ALLOTOPIA (dystopia; Greek dys-+ topos place; synonym allotopia) — moving of separate cells, fabrics or bodies to the place, unusual to them.
Most often D. arises in the early embryonal period and is a consequence patol, differentiations of fetal egg. Can arise vneutrobno, in the course of the subsequent development, be a consequence of injuries or surgical manipulations.
An example of cellular D. — detection of separate pear-shaped neurocytes (Purkinye's cells) of a cerebellum in a granular layer of bark, unusual to them, or separate nervous cells — among nerve fibrils of lateral columns or roots of a spinal cord.
Fabric D. meets more often. It endometriosis of bodies, cases of finds of a cartilage or bone in fabric of an almond, a small egg, an ovary can be an example; tissues of a pancreas — in walls of a stomach, mucous membrane of a stomach — in a gullet, intestines, etc. Fabric D. should be differentiated with a heterotopic osteogenesis (see. Bone, pathological anatomy ) and metaplasia (see) of which development of these or those fabrics in the place unusual for them is also characteristic.
Of bodies can arise because of a dizembriogenez, e.g. the return arrangement of bodies at situs viscerum inversus (see Transpozition of bodies), various shifts of bodies of an urogenital sine: most often it is about the shift of kidneys (or one kidney) to the area of a basin, is more rare a chest cavity (a thoracic kidney), a small egg under skin of a crotch, both testicles in one half of a scrotum. After a pneumonectomy there is a shift of bodies of a mediastinum towards the absent lung.
Of bodies can be followed by signs of their functional insufficiency and then is subject to operational correction. Of cells and fabrics, as a rule, proceeds asymptomatically, however can be a source of development of teratogenic tumors.
N. K. Permyakov.