Hormone secreting pituitary adenomas cause one of several forms of hyperpituitarism. The specifics depend on the type of hormone. Some tumors secrete more than one hormone, the most common combination being GH and prolactin, which present as unexpected bone growth and unexpected lactation (in both men and women).

A patient with pituitary adenoma may present with visual field defects, classically bitemporal hemianopsia. It arises from the compression of the optic nerve by the tumor. The specific area of the visual pathway at which compression by these tumours occurs is at the optic chiasma.

The anatomy of this structure causes pressure on it to produce a defect in the temporal visual field on both sides, a condition called bitemporal hemianopsia. If originating superior to the optic chiasm, more commonly in a craniopharyngioma of the pituitary stalk, the visual field defect will first appear as bitemporal inferior quadrantanopia, if originating inferior to the optic chiasm the visual field defect will first appear as bitemporal superior quadrantanopia. Lateral expansion of a pituitary adenoma can also compress the abducens nerve, causing a lateral rectus palsy.

Also, a pituitary adenoma can cause symptoms of increased intracranial pressure.

Prolactinomas often start to give symptoms especially during pregnancy, when the hormone progesterone increases the tumor's growth rate.

Various types of headaches are common in patients with pituitary adenomas. The adenoma may be the prime causative factor behind the headache or may serve to exacerbate a headache caused by other factors. Amongst the types of headaches experienced are both chronic and episodic migraine, and more uncommonly various unilateral headaches; primary stabbing headache, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) - another type of stabbing headache characterized by short stabs of pain -, cluster headache, and hemicrania continua (HS).

Non-secreting adenomas can go undetected for an extended time because no obvious abnormalities are seen; the gradual reduction in normal activities due to decreased production of hormones is rather less evident. For example, insufficient adrenocorticotropic hormone means that the adrenal glands will not produce sufficient cortisol, resulting in slow recovery from illness, inflammation and chronic fatigue; insufficient growth hormone in children and adolescents leads to diminished stature but which can have many other explanations.

Various psychiatric manifestations have been associated with pituitary disorders including pituitary adenomas. Psychiatric symptoms such as depression, anxiety apathy, emotional instability, easy irritability and hostility have been noted.

An endocrine gland neoplasm is a neoplasm affecting one or more glands of the endocrine system.

Examples include:

- Adrenal tumor

- Pituitary adenoma

The most common form is thyroid cancer.

Condition such as pancreatic cancer or ovarian cancer can be considered endocrine tumors, or classified under other systems.

Pinealoma is often grouped with brain tumors because of its location.

The adrenal cortex is composed of three distinct layers of endocrine cells which produce critical steroid hormones. These include the glucocorticoids which are critical for regulation of blood sugar and the immune system, as well as response to physiological stress, the mineralcorticoid aldosterone, which regulates blood pressure and kidney function, and certain sex hormones. Both benign and malignant tumors of the adrenal cortex may produce steroid hormones, with important clinical consequences.

An adrenal tumor or adrenal mass is any benign or malignant neoplasms of the adrenal gland, several of which are notable for their tendency to overproduce endocrine hormones. Adrenal cancer is the presence of malignant adrenal tumors, and includes neuroblastoma, adrenocortical carcinoma and some adrenal pheochromocytomas. Most adrenal pheochromocytomas and all adrenocortical adenomas are benign tumors, which do not metastasize or invade nearby tissues, but may cause significant health problems by unbalancing hormones.

Almost all thyroid adenomas are follicular adenomas. Follicular adenomas can be described as "cold", "warm" or "hot" depending on their level of function. Histopathologically, follicular adenomas can be classified according to their cellular architecture and relative amounts of cellularity and colloid into the following types:

- Fetal (microfollicular) - these have the potential for microinvasion. These consist of small, closely packed follicles lined with epithelium.

- colloid (macrofollicular) - these do "not" have any potential for microinvasion

- embryonal (atypical) - have the potential for microinvasion.

- Hürthle cell adenoma (oxyphil or oncocytic tumor) - have the potential for microinvasion.

- Hyalinizing trabecular adenoma

Papillary adenomas are very rare.

Pituitary tumors occur in 15 to 42% of MEN 1 patients. From 25 to 90% are prolactinomas. About 25% of pituitary tumors secrete growth hormone or growth hormone and prolactin. Excess prolactin may cause galactorrhea (see Pituitary Disorders: Galactorrhea), and excess growth hormone causes acromegaly clinically indistinguishable from sporadically occurring acromegaly. About 3% of tumors secrete ACTH, producing Cushing's disease. Most of the remainder are nonfunctional. Local tumor expansion may cause visual disturbance, headache, and hypopituitarism. Pituitary tumors in MEN 1 patients appear to be larger and behave more aggressively than sporadic pituitary tumors.

