Týmus je primárny lymfatický orgán s dôležitou endokrinnou funkciou. Lokalizovaný je v hornom mediastíne, u novorodencov zasahuje do predného mediastína. Morfológia týmusu sa značne líši dokonca v rovnakej vekovej kategórii. U mladých jedincov je tvorený dvoma asymetrickými lalokmi a má tvar písmena „V“, pričom výbežky kraniálne siahajú do krčnej oblasti. Anomálie tvaru, veľkosti a lokalizácie týmusu možno vysvetliť narušením vývinu základu týmusu v hltanovej oblasti embrya a/alebo narušením jeho zostupu z oblasti krku do mediastína. Medzi najčastejšie anomálie týmusu zaraďujeme odchýlky v počte lalokov, ektopický týmus, prídavné tkanivo týmusu, apláziu týmusu, kombinovanú apláziu týmusu a prištítnych teliesok (DiGeorgeov syndróm), hypopláziu a hyperpláziu týmusu. V súčasnej literatúre je značná nejednota v klasifikácii anomálií týmusu, na ktoré v našom príspevku poukazujeme. Opierame sa pri tom o poznatky o vývine týmusu a postupujeme podľa odporúčania medzinárodnej Terminologia Embryologica. Cystická forma akcesórneho tkaniva týmusu lokalizovaného na krku sa označuje ako „vrodená krčná cysta týmusu“. Týmofaryngová krčná cysta je ďalší špeciálny a veľmi vzácny variant akcesórneho cystického tkaniva týmusu. Pomerne častá a asymptomatická anatomická variácia je fúzia týmusu s jedným alebo s viacerými prištítnymi telieskami.

Thymus is a central lymphoid organ with an important endocrine function located in the superior mediastinum, but in newborns it caudally reaches to anterior mediastinum. Thymic morphology varies greatly even in the same age group. For instance, in young adults, it is typically bilobed and V-shaped, with two small processes extending into the neck. Anomalies of the thymic shape, size and localization are explained by the disruption of thymic primordia formation and/or disruption of its descent from the neck to the mediastinum. The most common thymic anomalies include anomalies in number of the thymic lobes, ectopic thymus, accessory thymic tissue, thymic aplasia, thymoparathyroid aplasia (DiGeorge syndrome), thymic hypoplasia and hyperplasia. In a case of ectopic thymus, the whole thymus is (most often) located in the midline neck, and no thymic tissue is located in the normal position in the mediastinum. The presence of accessory thymic tissue reflects a failed migration of the whole thymic primordia from the third pharyngeal pouches. It may be found at any level of the pathway of normal thymic descent, from the angle of the mandible to the superior mediastinum. The prevalence of foci of accessory thymic tissue varies according to several authors from 1.8% up to more than 50%. A great controversy about the terms being used in the classification of thymic anomalies arises in current literature. Most of the recent articles use the term “ectopic thymus” in a confusing way, because they call cervical extension of the thymus, accessory cervical lobes of the thymus or accessory thymic tissue also “ectopic thymus”. The “genuine” ectopic thymus is a distinct entity from accessory thymic tissue localized in the neck. The term “ectopic thymus” should be reserved for states where only ectopic thymic tissue is present, while no thymus tissue is localized in the normal, mediastinal position. These two entities are differentiated also according to the recommendation of the Terminologia Embryologica (ectopia thymi versus textus thymicus accessorius). A cystic version of accessory thymic tissue localized in the neck is called “congenital cervical thymic cyst”. The cystic version of aberrant thymic tissue is more often described in the literature than the “classical” solid form. Thymopharyngeal duct cyst is another special and extremely rare variant of cystic accessory thymic tissue. Only circa 5 cases are described in the literature. Relatively common and asymptomatic anatomical variation is the fusion of thymus with one or more parathyroid glands - much common with the inferior due to common embryonic origin of both organs. Key-words: accessory thymic tissue, DiGeorge syndrome, ectopic thymus, embryonic development, human thymus, Terminologia Embryologica

• MeSH
• cysty mediastina * diagnóza   klasifikace   vrozené   MeSH
• dítě MeSH
• hyperplazie thymu * diagnóza   klasifikace   vrozené   MeSH
• klasifikace * MeSH
• lidé MeSH
• nádory brzlíku * diagnóza   klasifikace   vrozené   MeSH
• thymus * abnormality   anatomie a histologie   růst a vývoj   MeSH
• vrozené, dědičné a novorozenecké nemoci a abnormality MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• přehledy MeSH

A thorough understanding of the anatomy, physiology, and development of the spleen is essential for determining the pathophysiological mechanisms underpinning splenic diseases and congenital variations. The aim of this review is to briefly summarize current knowledge regarding the normal development of the spleen, and to provide an overview of clinically relevant congenital splenic variations. These include such variations as asplenia, polysplenia, hyposplenia, lobulation of spleen, accessory spleens, accessory splenic nodules, wandering spleen, splenogonadal and splenopancreatic fusion, splenic cysts, and cavernous haemangioma of the spleen. All of these congenital variations are also mentioned in internationally accepted embryological nomenclature, known as the Terminologia Embryologica. Interestingly, most patients who have these diseases are asymptomatic, and are often diagnosed only after an injury or during unrelated medical procedures. Using examples from published case reports, we highlight how an understanding of the embryology of the spleen and the etiology of its disease states would improve clinical practice.

• MeSH
• abnormality lymfatického systému patologie   MeSH
• anatomická variace * MeSH
• lidé MeSH
• slezina embryologie   patologie   MeSH
• terminologie jako téma MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH