Book 4 - Self Instructional Manual for Cancer Registrars - SEER ...

Parathyroid GlandThere are four parathyroidglandslocatedimmediatelybehindthe thyroidglandbeneathitsoutercapsule. There is, however, little correlation between the functions of the thyroid and theparathyroids. Although each parathyroid is only about the sizeof a grain of rice, its function isessentialto life.The chief cells of the parathyroid secrete a hormone, parathormone, which maintains the normalphosphorous and calcium levels in the body. Parathormone controls the excretion of phosphorus inthe kidney and also mobilizes calcium and phosphorus in bone. It also increases the absorption ofcalcium from the intestinal tract when necessary.An excess of parathormone may cause Recklinghausen's disease of the bone (osteitis fibrosacystica). Excessive parathormone draws calcium from the bone and raises this level in the blood.Pathological fractures may result.Tumors of the parathyroid are extremely rare; most are benign adenomas.Pineal GlandThe pineal gland (epiphysis) is located in the brain attached to the roof of the third ventricle(epithalamus). It secretes the hormone melatonin, which contributes to the process of skinpigmentation, and is thought to secrete serotonin and adrenoglomerulotropin. Although its truefunctions remain a mystery, it is also believed to serve as a "biological clock."Tumors of the pineal gland are called pinealomas and are usually benign. Since these tumors arelocated in the brain, you may be requested to include them in the registry together with benign braintumors.Figure 54. THYROID ANDPARATHYROID GLANDSFigure 55. PINEAL GLAND7h_lL_su_%_ / _ ".... i . . ", _ , . ... ; . .'_i' / ..!\..._!_!:'";_..,,:_.a.;,:.......... ",'_'T__-'----_f ..... _t..,_. / _ _j_-t/332