Glossary - T

Tay-Sachs Disease

Tay-Sachs Disease, also called Amaurotic Familial Idiocy, it is a hereditary metabolic disorder causing progressive mental and neurologic deterioration resulting in death in early childhood. The disease is caused by a recessive genetic trait, occurs most commonly among people of Eastern European Jewish origin, and can be detected by prenatal tests. Abnormally low activity of the enzyme hexosaminidase A allows an unusual sphingolipid to accumulate in the brain. In some affected children, the enzyme is present but the sphingolipid accumulates nonetheless. Tay-Sachs children appear normal at birth but become listless and inattentive during the first few months of life. As the disease progresses, the child loses motor abilities already gained, such as crawling and sitting and eventually is unable even to raise its head. A cherry-red spot develops on the retina, and blindness and a general paralysis usually precede death.

Testicular Malignancies

Testicular Malignancies is a condition involving primary testicular neoplasms that arise from any testicular or adnexal cell component. They are divided into germinal(90-95%) and non-germinal tumors. The germinal tumors are further divided into seminomatous and non-seminomatous types (embryonal, teratoma, choriocarcinomas and the yolk sac).

Clinical Staging

A-tumor limited to testes and cord

B-tumor of testes and retroperitoneal nodes

B1-nodes less than 2 cm.

B2-positive retroperitoneal nodes 2-6 cm. in diameter

B3-positive retroperitoneal nodes >6 cm. in diameter

C-metastases above diaphragm or involving abdominal solid organs

Testicular malignancies affect the reproductive system. There is no solid evidence if genetic familial connection. The incidence/prevalence in the United States is 1-2% of all neoplasms in male; 2.3-6.3 cases/year per 100,000 men; in adults, germ cell types comprise 90-95% of testicular cancers and in children, they represent only 60-75%. Peak incidence occurs between the ages of 20 to 40 with smaller peaks from 0 to 10 and >60. Signs and symptoms in adults include:scrotal nodule or swelling most common; sensation of fullness or heaviness of the scrotum (may be interpreted as pain); previously small testicle enlarging to the size of "normal" contralateral one; firm non-tender mass within confines of tunica albuginea usually palpably distinct from cord structures; acute or chronic epididymitis/epididymo-orchitis resulting in delay of diagnosis; manifestations due to metastasis eg. neck mass(supraclavicular node), respiratory symptoms (lung metastasis), low back pain (nerve root or psoas irritation), uni- or bilateral lower extremity swelling (iliac or caval thrombosis or obstruction) palpable abdominal mass; hydrocele; gynecomastia; rapid tumor growth resulting in hemorrhage and necrosis. Signs and symptoms inn children are; non-tender, non-painful scrotal mass; non-transilluminable, large, tender testicle; hydrocele; with hormonally active tumors, the scrotal exam may be unrevealing. There are no real clear cause and effect relations identified for this condition. People of the caucasian race (esp. Scandinavian), a higher social status, and a rural resident are at higher risk. The only undisputed risk factor is history of cryptorchism (even if previously prepared). There are some weak associations with; maternal; ingestion of hormones during first trimester, intersex disorders in genotypic male with dysgenetic gonad and trauma.

Thalassemia

Thalassemia is a group of inherited disorders that affect the synthesis of hemoglobin.In beta-thalassemia, there is deficient synthesis of beta globin, while in alpha-thalassemia, there is deficient synthesis of alpha globin. this leads to deficient hemoglobin accumulation, resulting in hypochromic and microcytic red cells. Abnormality of the red cells is the most characteristic feature of the thalassemias. Thalassemia is prevalent in the Mediterranean region, Middle East and South East Asia, and among ethnic groups originating from these areas.

Thalassemia is inherited in an autosomal recessive pattern. Inheriting one defective gene will lead to a milder type of thalassemia while inheriting two defective genes will lead to a severe type of thalassemia. There are approximately 1000 patients in the United States with severe thalassemia. The incidence of thalassemia trait within the ethnic groups involved ranges from 3-5%. Symptoms of the condition start to appear 3-6 months after birth. There is no predominant sex affected by this disease. Signs and symptoms of thalassemia are; pallor; poor growth; inadequate food intake; fatigue; shortness of breath; splenomegaly; jaundice; leg ulcers; cholelithiasis; and pathologic fractures. Thalassemia is caused by genetic factors and those at the greatest risk are people with a family history of thalassemia.

Forms:

1. Beta-thalassemia major (Cooly's anemia)-severe anemia growth retardation, hepatosplenomegaly, bone marrow expansion and bone deformities. Transfusion therapy is necessary to sustain life.

