu
    Abstract The objective of this study was to correlate the occurrence of particular root and woody stump surface components with the ability of spores of the root rot fungus (Heterobasidion annosum) to adhere, germinate and establish on conifer tissues. With the aid of high performance liquid chromatography, several sugars (pinitol, xylitol, dulcitol, mannitol, D -glucose, mannose, fructose) were detected on both stump and fine root surfaces of Scots pine and Norway spruce. Of all the sugars observed, xylose and arabinose were poorly utilized for initiation of germ tube growth whereas spore germination was enhanced in the presence of D -glucose, mannose or fructose. Oxidation of these sugars by pretreatment of wood discs or roots with periodic acid abolished the ability of the spores to germinate. Non-sugar components such as long chain fatty acids on spores and root surfaces as detected with nuclear magnetic resonance were found to have a significant influence on adhesion and initiation of germ tube development. Removal of these aliphatic compounds from the root surface increased spore germination by 2-fold, whereas similar treatment on spores led to a 5-fold decrease in adhesiveness to root material. In vitro studies revealed that the di-ethyl ether extract from the roots had no long term adverse effect on spore germination which suggests that the fungus may possess the capability to detoxify this substance. Similarly, adhesion of spores was affected by low and freezing temperatures. The role of significant levels of mannitol and trehalose accumulated in spores and hyphae of the fungi on viability, survival and tolerance to adverse conditions such as oxidative stress, freezing and desiccation are discussed. [source]


    Isolation and characterization of epithelial progenitor cells from human fetal liver

    HEPATOLOGY RESEARCH, Issue 1 2008
    Yi-Nan Liu
    Aim:, Hepatic progenitor cells can serve as an alternative source of hepatocytes for the treatment of liver diseases. Methods:, We isolated and expanded the epithelial progenitor cells (EPC) from the human fetal liver and investigated the differentiation of EPC into hepatic cells by fluorescence-activated cell sorter (FACS), real-time polymerase chain reaction (PCR), immunofluorescence assay, western blotting, and periodic acid,Schiff staining. Results:, Isolated EPC possessed highly proliferative ability and subpassaged for more than 25 passages. Real-time PCR showed that EPC expressed liver epithelial markers (cytokeratin [CK]8 and CK18) and biliary-specific markers (CK7 and CK19). FACS analysis indicated that these cells were positive for CD117, CD147, CD90, CD44, human leucocyte antigen class I and CD71, but negative for CD34 and CD45. The EPCpossessed multipotential indicated by differentiating into osteoblasts and adipocytes; when subjected to the hepatic differentiation condition, EPC could be induced to hepatocyte-like cells, which expressed albumin, alpha-fetoprotein, and CK18 proteins. Two months after EPC transplantation, we observed that the grafted cells differentiated into hepatocyte-like cells and there was no observable tumor mass. Conclusion:, We have isolated and characterized the human fetal liver-derived EPC and these cells may serve as an ideal cell source for cell-replacement therapy of diseased livers. [source]


    Unequivocal morphological diagnosis of fungi in morphologically abnormal nails

    HISTOPATHOLOGY, Issue 7 2006
    A Cabral
    Aims :,To analyse the prevalence of fungi in abnormal nails by morphological diagnosis. Prevalence studies of onychomycoses in temperate climate zones have yielded widely varying rates, possibly reflecting the confounding effects of referral bias, sampling specificity and intrinsic sensitivity of the diagnostic techniques employed. Methods and results :,The method employed to identify fungi in nails entailed primary fixation using a non-formaldehyde-based coagulative fixative (BoonFix®; Finetec, Japan) and microwave-enhanced processing to histology, followed by staining the paraffin sections with periodic acid,Schiff, using haematoxylin as a routine counterstain. The results of 990 nail samples were tabled for statistical analysis related to gender, patient age and diabetes mellitus status. In four of the 990 (< 1%) analysed cases the diagnosis was found to be equivocal using the method employed. These cases were jointly reviewed for definitive diagnosis. The overall prevalence of invasive hyphal structures was found to be 606/990 (, 61%). The relative risk for fungal infection in morphologically abnormal nails was found to be higher for persons <,20 years old or diabetic patients aged ,,71 years. Conclusions :,The 61% positivity rate for fungi found justifies systematic direct submission of samples from abnormal nails for histological confirmation in order to avoid unwarranted treatment. [source]