Pancreatic islet cell tumors occur in 60 to 70% of patients. Tumors are usually multicentric. Multiple adenomas or diffuse islet cell hyperplasia commonly occurs; such tumors may arise from the small bowel rather than the pancreas. About 30% of tumors are malignant and have local or distant metastases. Malignant islet cell tumors due to MEN 1 syndrome often have a more benign course than do sporadically occurring malignant islet cell tumors.About 40% of islet cell tumors originate from a β-cell, secrete insulin (insulinoma), and can cause fasting hypoglycemia. β-cell tumors are more common in patients 40 years of age. Non-β-cell tumors are somewhat more likely to be malignant.

Most islet cell tumors secrete pancreatic polypeptide, the clinical significance of which is unknown. Gastrin is secreted by many non–β-cell tumors (increased gastrin secretion in MEN 1 also often originates from the duodenum). Increased gastrin secretion increases gastric acid, which may inactivate pancreatic lipase, leading to diarrhea and steatorrhea. Increased gastrin secretion also leads to peptic ulcers in > 50% of MEN 1 patients. Usually the ulcers are multiple or atypical in location, and often bleed, perforate, or become obstructed. Peptic ulcer disease may be intractable and complicated. Among patients presenting with Zollinger-Ellison syndrome, 20 to 60% have MEN 1.

A severe secretory diarrhea can develop and cause fluid and electrolyte depletion with non–β-cell tumors. This complex, referred to as the watery diarrhea, hypokalemia and achlorhydria syndrome (VIPoma) has been ascribed to vasoactive intestinal polypeptide, although other intestinal hormones or secretagogues (including prostaglandins) may contribute. Hypersecretion of glucagon, somatostatin, chromogranin, or calcitonin, ectopic secretion of ACTH resulting in Cushing's syndrome, and hypersecretion of somatotropin–releasing hormone (causing acromegaly) sometimes occur in non–β-cell tumors. All of these are rare in MEN 1.Nonfunctioning pancreatic tumors also occur in patients with MEN 1 and may be the most common type of pancreatoduodenal tumor in MEN 1. The size of the nonfunctioning tumor correlates with risk of metastasis and death.

A thyroid adenoma may be clinically silent ("cold" or "warm" adenoma), or it may be a functional tumor, producing excessive thyroid hormone ("hot" adenoma). In this case, it may result in symptomatic hyperthyroidism, and may be referred to as a toxic thyroid adenoma.

The major clinical symptom of metastatic medullary thyroid carcinoma is diarrhea; occasionally a patient will have flushing episodes. Both occur particularly with liver metastasis, and either symptom may be the first manifestation of the disease. The flushing that occurs in medullary thyroid carcinoma is indistinguishable from that associated with carcinoid syndrome. In MTC, the flushing, diarrhea, and itching (pruritis) are all caused by elevated levels of calcitonin gene products (calcitonin or calcitonin gene-related peptide). Alternatively, the flushing and diarrhea observed in carcinoid syndrome is caused by elevated levels of circulating serotonin.

Medullary thyroid carcinoma may also produce a thyroid nodule and enlarged cervical lymph nodes.

Sites of spread of medullary thyroid carcinoma include local lymph nodes in the neck, lymph nodes in the central portion of the chest (mediastinum), liver, lung, and bone. Spread to other sites such as skin or brain occurs but is uncommon.

Thyroid adenoma is a benign neoplasm of the thyroid. Thyroid nodules are very common and around 80 percent of adults will have at least one by the time they reach 70 years of age. Approximately 90 to 95 percent of all nodules are found to be benign.

Thyroid cancers are mainly papillary, follicular, medullary or anaplastic thyroid cancer. Most patients are 25 to 65 years of age when first diagnosed; women are more affected than men. Nearly 80 percent of thyroid cancer is papillary and about 15 percent is follicular; both types grow slowly and can be cured if caught early. Medullary thyroid cancer makes up about 3 percent of this cancer. It grows slowly and can be controlled if caught early. Anaplastic is the most deadly and makes up around 2 percent. This type grows quickly and is hard to control. The classification is determined by looking at the sample of cells under a microscope and by which type of thyroid cell is present.

Other thyroid malignancies include thyroid lymphoma, various types of thyroid sarcoma, smooth muscle tumors, teratoma, squamous cell thyroid carcinoma and other rare types of tumors.

Most patients experience moderate to severe hypercalcemia and high parathyroid hormone levels. A large mass in the neck is often seen, and renal and bone abnormalities are common.

A parathyroid neoplasm is a tumor of the parathyroid gland.

