A thymoma is a tumor originating from the epithelial cells of the thymus that is considered a rare malignancy. Thymomas are frequently associated with neuromuscular disorders such as  myasthenia gravis; thymoma is found in 20% of patients with myasthenia gravis. Once diagnosed, thymomas may be removed surgically. In the rare case of a malignant tumor, chemotherapy may be used. Signs and symptoms
A third of all people with a thymoma have symptoms caused by compression of the surrounding organs by an expansive mass. These problems may take the form of superior vena cava syndrome, dysphagia (difficulty swallowing), cough, or chest pain.One-third of patients have their tumors discovered because they have an associated autoimmune disorder. As mentioned earlier, the most common of those conditions is myasthenia gravis (MG); 10–15% of patients with MG have a thymoma and, conversely, 30–45% of patients with thymomas have MG. Additional associated autoimmune conditions include thymoma-associated multiorgan autoimmunity, pure red cell aplasia and Good syndrome (thymoma with combined immunodeficiency and hypogammaglobulinemia). Other reported disease associations are with acute pericarditis, agranulocytosis, alopecia areata, ulcerative colitis, Cushings disease, hemolytic anemia, limbic encephalopathy, myocarditis, nephrotic syndrome, panhypopituitarism, pernicious anemia, polymyositis, rheumatoid arthritis, sarcoidosis, scleroderma, sensorimotor radiculopathy, stiff person syndrome, systemic lupus erythematosus and thyroiditis.One-third to one-half of all persons with thymoma have no symptoms at all, and the mass is identified on a chest X-ray or CT/CAT scan performed for an unrelated problem. Pathology
Thymoma originates from the epithelial cell population in the thymus, and several microscopic subtypes are now recognized.
A twin study conducted by the Department of Psychology at Oslo University attempted to establish a correlation between genetics and Cluster B personality disorders. With a test sample of 221 twins, 92 monozygotic and 129 dizygotic, researchers interviewed the subjects using the Structured Clinical Interview for DSM-III-R Personality Disorders (SCID-II) and concluded that there was a correlation of 0.67 that histrionic personality disorder is hereditary. Psychoanalytic theory
Though criticised as being unsupported by scientific evidence, psychoanalytic theories incriminate authoritarian or distant attitudes by one (mainly the mother) or both parents, along with conditional love based on expectations the child can never fully meet. Using psychoanalysis, Freud believed that lustfulness was a projection of the patients lack of ability to love unconditionally and develop cognitively to maturity, and that such patients were overall emotionally shallow. He believed the reason for being unable to love could have resulted from a traumatic experience, such as the death of a close relative during childhood or divorce of ones parents, which gave the wrong impression of committed relationships. Exposure to one or multiple traumatic occurrences of a close friend or family members leaving (via abandonment or mortality) would make the person unable to form true and affectionate attachments towards other people. HPD and antisocial personality disorder
Another theory suggests a possible relationship between histrionic personality disorder and antisocial personality disorder.