    Pseudoepitheliomatous hyperplasia , an unusual reaction following tattoo: report of a case and review of the literature

    INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 7 2007
    Wei Cui MD
    A 59-year-old woman presented with an itchy and uncomfortable raised lesion at a tattoo site (Fig. 1) on the lateral aspect of the left leg, just above the ankle. The tattoo had been placed 2 years before her presentation and the tattoo site was sun exposed. Immediately after she had the tattoo, she noticed redness of the skin. After a week, a pruritic and red scaly nodule developed that continued to gradually enlarge until her presentation. The patient had tried topical vitamin A and D ointment with no relief. The patient also had tattoos on the arms without any noticeable skin changes. The patient reported that the tattoo procedure on her leg was more painful than that on her arms, and was performed by a different (and perhaps inexperienced) tattoo artist. The original tattoo contained red, green, and yellow pigments. Figure 1. Raised nodular lesion with irregular margins A diagnosis of tattoo granuloma was considered; squamous cell carcinoma and fungal infection were included in the differential diagnosis. A punch biopsy was performed, followed by complete surgical excision of the lesion with a split-thickness skin graft from the right thigh. The skin excision specimen showed a 3 × 2.5-cm granular and pitted pink lesion with well-demarcated, somewhat irregular borders. The lesion was raised 0.5 cm above the skin surface. The lesion was present in the center of the original tattoo. Portions of the original tattoo with green and blue,green pigmentation were visible on either side of the lesion. No satellite lesions were identified. Microscopically, the raised lesion demonstrated striking pseudoepitheliomatous hyperplasia, with irregular acanthosis of the epidermis and follicular infundibula, hyperkeratosis, and parakeratosis (Fig. 2). Follicular plugging was present with keratin-filled cystic spaces. There was a brisk mononuclear inflammatory infiltrate in the dermis, composed primarily of lymphocytes, with admixed plasma cells and histiocytes. Giant cells were occasionally identified. Dermal pigment deposition was noted both within the lesion and in the surrounding skin, corresponding to the original tattoo. Variable dermal fibrosis was noted, with thick collagen bundles in some areas. There was no evidence of epidermal keratinocytic atypia, dyskeratosis, or increased suprabasal mitotic activity. Special stains (periodic acid,Schiff and acid-fast) for microorganisms were negative. Figure 2. (a) Raised lesion with marked pseudoepitheliomatous hyperplasia and follicular plugging (hematoxylin and eosin; magnification, ×2.5). (b) Irregularly elongated and thickened rete pegs with blunt ends associated with dermal chronic inflammation (hematoxylin and eosin; magnification, ×5). (c) Follicular dilation and plugging with keratin-filled cystic spaces (hematoxylin and eosin; magnification, ×5). (d) Dermal pigment and fibrosis (hematoxylin and eosin; magnification, ×10) [source]


    S-100-negative atypical granular cell tumor: report of a case

    INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 3 2002
    Mi-Woo Lee MD
    A 38-year-old man presented with a solitary, round, 1.2 × 1.2 cm, bluish-colored, dome-shaped, hard nodule on the left side of the neck, which had grown over 2 months (Fig. 1). The nodule was nontender and nonmovable. Light microscopy revealed that the neoplasm was situated in the reticular dermis with extension into the papillary dermis. The tumor showed expansile growth with smooth and round borders, and was made up of sheets of cells arranged in nests or lobules separated by thin delicate connective tissue septa. The tumor cells were round, oval, or polygonal in shape with distinct cellular borders. The cells had abundant eosinophilic granular cytoplasm, and considerable variation of cellular and nuclear size was noted (Fig. 2a). The tumor cell nuclei were vesicular and some had pleomorphism (Fig. 2b). Sometimes multiple nucleoli were seen. Mitoses and necrosis were virtually absent. Immunohistochemical staining revealed that some of the cytoplasmic granules stained positively with periodic acid,Schiff (PAS) after diastase treatment. Tumor cells showed strong reactivity for CD68 and neuron-specific enolase, and negative results for S-100, factor XIIIa, cytokeratin, desmin, CD34, and smooth muscle actin. Electron microscopy revealed that the tumor was composed of polygonal cells with round to irregular nuclei, and the cytoplasm contained numerous secondary lysosomes. The tumor was completely excised. Figure 1. A solitary, round, 1.2 × 1.2 cm, bluish-colored, dome-shaped, hard nodule on the left side of the neck Figure 2. (a) Tumor cells contain granular cytoplasm and show atypical cytologic features (b) Neoplastic cells show variation of cell size and nuclear pleomorphism [source]


