118. Tumors of melanin-forming tissue: origin, terminology, types. Macro-microscopic structure, complications, clinical significance.

1) Nevi are tumor-like formations found in the skin, often on the face, in dark-colored bulging formations. They distinguish:

Borderline nevus (at the border of the epidermis and dermis)

Intradermal (it is common, consists of nests and strands of nevus cells, which are located only in the dermis.)

A complex nevus (mixed) has features of both borderline and intradermal nevus.

Epithelioid (occurs on the face mainly in children.) It consists of spindle-shaped, epithelioid, multinucleated giant cells.

Blue nevus occurs in people aged 30-40 years in the dermis, more often in the buttocks and extremities. It has the appearance of a nodule with a bluish tinge, consists of proliferating melanocytes that can grow into subcutaneous tissue.

2. Melanoma is a malignant tumor of melanin-forming tissue, has a pronounced tendency to metastasis. It develops in the skin, the pigment membrane of the eye, the meninges, the medulla of the adrenal glands, rarely in the mucous membranes. It is possible to develop melanoma from nevus. It may look like a brown spot with pink and black inclusions, in the form of a black and blue soft knot. It consists of spindle-shaped ugly cells containing melanin. Sometimes there are pigmented melanomas. There are many mitoses in the tumor, foci of hemorrhages and necrosis are noted. When they disintegrate, large amounts of melanin and promelanin are released into the blood, which can be accompanied by melaninemia and melaninuria. Melanoma produces hematogenous and lymphogenic metastases early.

119. Teratomas: origin, terminology, types. Macro-microscopic structure, complications, clinical significance.

Teratomas are expansively growing tumors consisting of derivatives of three germ leaves with the presence or absence of elements of extraembryonic tissues (trophoblast elements); tumors consisting of many tissues foreign to a given localization

Classification of teratomas:

a) benign: mature and immature

b) malignant

Mature teratomas are benign, highly differentiated tumors, histologically: mature neuroglia, bones, cartilage, hair, hepatocytes, MMC and striated muscles, other mature somatic structures

Immature teratoma – contains incompletely differentiated (immature) somatic structures that reproduce the processes of organogenesis in embryos; histologically: immature neuroectoderm with primitive medulloblast-like cells, neuroblasts and neuroblastoma-like cells, immature epithelial, renal and hepatic tissues, cartilage, primitive mesenchyme, rhabdomyoblasts

Malignant teratoma – the presence of immature tissues and carcinoid-like solid and papillary structures, sarcomatous, cancerous fields; they grow rapidly, metastasize early to the left ear, liver, lungs

Cresciococcygeal teratoma mask: large, encapsulated, clearly delimited, cystic or solid on the incision; cysts contain serous fluid, mucus, cheese-like or flake-like protein masses, rudimentary organs and fetal tissues (teeth, etc.); sometimes foci of calcification

MiSk: in most cases, highly differentiated tissues, the main part of the tumor is ectodermal tissue, the most immature component is primitive neuroectoderm (not an indicator of malignancy)