Types include:

- Parathyroid adenoma

- Parathyroid carcinoma

Pheochromocytoma (PCC) is a neuroendocrine tumor of the medulla of the adrenal glands (originating in the chromaffin cells), or extra-adrenal chromaffin tissue that failed to involute after birth, that secretes high amounts of catecholamines, mostly norepinephrine, plus epinephrine to a lesser extent. Extra-adrenal paragangliomas (often described as extra-adrenal pheochromocytomas) are closely related, though less common, tumors that originate in the ganglia of the sympathetic nervous system and are named based upon the primary anatomical site of origin. The term is from Greek "phaios" "dark", "chroma" "color", "kytos" "cell", "-oma" "tumor".

Medullary thyroid cancer (MTC) is a form of thyroid carcinoma which originates from the parafollicular cells (C cells), which produce the hormone calcitonin.

Medullary tumors are the third most common of all thyroid cancers. They make up about 3% of all thyroid cancer cases.

Approximately 25% of medullary thyroid cancer is genetic in nature, caused by a mutation in the RET proto-oncogene. This form is classified as familial MTC. When MTC occurs by itself it is termed sporadic MTC. When it coexists with tumors of the parathyroid gland and medullary component of the adrenal glands (pheochromocytoma) it is called multiple endocrine neoplasia type 2 (MEN2).It was first characterized in 1959.

The signs and symptoms of a pheochromocytoma are those of sympathetic nervous system hyperactivity, including:

- Skin sensations

- Flank pain

- Elevated heart rate

- Elevated blood pressure, including paroxysmal (sporadic, episodic) high blood pressure, which sometimes can be more difficult to detect; another clue to the presence of pheochromocytoma is orthostatic hypotension (a fall in systolic blood pressure greater than 20 mmHg or a fall in diastolic blood pressure greater than 10 mmHg upon standing)

- Palpitations

- Anxiety often resembling that of a panic attack

- Diaphoresis (excessive sweating)

- Headaches – most common symptom

- Pallor

- Weight loss

- Localized amyloid deposits found microscopically

- Elevated blood glucose level (due primarily to catecholamine stimulation of lipolysis (breakdown of stored fat) leading to high levels of free fatty acids and the subsequent inhibition of glucose uptake by muscle cells. Further, stimulation of beta-adrenergic receptors leads to glycogenolysis and gluconeogenesis and thus elevation of blood glucose levels).

A pheochromocytoma can also cause resistant arterial hypertension. A pheochromocytoma can be fatal if it causes a hypertensive emergency, that is, severely high blood pressure that impairs one or more organ systems (formerly called "malignant hypertension"). This hypertension is not well controlled with standard blood pressure medications.

Not all patients experience all of the signs and symptoms listed. The most common presentation is headache, excessive sweating, and increased heart rate, with the attack subsiding in less than one hour.

Tumors may grow large, but most are smaller than .

They are classified by histology as benign; however, as with many brain tumors, their treatment can be difficult, and significant morbidities are associated with both the tumor and treatment.

- Headache (obstructive hydrocephalus)

- Hypersomnia

- Myxedema

- post surgical weight gain

- Polydipsia

- Polyuria (diabetes insipidus)

- Vision loss (bitemporal hemianopia)

- Vomiting

- often occurs post treatment

- Growth hormone (GH) insufficiency, caused by the reduction in growth hormone (GH) production. Symptoms include:

- Stunted growth and delayed puberty (in children)

- General fatigue, loss of muscle mass and tone (in adults)

- Pituitary insufficiency

- often occurs to some degree because craniopharyngiomas develop in the area of the pituitary stalk, which can affect the function of the pituitary gland.

- Reduction in prolactin production. This is very uncommon and occurs with severe pituitary insufficiency.

- Large pituitary tumors can paradoxically elevate blood prolactin levels due to the "stalk effect." This elevation occurs as a result of the compression of the pituitary stalk, which interferes with the brain's control of prolactin production.

- In premenopausal women, elevated prolactin can lead to reduction or loss of menstrual periods and/or breast milk production (galactorrhea).

- With stalk effect, prolactin levels are usually only slightly elevated, as opposed to prolactinomas in which the prolactin level is usually very high.

- Diabetes insipidus. This occurs due to the absence of a posterior pituitary hormone called antidiuretic hormone (ADH). Symptoms include:

- Excessive thirst

- Excessive urination

- Adrenal insufficiency. This occurs because of a reduction in ACTH production, a reduction in cortisol. In severe cases, it can be fatal. Symptoms include:

- Fatigue

- Low blood pressure

- Electrolyte abnormalities

Parathyroid carcinoma is a rare malignant neoplasm resulting in parathyroid adenoma to carcinoma progression. It forms in tissues of one or more of the parathyroid glands (four pea-sized glands in the neck that make parathyroid hormone, which helps the body store and use calcium).