    Different distribution of immunocompetent cells in the dentogingival junction during root formation in rat molars

    JOURNAL OF PERIODONTAL RESEARCH, Issue 1 2003
    Hiroshi Tamura
    The distribution of immunocompetent cells in the dentogingival junction of rat molars during root formation was investigated by immunocytochemistry using antibodies to class II major histocompatibility complex (MHC) molecules (OX6-antibody) and monocyte/macrophage lineage cells (ED1-antibody) as well as by histochemical reaction for periodic acid,Schiff (PAS). Two portions (the junctional epithelium in the mesial gingiva of the first molar, and the interdental gingiva between the first and second molars) were selected for observations. At the eruption stage of the first molar (16,18 days after birth), OX6-positive cells, dendritic or oval in shape, were abundantly distributed in the connective tissue between the oral epithelium and tooth germ. Positive cells with slender cell processes were also found beneath the ameloblast layer. At the commencement stage of the first molar occlusion (24,28 days after birth), numerous OX6-positive cells displaying a dendritic fashion existed preferentially in the mesial gingiva, but were fewer in the interdental gingiva. In contrast, the interdental gingiva showed a denser distribution of ED1-positive cells and PAS-reactive polymorphonuclear leukocytes (PMLs) than the mesial gingiva. At the completion stage of root formation (100,120 days after birth), the OX6-immunopositive cells invaded the deeper position of the mesial gingiva with the downgrowth of the epithelium; they had a considerably higher cell density compared with those in the interdental gingiva where PAS-reactive PMLs persisted. These findings indicated that the immunocompetent cells showed a region-specific distribution and cell density by their roles in immune response. [source]


    Oral and vaginal epithelial cell anti- Candida activity is acid labile and does not require live epithelial cells

    MOLECULAR ORAL MICROBIOLOGY, Issue 4 2005
    J. Yano
    Background:,Candida albicans is the causative agent of oral and vaginal candidiasis. Innate host defenses against C. albicans are important against each infection. Among these are oral and vaginal epithelial cells that have anti- Candida activity. The mechanism of action includes a requirement for cell contact with no role for soluble factors, and a putative role for carbohydrates based on the sensitivity of the activity to periodic acid. Methods:, Periodic acid treatment of epithelial cells as well as the property of partial resistance of antifungal activity to fixation was used to further dissect the mechanism of action. Results:, The results herein effectively now challenge a role for carbohydrates alone. Firstly, the putative carbohydrate(s) released into supernatants of periodic acid-treated epithelial cells could not compete with fresh epithelial cells for activity, and equivalent abrogation of activity was observed by periodic acid-treated cells irrespective of the amount of carbohydrate released. Instead, the similar abrogation of activity following treatment with other acids or when cocultured under acidic conditions suggests that the activity is acid-labile. Finally, while activity requires intact epithelial cells, it does not require live cells; activity was minimally affected by fixing epithelial cells prior to coculture where the majority of cells remained impermeable to Trypan blue but were defined as non,viable by positive nuclear staining with propidium iodide. Conclusion:, These results suggest that antifungal activity is dependent on contact by intact, but not necessarily live, epithelial cells through an acid-labile mechanism. [source]


