Tumor sólido pseudopapilar de páncreas simulador de pseudoquiste pancreático: descripción de un caso y revisión de la literatura / Solid pseudo-papillary tumor of the pancreas: case report and review of the literature

Introducción: El tumor sólido pseudopapilar de páncreas es un tumor quístico extremadamente infrecuente que se presenta, casi con exclusividad, en mujeres jóvenes. Caso clínico: Se describe el caso de una mujer de 28 años que presenta una tumoración bien delimitada quística con áreas sólidas en cola de páncreas de 6,5 cm. Se le practica pancreatectomía distal. El estudio anatomopatológico evidenció que se trataba de un tumor sólido pseudopapilar de páncreas. Discusión: Estos tumores presentan una morfología muy característica con áreas papilares mezcladas con zonas sólidas que dejan quistes irregulares entremezclados con una variable cantidad de necrosis intraquística. Son tumores que, en general se clasifican dentro de los tumores quísticos de páncreas aunque todavía no está muy claro ni su origen ni su clasificación. Es muy importante su identificación dado su excelente pronóstico tras la cirugía, que resulta curativa en la mayoría de los casos

Introduction: Solid pseudo-papillary tumor of the pancreas is extremely unusual and almost exclusively encountered in young females. Case presentation: We report the case of a 28 year old female with a well defined 6.5 cm tumor in the distal pancreas. A distal pancreatectomy is performed. Histologically, the lesion shows the typical morphology of a solid pseudopapillary tumor of the pancreas. Discussion: This tumor tipically presents papillary and solid areas admixed with cystic changes, and with a variable amount of intracystic necrosis. It is classified as a pancreatic cystic tumor although is not yet clear either the origin or the real classification of the tumor. It is important to identify this tumor because of its excellent prognosis after excision that is almost curative in all cases

Protein cross-linking, peroxidase and beta-1,3-endoglucanase involved in resistance of pea against Orobanche crenata.

Root holoparasitic angiosperms, like Orobanche spp, completely lack chlorophyll and totally depend on their host for their supply of nutrients. O. crenata is a severe constraint to the cultivation of legumes and breeding for resistance remains the most economical, feasible, and environmentally friendly method of control. Due to the lack of resistance in commercial pea cultivars, the use of wild relatives for breeding is necessary, and an understanding of the mechanisms underlying host resistance is needed in order to improve screening for resistance in breeding programmes. Compatible and incompatible interactions between O. crenata and pea have been studied using cytochemical procedures. The parasite was stopped in the host cortex before reaching the central cylinder, and accumulation of H2O2, peroxidases, and callose were detected in neighbouring cells. Protein cross-linking in the host cell walls appears as the mechanism of defence, halting penetration of the parasite. In situ hybridization studies have also shown that a peroxidase and a beta-glucanase are differently expressed in cells of the resistant host (Pf651) near the penetration point. The role of these proteins in the resistance to O. crenata is discussed.

Mucilage production during the incompatible interaction between Orobanche crenata and Vicia sativa.

Orobanche spp. (broomrapes) are holoparasites lacking in chlorophyll and totally dependent on their host for their supply of nutrients. O. crenata is a severe constraint to legumes cultivation and breeding for resistance remains as one of the best available methods of control. However, little is known about the basis of host resistance to broomrapes. It is a multicomponent event, and resistance based on hampering development and necrosis of broomrape tubercles has been reported. In the present work, the formation of mucilage and occlusion of host xylem vessels associated with the death of O. crenata tubercles were studied histologically. Samples of necrotic O. crenata tubercles established on resistant and susceptible vetch genotypes were collected. The samples were fixed, sectioned and stained using different procedures. The sections were observed at the light microscopy level, either under bright field, epi-fluorescence or confocal laser scanning microscopy. A higher proportion of necrotic tubercles was found on the resistant genotype and this was associated with a higher percentage of occluded vessels. Mucilage is composed mainly by carbohydrates (non-esterified pectins) and the presence of polyphenols was also detected. The mucilage and other substances composed by parasite secretions and host-degraded products was found to block host vessels and obstruct the parasite supply channel, being a quantitative defensive response against O. crenata in vetch, and probably also in other legumes and plants. The presence of foreign substances (i.e. parasite secretions) and host-degraded products (i.e. carbohydrates from cell walls) inside host vessels seems to activate this response and leads to xylem occlusion and further death of established Orobanche tubercles.