Timoma – heterogeneous group of new growths, various on a histogenesis and degree of a maturity, originating from epitelialny tissue of a thymus. Options of a clinical current of a timoma can be various: from asymptomatic to expressed (a compression, pain, miastenichesky, intoksikatsionny syndrome). The Topografo-anatomichesky and etiologichesky diagnosis is established by means of beam methods (a X-ray analysis, sredosteniye KT), a transthoracic puncture, a mediastinoskopiya, a research of a bioptat. Treatment is surgical: the removal of a timoma together with a thymus and fatty cellulose of a forward sredosteniye added according to indications with himioluchevy therapy.
Timoma – the organospetsifichesky tumor of a sredosteniye coming from cellular elements of brain and cortical substance of a timus. The term "timom" was put into practice in 1900 by researchers of Grandhomme and Scminke for designation of various tumors of a thymus. Timoma make 10-20% of all new growths of mediastinalny space. In 65-70% of cases of a timoma have a good-quality current; invasive growth with germination of a pleura and a pericardium is noted at 30% of patients, the remote metastasis – at 5%. Slightly more often timoma develop at women, persons of 40-60 years are ill mainly. Less than 8% of tumors of a timus are the share of children's age.
The reasons of formation of tumors of a thymus are unknown. It is supposed that timoma can have an embryonic origin, to be connected with violation of synthesis of a timopoetin or immune homeostasis. As the factors provoking growth and development of a tumor infectious diseases, radiative effects, sredosteniye injuries can serve. It is noticed that timoma are often combined with various endocrine and autoimmune syndromes (a myasthenia, dermatomiozity, hard currency, a diffusion toxic craw, Itsenko-Cushing's syndrome, etc.).
Structure and functions of a thymus
The thymus, or settles down in the lower part of a neck and forward department of the top sredosteniye. The body is formed by two asymmetric shares – right and left. In turn, each share is presented by a set of the segments consisting of cortical and brain substance and concluded in soyedinitelnotkanny to Strom. In a thymus distinguish two types of fabric – epitelialny and lymphoid. Epitelialny cages sekretirut timichesky hormones (, a-, b-timoziny, timopoetina and so forth), lymphoid fabric consists of T-lymphocytes of various degree of a maturity and functional activity.
Thus, the thymus at the same time is an endocrine gland and the body of immunity providing interaction of endocrine and immune systems. After 20 years is exposed to age involution; after 50 years the parenchyma of a timus for 90% is replaced with fatty and connecting tissue, remaining in the form of the separate islands lying in sredosteniye cellulose.
Classification of a timoma
In oncology distinguish three types Tim: a good-quality, malignant timoma of the 1st type (with atipiya signs, but rather good-quality current) and a malignant timoma of the 2nd type (with invasive growth).
The good-quality timoma (50-70% of tumors of a timus) macroscopically has an appearance of the single encapsulated knot, with a diameter no more than 5 cm. Taking into account a histogenesis in this group allocate medullary (type A), mixed (AV type) and mainly kortikalny (B1 type) to timy.
Timoma of type A (medullary) makes 4–7% of benign tumors of a thymus. Depending on a structure can be solid and veretenokletochnoy-krupnokletochny, practically always has the capsule. The forecast is favorable, 15-year survival makes 100%.
Timoma of the AV type (kortiko-medullary) occurs at 28–34% of patients. Combines the centers of a kortikalny and medullary differentiation. Has the satisfactory forecast; 15-year survival – more than 90%.
Timoma of the B1 type (mainly kortikalny) meets in 9–20% of cases. Often has the expressed lymphocytic infiltration. More than at a half of patients is followed by a miastenichesky syndrome. The forecast is satisfactory; 20-year survival - more than 90%.
The malignant timoma of the 1st type (20-25% of cases) represents single or multiple lobular knots without accurate capsule. The tumor size does not exceed 4-5 cm more often, however new growths of the big sizes sometimes meet. Differs in invasive growth within gland. In the histologic relation it is presented kortikalny timomy (B2 type) and the high-differentiated carcinoma.
Timoma of the B2 type (kortikalny) makes about 20-36% Tim. Histologic versions are variable: dark-cellular, light-cellular, watery and cellular, etc. In most cases proceeds with a myasthenia. Predictively is less favorable: 20 years live less than 60% of patients.
Timoma of the B3 type (epitelialny) develops at 10–14% of patients. Often has hormonal activity. The forecast is worse, than at a kortikalny version; 20-year survival less than 40%.
The malignant timoma of the 2nd type (cancer of a timus, timom of type C) makes up to 5% of all observations. Differs in the expressed invasive growth, high metastatic activity (gives metastasises in a pleura, lungs, a pericardium, a liver, bones, adrenal glands). Allocate 6 histologic types of cancer of a timus: planocellular, veretenokletochny, light-cellular, limfoepitelialny, undifferentiated, mukoepidermoidny.