    Antigenic properties of the GroEL-like protein of Campylobacter rectus

    MOLECULAR ORAL MICROBIOLOGY, Issue 1 2002
    D. Hinode
    The purpose of this study was to clarify the antigenic properties of the GroEL-like protein of Campylobacter rectus using a specific polyclonal antibody directed to the purified 64-kDa GroEL-like protein (pAb- CrGroEL), a polyclonal antibody directed to the Actinobacillus actinomycetemcomitans GroEL-like protein (pAb- AaGroEL) and a monoclonal antibody against the recombinant human HSP60 (mAb-HuHSP60). In SDS-PAGE/Western immunoblotting analysis, mAb-HuHSP60, pAb- CrGroEL and pAb- AaGroEL were found to react with the GroEL-like protein (64-kDa) present in all C. rectus strains. A 150-kDa protein in C. rectus ATCC 33238 also reacted strongly with pAb- CrGroEL. This 150-kDa protein was found to be present on the surface-associated material of bacterial cells, as determined by transmission electron microscopy and immunogold labelling of cells with pAb- CrGroEL. Analysis of the first 20 N -terminal amino acids of the sequence of the 150-kDa protein revealed a strong homology (80%) with the C. rectus surface layer (S-layer) protein. Investigation of the biochemical nature of antigenic determinants using periodic acid and proteolytic enzymes showed that the C. rectus GroEL-like protein possessed immunodominant epitopes in both peptide and carbohydrate chains, and that the immunoreactive determinants of the 150-kDa protein belonged to carbohydrate. These results suggest that the GroEL-like protein and the S-layer protein of C. rectus may share the same carbohydrate epitopes. [source]


    Factors in the Pathogenesis of Tumors of the Sphenoid and Maxillary Sinuses: A Comparative Study,

    THE LARYNGOSCOPE, Issue S96 2000
    Anthony J. Reino MD
    Abstract Objectives/Hypothesis To explain the processes that lead to the development of tumors in the maxillary and sphenoid sinuses. Study Design A 32-year review of the world's literature on neoplasms of these two sinuses and a randomized case-controlled study comparing the normal mucosal architecture of the maxillary to the sphenoid sinus. Methods Analysis of a 32-year world literature review reporting series of cases of maxillary and sphenoid sinus tumors. Tumors were classified by histological type and separated into subgroups if an individual incidence rate was reported. Histomorphometry of normal maxillary and sphenoid sinus mucosa was performed in 14 randomly selected patients (10 sphenoid and 4 maxillary specimens). Specimens were fixed in 10% formalin, embedded in paraffin, and stained with periodic acid,Schiff (PAS) and hematoxylin. Histomorphometric analysis was performed with a Zeiss Axioscope light microscope (Carl Zeiss Inc., Thornwood, NY) mounted with a Hamamatsu (Hamamatsu Photonics, Tokyo, Japan) color-chilled 3 charge coupled device digital camera. The images were captured on a 17-inch Sony (Sony Corp., Tokyo, Japan) multiscan monitor and analyzed with a Samba 4000 Image Analysis Program (Samba Corp., Los Angeles, CA). Five random areas were selected from strips of epithelium removed from each sinus, and goblet and basal cell measurements were made at magnifications ×100 and ×400. Results The literature review revealed that the number and variety of tumors in the maxillary sinus are much greater than those in the sphenoid. The incidence of metastatic lesions to each sinus is approximately equal. No recognized pattern of spread from any particular organ system could be determined. On histomorphometric study there were no statistically significant differences between the sinuses in the concentration of goblet cells, basal cells, or seromucinous glands. Conclusions Factors involved in the pathogenesis of tumors of the maxillary and sphenoid sinuses include differences in nasal physiology, embryology, morphology, and topography. There are no significant histological differences in the epithelium and submucous glands between the two sinuses to explain the dissimilar formation of neoplasms. [source]


