PATHOLOGY ASSIGNMENT

T.GOWTHAMI

ROLL NO:132

PATHOLOGY ASSIGNMENT

TOPIC:  THYMUS TUMOURS, HYPOTHALAMUS TUMOURS, MALIGNANT ENDOCRINE NEOPLASIA.

THYMUS TUMOURS:

A thymoma is a type of tumour or growth in the thymus gland. Thymic tumors are tumors of the thymus gland.

✓Most thymomas have the potential to behave like a cancer and spread beyond the thymus, but many appear to behave in a benign fashion and are noninvasive.  ✓Less commonly, it appears to have spread beyond the thymus. People sometimes refer to such an invasive thymoma as malignant.

MORPHOLOGIC FEATURES:

✓The tumour is a spherical , measuring 5-10 cms in diameter with an average weight of 150 gm.

✓The tumour  has a thick fibrous capsule from which extend collagenous septa into the tumour dividing it into lobules .

✓The tumour consists of neoplastic epithelial cells and variable number of non-neoplastic lymphocytes.

GENETIC ABNORMALITIES:

✓They are common in thymoma,most commonly affecting chromosome 6.

✓Thymomas are known for their association with paraneoplastic syndrome and they include Myasthenia gravis,Hypogammaglobulinemia, Multiple myeloma etc.

Surgical removal is the mainstay of treatment. Chemotherapy  targeted therapy, and radiation therapy may be used in cases in which surgical treatment is not effective in removing the entire tumor or in particularly aggressive cases.

HYPOTHALAMUS TUMOURS:

 A hypothalamic tumor  is an abnormal growth in the hypothalamus  gland, which is located in the brain.

CAUSES:

✓The exact cause of hypothalamic tumors is not known. It is likely that they result from a combination of genetic and environmental factors.

✓In children, most hypothalamic tumors are gliomas. Gliomas are a common type of brain tumor that results from the abnormal growth of glial cells, which support nerve cells. Gliomas can occur at any age. They are often more aggressive in adults than in children.

✓In adults, tumors in the hypothalamus are more likely cancer that has spread from another organ.

✓People with neurofibromatosis (a hereditary condition) are at increased risk for this type of tumor. People who have undergone radiation therapy are at increased risk of developing tumors in general.

PATHOGENESIS:

There are several types of tumors that occur in this region. Some are unique to the hypothalamus, as they are composed of hypothalamic neurons, but they resemble tumors composed of neurons elsewhere in the brain. Tumors of neural stroma include gliomas but also those derived from the modified special glia known as “pituicytes” of the posterior pituitary. Other lesions that occur in this area are not unique to this location, but are important in the differential diagnosis.

MALIGNANT ENDOCRINE NEOPLASIA:

Multiple endocrine neoplasia is a group of disorders that affect the body's network of hormone-producing glands called the endocrine system.

✓The major forms of multiple endocrine neoplasia are called type 1, type 2, and type 4. These types are distinguished by the genes involved, the types of hormones made, and the characteristic signs and symptoms.

✓Type 1 frequently involves tumors of the parathyroid glands, the pituitary gland, and the pancreas. 

✓Tumors in these glands can lead to the overproduction of hormones. The most common sign of multiple endocrine neoplasia type 1 is overactivity of the parathyroid glands (hyperparathyroidism).

 ✓Hyperparathyroidism disrupts the normal balance of calcium in the blood, which can lead to kidney stones, thinning of bones, nausea and vomiting, high blood pressure , weakness, and fatigue.

✓The most common sign of multiple endocrine neoplasia type 2 is a form of thyroid cancer called medullary thyroid carcinoma. Some people with this disorder also develop a pheochromocytoma, which is an adrenal gland.

✓The tumor that can cause dangerously high blood pressure. Multiple endocrine neoplasia type 2 is divided into three subtypes: type 2A, type 2B (formerly called type 3), and familial medullary thyroid carcinoma . 

✓These subtypes differ in their characteristic signs and symptoms and risk of specific tumors; for example, hyperparathyroidism occurs only in type 2A, and medullary thyroid carcinoma is the only feature of FMTC. 

✓The signs and symptoms of multiple endocrine neoplasia type 2 are relatively consistent within any one family.

✓Multiple endocrine neoplasia type 4 appears to have signs and symptoms similar to those of type 1, although it is caused by mutations in a different gene.

✓ Hyperparathyroidism is the most common feature, followed by tumors of the pituitary gland, additional endocrine glands, and other organs.