Depending on the specific weight of a lymphoid component in a timoma differentiate lymphoid (more than 2/3 all cells of a tumor are presented by T-lymphocytes), limfoepitelialny (T-lymphocytes make from 2/3 to 1/3 cages) and epitelialny timoma (T-lymphocytes presented less than 1/3 all cages).
Based on extent of invasive growth, allocate 4 stages of a timoma:
The I stage - the encapsulated timoma without germination of fatty cellulose of a sredosteniye
The II stage – germination of elements of a tumor in mediastinalny cellulose
The III stage - an invasion of a pleura, lung, a pericardium, large vessels
The IV stage – existence of implantation, hematogenic or limfogenny metastasises.
Clinical manifestations and current of a timoma depends on its type, hormonal activity, the sizes. More than in half of cases the tumor develops latentno and it is found during the preventive radiological research.
Invasive timoma cause a compression mediastinalny syndrome which is followed by pains behind a breast, dry cough, short wind. Sdavleny tracheas and large bronchial tubes it is shown by a stridor, cyanosis, respiratory insufficiency. At a syndrome of a compression of the top hollow vein there is puffiness of the person, cyanosis of the top half of a trunk, swelling of cervical veins. Pressure of the growing tumor upon nerve ganglions causes development of a syndrome of Horner, a voice osiplost, a diaphragm dome elevation. Squeezing of a gullet is followed by disorder of swallowing – a dysphagy.
According to various data, from 10 to 40% are combined by Tim with a miastenichesky syndrome. Patients note decrease in muscular force, bystry fatigue, weakness of mimic muscles, doubling in eyes, a poperkhivaniye, violations of a voice. In hard cases the miastenichesky crisis demanding transition to IVL and probe food can develop.
In late stages of a malignant timoma symptoms of cancer intoxication appear: fever, anorexia, decrease in body weight. Quite often the timoma is accompanied by various hematologic and immunodeficient syndromes: aplastic anemia, trombotsitopenichesky purple, gipogammaglobulinemiya.
Diagnostics of a timoma
Diagnostics of a timoma is carried out by thoracic surgeons with involvement of oncologists, radiologists, endocrinologists, neurologists. At clinical examination expansion of veins of a thorax, vybukhany breasts in a tumor projection can come to light; increase in cervical, supraclavicular, subclavial lymph nodes; signs of a compression syndrome and myasthenia. The Fizikalny research finds expansion of borders of a sredosteniye, tachycardia, the whistling rattles.
On the roentgenogram of a thorax of a timom has an appearance of the volume formation of irregular shape located in a forward sredosteniye. Thorax KT considerably expands information volume received at primary rentgendiagnostika and in some cases allows to make the morphological diagnosis. Specification of localization and relationship of a new growth with the next bodies at KT sredosteniye allows to execute further a transthoracic puncture of a tumor of a sredosteniye that is extremely important for histologic confirmation of the diagnosis and verification of histologic type of a timoma.
For a visual research of a sredosteniye and performance of a direct biopsy the diagnostic mediastinoskopiya (a parasternalny mediastinotomiya) or a torakoskopiya is carried out. The diagnosis of a myasthenia is specified by means of an electromyography with introduction of antikholinesterazny medicines. Differential and diagnostic actions allow to exclude other volume processes in a sredosteniye: zagrudinny craw, dermoidny cysts and teratoma of a sredosteniye.
Treatment of a timoma
Treatment of tumors of a thymus is carried out in offices of thoracic surgery and oncology. The surgical method is the basic in treatment of a timoma as only the timektomiya provides the satisfactory remote results. At good-quality timoma surgery consists tumors together with a thymus (timomtimektomiya), fatty cellulose and lymph nodes of a sredosteniye at a distance. Such volume of a resection is dictated by high risk of a recurrence of a tumor and a myasthenia. Operation is carried out from median sternotomichesky access.
At malignant new growths of a timus operation can be supplemented with a resection of a lung, a pericardium, the main vessels, a diafragmalny nerve. Postoperative radiation therapy is shown at II and III stages of a timoma. Besides, radiation is the leading method of treatment inoperable malignant Tim IV of a stage. Now bigger value in treatment invasive Tim receives the three-stage treatment including neoadjyuvantny chemotherapy, a resection of a tumor and radiation therapy.
In the postoperative period the patients who transferred a timektomiya can have a miastenichesky crisis which demands performing intensive therapy, a trakheostomiya, IVL, long purpose of antikholinesterazny medicines.
Remote results of treatment good-quality Tim good. After removal of a tumor disappear or considerably myasthenia symptoms decrease. At patients zlokachestyovenny timomy, operated at early stages, 5-year survival reaches 90%, at the III stage – 60-70%. The inoperable forms of an oncological disease are had the bad forecast with a lethality of 90% within the next 5 years.