    Structural and Histochemical Studies on the Teleostean Bulbus Arteriosus

    ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2009
    I. L. Leknes
    Summary The structure and histochemical properties of the bulbus arteriosus in two species from an evolutionary old teleost family, Characidae, and in three modern teleosts, family Cichlidae, are described. The bulbar wall was composed of an outer layer, a middle layer and a strongly folded inner layer covered by a thick, granule-rich endothelial cell layer towards the lumen. One of the cichlid species (Thorichthys meeki) was injected intraperitoneally with horse ferritin; the endothelial cell layer of the heart atrium and ventricle displayed high ability to endocytose ferritin particles from the blood stream, but the corresponding layer in the bulbus arteriosus displayed no such uptake. This finding suggests that the bulbar endothelial cell layer plays no scavenger or immunological blood cleansing roles in this species. The bulbar endothelial cell granules were strongly coloured by periodic acid,Schiff (PAS) in the present cichlids, but weakly coloured by PAS in the present characids. These cell layers were uncoloured by alkaline carmine in ethanol in both cichlids and characids. The negative carmine test combined with a positive PAS test for the bulbar endothelial cell layer in the present cichlids indicates that these cells contain only small amounts of polysaccharides. The weak PAS-colouring for the bulbar endothelial cell layer in characids indicates a very low content of sugars in these cells. These findings together with the fact that this cell layer in the present cichlids and characids was nearly uncoloured when treated with orcein, Heidenhain's Azan or Schmorl's solutions for elastic materials suggest that the bulbar endothelial granules do not play any role in the blood cleansing or in the rebuilding or maintenance of the ground substance or elastic material in the bulbar wall. Probably, the granules in the bulbar endothelial cell layer in the present species contain mainly proteins, connected to some PAS-positive polysaccharides to enhance their solubility. [source]


    Idiopathic acquired generalized anhidrosis due to occlusion of proximal coiled ducts

    BRITISH JOURNAL OF DERMATOLOGY, Issue 3 2004
    J. Ogino
    Summary Idiopathic acquired generalized anhidrosis is a very rare disease of unknown pathogenesis. We report a 25-year-old man with acquired generalized anhidrosis due to occlusion of the coiled ducts. He did not have sweat secretion over the entire surface of the body, including the palms and soles. Sweat-inducing stimuli provoked tingling pain on the skin. Pilocarpine iontophoresis on the forearm did not induce sweat secretion. Neurological examination did not reveal any abnormality in the central or peripheral nervous system. Skin biopsy showed that the coiled ducts were occluded by an amorphous eosinophilic substance. This amorphous eosinophilic substance was positive with periodic acid,Schiff (PAS) staining and was resistant to digestion by diastase. Electron microscopy demonstrated that the coiled ducts were completely occluded by an amorphous substance. The substance occluding the coiled ducts contained fibrous structures. These findings suggested that the acquired generalized anhidrosis in this patient was caused by occlusion of the coiled ducts by a PAS-positive substance probably derived from dark cell granules. [source]


    Investigation of vasculogenic mimicry in sebaceous carcinoma of the eyelid

    ACTA OPHTHALMOLOGICA, Issue 5 2010
    Xiaofang Xu
    Abstract. Purpose:, Vasculogenic mimicry (VM) is a newly proposed pattern of tumour angiogenesis that has been identified in some malignancies and is associated with poor prognosis. The purpose of this study was to investigate whether sebaceous carcinomas of the eyelid exhibit VM and to determine whether these fluid-conducting patterns are associated with clinicopathologic features, the number of microvessels and the levels of endothelial growth factor (VEGF) and matrix metalloprotease-2 (MMP-2) in tumours. Methods:, Forty paraffin-embedded samples of sebaceous carcinoma of the eyelid were collected, along with complete clinical and pathologic data for all the cases. Tissue sections were stained for CD34, periodic acid and Schiff (PAS), VEGF and MMP-2. VM was identified by the presence of PAS-positive and CD34-negative loops lined by tumour cells. The VM status of tumour samples was compared with the clinical and pathological data using statistical tests. The levels of VEGF, MMP-2 and the number of microvessels were compared between patients with and without VM. Results:, VM was detected in 14 of 40 (35%) tumour samples. The existence of VM in tumours was associated with tumour size (p = 0.007) and recurrence (p = 0.021). The number of microvessels was lower in tumours with VM (13.03 ± 4.02 versus 22.99 ± 7.72; p < 0.0001). The staining index of MMP-2 was higher in tumours with VM (27.43, range: 0,5.3) compared to tumours without VM (16.77, range: 0,2.7; p = 0.004). However, there was no difference in the expression of VEGF between groups with and without VM (p = 0.244). Conclusions:, Vasculogenic mimicry is present in sebaceous carcinoma of the eyelid making it an unfavourable prognosis sign. MMP-2 is associated with VM formation in sebaceous carcinoma of the eyelid. [source]