From Big Medical Encyclopedia

DERMOID (Greek derma skin + oidos look; synonym: dermoid cyst, cystous teratoma, teratoma of skin type) — the cystous education arising at disturbances of an embryogenesis and containing elements of an ectoderm.

Fig. 1. Microscopic picture of a wall of a dermoid cyst: 1 — a channel of a sebaceous gland; 2 — a multilayer flat keratosic epithelium — an internal vystilka of a cyst; 3 — sebaceous glands; x 24.
Fig. 2. The roentgenogram of a thorax in a straight line (1) and the right braid (2) projections of sick e a dermoid cyst of a mediastinum (it is specified by an arrow). The gullet filled with a baric suspension is crushed by a tumor to a backbone (it is specified by two shooters).

Carry some to D. epidermoid cysts (see). Surely contains the fabrics not characteristic of this area and not formed in the course of a metaplasia of local fabric elements. Usually has roundish, not always the correct form, smooth or slightly chicken skin. Size it from shares of centimeter to the large sizes. A consistence plotnoelastichesky or pasty, heterogeneous on various sites. Happens single-chamber and multichamber, its contents — fat - or the jellylike mass of various density, grayish or brownish color, to balls of hair. Lumps of grease weight consist of desquamated cells of a flat epithelium, crystals of cholesterol and amorphous fat; the wall of a cyst consists of dense connecting fabric with sites of calcification, sometimes contains a cartilaginous or bone tissue. The inner surface often has an appearance of skin and is covered by a multilayer flat epithelium (fig. 1). Also sweat glands, hair bulbs and plentiful vascular network are more deeply located grease. The cysts having an eminence on an inner surface — a so-called head hillock meet. It is dense, covered with skin and may contain elements of all three germinal leaves. In some D. the inner surface on various extent is deprived of an epithelial vystilka, covered a rusty look with imposings. Such D. call abortal or growing old. Its wall is hyalinized here and there, contains limfogistiotsitarny infiltrates, deposits of hemosiderin, crystals of cholesterol, the centers of a xanthomatosis. Loss of an epithelial vystilka, edge is replaced with granulyatsionny fabric, considerably complicates diagnosis. Arises more often in places of merge and overgrowing of embryonal furrows and cavities where the folds of epidermis going deep into are formed. D. in various parts of a body, but most often in the head, a front mediastinum and ovaries, in an abdominal wall, in the thickness of retroperitoneal and pelvic cellulose meets, is more rare in a liver, kidneys, a brain and its covers. At localization on open parts of a body of D. are found at young age. Located in cellulose of belly and pelvic area in a chest cavity, come to light late, sometimes are followed by pain.

Clinical manifestations Depend on its arrangement and the sizes, and also extent of dysfunction of the next bodies. At D.'s breakthrough in the next cavities or its contents can be allocated for the surface of skin. Long pressure of D. upon bones causes their atrophy, pressure upon adjacent bodies can be followed by symptoms of their prelum. Dermoid cysts sometimes suppurate, legs of dermoid oothecomas can be overwound and come off.

Rentgenol, a research (roentgenoscopy, a X-ray analysis, a tomography and other special techniques) represents a reliable way of identification of. By means of a X-ray analysis the deepenings and defects in bones of a skull caused by thinning of a bone from pressure of are found. Contours of defect are smooth and accurate, with the condensed border on edge. Of presakralny space can cause regional defect of a front wall of a sacrum and a deviation of a tailbone of a kzada. At D.'s arrangement in a mediastinum gives the fullest information pnevmomediastinografiya (see) in combination with tomography (see). Is usually presented in the form of a homogeneous ovoidny shadow in upper or average part of a mediastinum (fig. 2). Its lateral contours, speakers are more often to the right pulmonary field, volnist are usually smooth or slightly; medial merge with a shadow of a mediastinum, and at big D. they can act also to the left of it. Calcification of a wall of D. is quite often noted, bone inclusions, teeth can be found. Unlike coelomic and parasitic cysts D.'s configuration does not change depending on breath and a natuzhivaniya.

There is no active pulsation of a wall. Belly and pelvic cavities helps with D.'s recognition Pneumoretroperitoneum (see) and pneumoperitoneum (see).

Treatment only operational. A recurrence is rare. In most cases — the high-quality, slowly growing educations. In 5 — 8% of cases there is a malignancy of one of fabric components D.: at the same time planocellular cancer most often develops.

See also Teratoma .

Bibliography: Clinical oncology, under the editorship of H. N. Blochina and B. E. Peterson, t. 2, page 58, 353, M., 1971; The Multivolume guide to surgery, under the editorship of B. V. Petrovsky, t. 6, book 2, page 38, M., 1966; Ovnatanyank. T. and Kravets V. M. Tumors and cysts of a mediastinum (including pathology of a thymus), Kiev, 1971, bibliogr.; Petrovsky B. V. Hirurgiya of a mediastinum, M., 1960, bibliogr.

B. A. Rudyavsky.