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Klinefelter's Syndrome

Klinefelter's syndrome is a condition caused by a chromosome nondisjunction in males; affected individuals have a pair of X sex chromosomes instead of just one. It is named after Dr. Harry Klinefelter, a medical researcher at Massachusetts General Hospital, Boston, Massachusetts, who first described this condition in 1942, and is associated with additional risk for some medical conditions. more...

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Cause

The XXY chromosome arrangement is one of the most common genetic variations from the XY karyotype, occurring in about 1 in 1,000 male births. Because of the extra chromosome, individuals with the condition are usually referred to as "XXY Males", or "47,XXY Males" rather than as "suffering from Klinefelter's syndrome."

In mammals with more than one X chromosome, the genes on all but one X chromosome are barred from being expressed. This happens in XXY males as well as XX females. A few genes, however, have corresponding genes on the Y chromosome and are not barred. These triploid genes in XXY males may be responsible for symptoms associated with Klinefelter's syndrome.

Signs and symptoms

XXY males are almost always infertile, and some degree of language impairment may be present. In adults, possible characteristics vary widely and include little to no signs of affectedness, a lanky, youthful build and facial appearance, or a rounded body type with some degree of gynecomastia (increased male breast tissue). Gynecomastia to some extent is present in about a third of individuals affected, a higher percentage than in the XY population. The far end of the spectrum is also associated with an increased risk of breast cancer, pulmonary disease, varicose veins, and osteoporosis, risks shared with women.

Rare X-linked recessive problems occur even more infrequently in XXY males, since these conditions are transmitted by genes on the X chromosome, and people with two X chromosomes are typically carriers rather than affected.

There are many variances within the XXY, (otherwise known as 47,XXY) population, just like in the 46,XY population. While it is possible to characterise 47,XXY males with certain body types, that in itself should not be the method of identification as to whether someone has 47,XXY or not. The only method of identification is karyotype testing.

The condition was identified in 1942 by Klinefelter in Boston. The cause was not found until the 1950s.

Treatment

The condition is irreversible, but its symptoms can be altered in a number of ways, including testosterone treatment and other therapies.

While the gender identity of people with XXY karyotype is generally stable, the number of people with gender identity disorder among the whole seems to be higher than could statistically be expected if those cases were indeed, as the current medical opinion assesses, mere coincidences of people having both gender identity disorder and Klinefelter's independently from each other. The observation on gender identity is based on the reports of support groups for transgender and transsexual people; no scientific study on this subject has been done. The fact that a person undergoing treatment for gender identity disorder has Klinefelter's syndrome is often missed, or the patient is not told, although in many jurisdictions this additional diagnosis can have legal consequences, for example regarding name change or medical treatment having to be adapted.

Read more at Wikipedia.org


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Primary mediastinal yolk SAC tumor in a 45-year-old man
From CHEST, 10/1/05 by Salim S. Harianawala

INTRODUCTION: Extragonadal germ cell tumors (EGCT) account for 10% to 15% of all primary mediastinal tumors. Approximately 12% of mediastinal EGCT are yolk sac tumors (YST). We report a case of mediastinal YST that was initially misdiagnosed as non-small cell lung carcinoma (NSCLC), with detrimental consequences.

CASE PRESENTATION: 45-year-old male smoker was diagnosed, by CT-guided fine needle aspiration (FNA), to have NSCLC invading the mediastinum. He was transferred to our institution for further management two weeks later. Within 24 hours of admission, he developed septic shock requiring mechanical ventilation, vasopressors and broad-spectrum antibiotics. CT scan of chest revealed a mass in the right upper lobe invading the mediastinum and encasing the superior vena cava (SVC). The patient developed SVC syndrome and an SVC stent was placed. Due to the rapid progression of the tumor, a repeat CT-guided FNA was performed on clay 9 of admission. Repeat scrotal examination was normal, and alpha-fetoprotein and beta-HCG levels were sent. The patient went into cardiac arrest the next day and ACLS protocols were unsuccessful. The initial pathology report of the repeat FNA was undifferentiated NSCLC. However, additional immunohistochemical stains were performed postmortem when his alpha-fetoprotein level was reported as 24,305ng/ml. The tumor cells were found to express cytokeratin, alpha-fetoprotein and placental alkaline phosphatase, but were negative for CK7, CK20, TTF-1, CD30, EMA and beta-HCG. This immunohistochemical profile is consistent with yolk sac tumor.

DISCUSSIONS: Probably, the first report of a mediastinal YST was by Teilmann in 1967. With a few exceptions, mediastinal YST appears to be restricted to males and usually presents in the second or third decades of life. At the time of diagnosis, almost 90% of the patients are symptomatic. The common symptoms include chest pain, shortness of breath, weight loss, chills and fever, and SVC syndrome. Over 85% of patients have extension of the tumor outside the mediastinum at diagnosis. Conditions associated with YST include Klinefelter's syndrome and hematologic malignancies. The presence of the latter generally indicates a worse prognosis. The diagnosis of EGCT should be considered in young males who present with a mediastinal mass and have elevated levels of alpha-fetoprotein or beta-HCG. The histology of mediastinal YST displays the same wide spectrum of patterns as seen in the gonads, with the reticular pattern being the most common. Immunohistochemical staining helps differentiate YST from other germ cell tumors. YST usually stains positive for cytokemtin and alpha-fetopretein, negative for Ki-1 and beta-HCG, and may be positive or negative for placental alkaline phosphatase. Mistaking mediastinal EGCT for undifferentiated NSCLC has been reported previously l. In this patient, the initial erroneous diagnosis was, in part, due to the small yield from the initial FNA resulting inability to run the usual immunohistochemical markers for NSCLC. In the past, long-term survival was rare in patients with nonseminomatous EGCT. Incorporation of cisplatin-based chemotherapy has improved survival in these patients, with reported remission rates of 40% to 50% in most series, usually irrespective of histologic subtypes. Patients with residual mediastinal mass but normal serum tumor markers require complete surgical resection. Recurrent disease does not respond well to salvage chemotherapy.

CONCLUSION: When faced with a rapidly progressing mediastinal mass a high degree of suspicion is necessary so as not to miss the diagnosis of EGCT. These tumors carry a better prognosis with chemotherapy than advanced NSCLC, emphasizing the importance of making this distinction. Our case highlights the difficulties that may be encountered in establishing the correct diagnosis.

DISCLOSURE: Salim Harianawala, None.

REFERENCE:

(1) Richardson RL, Schoumacher RA, Fer MF, et al. The unrecognized extra gonadal germ cell cancer syndrome. Ann Intern Med 1981; 94:181-6.

Salim S. Harianawala MD * Vinay K. Sharma MBBS Alan D. Haber MD The Graduate Hospital, Philadelphia, PA

COPYRIGHT 2005 American College of Chest Physicians
COPYRIGHT 2005 Gale Group

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