2. Thalassemia intermedia-milder form of thalassemia. Transfusion therapy may not be needed.

3. Thalassemia trait (alpha or beta)-mild anemia with microcytosis and hypochromia. No transfusion therapy is needed.

Thromboangiitis obliterans

Thromboangiitis obliterans (Buerger's disease) is an occlusion of small and medium sized arteries and veins caused by inflammatory changes of these vessels. It primarily occurs in men who smoke. This disease affects the cardiovascular system. Genetically, there is a greater prevalence of HLA-A9 and HLA-B5. Familial cases are rarely reported. The incidence of this condition in the United States is 13/100,000. The predominant age is 20 to 40 years old. The disease primarily affects men more than women by a ratio of 3:1 although increasing numbers of women are being diagnosed, presumably to increased smoking.Symptoms tend to wax and wane in early disease and are often asymmetric. Symptoms may be gradual or have a sudden onset related to impaired vasculature. The symptoms include; ulceration of digits, pain may be disabling; coldness in feet and/or fingers; cold sensitivity; paresthesias (numbness, tingling, burning, hypesthesia) of feet and/or fingers; intermittent claudication in arch of foot or leg (rarely hand, forearm); persistent extremity pain (may be worse at rest);paroxysmal "electric shock" pain of ischemic neuropathy; Raynaud's phenomenon; postural color changes (pallor on elevation and rubor on dependency); Buerger's color i.e., cyanosis on hands and feet; migratory superficial phlebitis; tender skin nodules on extremities; impaired distal pulses (proximal pulses normal); foot edema; and gangrene. Postulated causes are; smoking, genetic factors and an auto immune disorder with cell mediated sensitivity to types I and III human collagens (both are constituents of blood vessels). People who smoke and people from Israel, Eastern Europe, Japan, India and the Far East are at a greater risk of being diagnosed with this disease.

Thyroid malignant neoplasia

Thyroid malignant neoplasia is an autologous growth of thyroid nodules with potential for metastases. Thyroid malignant neoplasia affects the endocrine and metabolic systems. Genetically, in medullary carcinoma, autosomal is dominant with MEN syndrome. In the U.S. the incidence is 0.0051/100,000 with 10,500 new cases per year. The predominant age of people diagnosed with this condition is over 40 years of age and the predominant sex is female over male, by a ratio of 2.6:1. Signs and symptoms include:painless hard fixed neck mass (in advances cases otherwise soft to hard masses; hoarseness; dysphagia; cervical lymphadenopathy; and dyspnea. The causes of this condition are unknown. The risk factors are; neck irradiation (papillary carcinoma; iodine deficiency (follicular carcinoma; MEN syndrome (medullary carcinoma; and a previous history of less than a total thyroidectomy for malignancy (anaplastic carcinoma.

Papillary carcinoma-most common variety, 60-70% of thyroid tumors. May be associated with radiation exposure. Tumor contains psammoma bodies. Metastasizes by lymphatic route.

Follicular carcinoma-10-20% of thyroid tumors. The incidence has been decreasing since the addition of dietary iodine. It occurs usually in females over 40 years of age. Metastasizes by the hematogenous route.

Hurthle cell carcinoma-usually in patients over 60 years of age. Radioresistant. composed of distinct large eosinophilic cells with abundant cytoplasmic mitochondria.

Medullary carcinoma-arises from perifollicular cells, C-cells.2-5% of all thyroid tumors. Associated with multiple endocrine neoplasia (MEN) syndromes which can be familial or sporadic. Calcitonin is a chemical marker.

Anaplastic carcinoma-3% of thyroid tumors, usually in patients over 60 years of age.

Other-lymphoma sarcoma, or metastatic (renal, breast or lung).

Tourette's syndrome

Tourette's syndrome-Gilles de la Tourette's syndrome is a hereditary chronic neuromuscular disorder consisting of various motor and vocal tics. Tics are sudden, involuntary, brief, repetitive, stereotypic motor movements. Symptoms begin in childhood and the location, number, frequency and complexity of tics change over time. Tourette's syndrome affects the nervous system. There exists a genetic predisposition, frequent familial history of tic disorders. Thought to be autosomal dominant with incomplete and sex-specific penetrances. Tourette's is concordant in identical twins and is discordant in fraternal twins. The incidence in the United States is 0.1 to 0.5 cases per 1,000. It is estimated that there are one million sufferers of Tourette's in the U.S. Tourette's is 3 times more frequent in males than in females. The predominant age for this condition is 2-15 years-old in 95% of cases and the average age is 6-years-old. Signs and symptoms of Tourette's include; tics occurring many times throughout the day and changing over time (may only have one tic at a time);multiple motor tics such as facial grimacing, blinking, head or neck twitching, tongue protruding, sniffing and touching; vocal tics such as grunts, snorts, throat clearing or barking and more complex vocal tics with echolalia (repeating last words of someone else), palilalia (repeating one's own words), coprolalia (use of obscenities) copraxia, or copropraxia (use of obscene gestures); tics usually worsen with stress and are most severe in the day and infrequent with sleep(when absorbed in physical activity the tics are less severe or abate; tics may persist for a few months and remiss then reoccur with a new motor tic. A possible cause of Tourette's is a gene defect that results in variable phenotypic expressions including Tourette's and chronic tic disorder, and obsessive-compulsive disorders. Possible pathology in the basal ganglia is suspected. Dopamine hypothesis suggests enhanced dopamine neurotransmitter within the striatum may be the cause. Risk factors are an increase of prevalence in family members, often undiagnosed. Studies reveal 15 to 80% of patients have a family history.

Tuberculosis

Tuberculosis comes in both chronic and acute form. It is a communicable disease that is caused by the Mycobacterium tuberculosis and is characterized pathologically by inflammatory infiltrations, tubercle formation, caseation, fibrosis and calcification. It usually affects the respiratory system, but may also involve gastrointestinal and genitourinary tracts, bones, and joints. The nervous system along with the skin and lymphatics may also be affected. The disease may enter the body either through inhalation, ingestion, or direct inoculation. An estimated 4.4/100000 cases result in death. It has a higher frequency among males over the age of forty. The reaction of a tissue to infection with the tubercle bacillus may vary morphologically from tubercle formation to a diffuse inflammatory exudation. The tubercle formation is characterized in appearance and composed of a collection of giant cells, epithelioid cells and lymphocytes. In the exudative phase some of the inflammatory products may be removed.

 

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