It is rare, and much less common than parathyroid adenoma.

It can be difficult to excise.

Salivary gland tumours usually present as a lump or swelling in the affected gland which may or may not have been present for a long time. The lump may be accompanied by symptoms of duct blockage (e.g. xerostomia). Usually, in their early stages it is not possible to distinguish a benign tumour from a malignant one. One of the key differentiating symptoms of a malignant growth is nerve involvement. For example signs of facial nerve damage (e.g facial palsy) are associated with malignant parotid tumours. Facial pain, and paraesthesia are also very often associated with a malignant tumours. Other red flag symptoms which may suggest malignancy and warrant further investigation are fixation of the lump to the overlying skin, ulceration and induration of the mucosa.

Due to the diverse nature of salivary gland tumours, many different terms and classification systems have been used. Perhaps the most widely used currently is that system proposed by the World Health Organization in 2004, which classifies salivary neoplasms as primary or secondary, benign or malignant, and also by tissue of origin. This system defines five broad categories of salivary gland neoplasms:

Benign epithelial tumors

- Pleomorphic adenoma

- Warthin's tumor

- Myoepithelioma

- Basal cell adenoma

- Oncocytoma

- Canalicular adenoma

- Lymphadenoma

- "Sebaceous lymphadenoma"

- "Nonsebaceous lymphadenoma"

- Ductal papilloma

- "Inverted ductal papilloma"

- "Intraductal papilloma"

- "Sialadenoma papilliferum"

- Cystadenoma

- Malignant epithelial tumors

- Acinic cell carcinoma

- Mucoepidermoid carcinoma

- Adenoid cystic carcinoma

- Polymorphous low-grade adenocarcinoma

- Epithelial-myoepithelial carcinoma

- Clear cell carcinoma, not otherwise specified

- Basal cell adenocarcinoma

- Sebaceous carcinoma

- Sebaceous lymphadenocarcinoma

- Cystadenocarcinoma

- Low-grade cribriform cystadenocarcinoma

- Mucinous adenocarcinoma

- Oncocytic carcinoma

- Salivary duct carcinoma

- Salivary duct carcinoma, not otherwise specified

- Adenocarcinoma, not otherwise specified

- Myoepithelial carcinoma

- Carcinoma ex pleomorphic adenoma

- Mammary analogue secretory carcinoma

- Carcinosarcoma

- Metastasizing pleomorphic adenoma

- Squamous cell carcinoma

- Large cell carcinoma

- Lymphoepithelial carcinoma

- Sialoblastoma

- Soft tissue tumors

- Hemangioma

- Hematolymphoid tumors

- Hodgkin lymphoma

- Diffuse large B-cell lymphoma

- Extranodal marginal zone B cell lymphoma

- Secondary tumors (i.e. a tumor which has metastasized to the salivary gland from a distant location)

Others, not included in the WHO classification above, include:

- Intraosseous (central) salivary gland tumors

- Hybrid tumors (i.e. a tumor displaying combined forms of histologic tumor types)

- Hybrid carcinoma

- Others

- Others

- Keratocystoma

- Sialolipoma

Most often the first symptom of thyroid cancer is a nodule in the thyroid region of the neck. However, many adults have small nodules in their thyroids, but typically under 5% of these nodules are found to be cancerous. Sometimes the first sign is an enlarged lymph node. Later symptoms that can be present are pain in the anterior region of the neck and changes in voice due to an involvement of the recurrent laryngeal nerve.

Thyroid cancer is usually found in a euthyroid patient, but symptoms of hyperthyroidism or hypothyroidism may be associated with a large or metastatic well-differentiated tumor.

Thyroid nodules are of particular concern when they are found in those under the age of 20. The presentation of benign nodules at this age is less likely, and thus the potential for malignancy is far greater.

Papillary thyroid cancer gets its name from the among its cells, visible on microscopy. Features include:

- Characteristic Orphan Annie eye nuclear inclusions (nuclei with uniform staining, which appear empty due to powdery chromatin and marginal micronucleoli) and psammoma bodies on light microscopy. The former is useful in identifying the follicular variant of papillary thyroid carcinomas.

- Lymphatic spread is more common than hematogenous spread

- Multifocality is common

- The so-called Lateral Aberrant Thyroid is actually a lymph node metastasis from papillary thyroid carcinoma.

- Papillary microcarcinoma is a subset of papillary thyroid cancer defined as measuring less than or equal to 1 cm. The highest incidence of papillary thyroid microcarcinoma in an autopsy series was reported by Harach et al. in 1985, who found 36 of 101 consecutive autopsies to have an incidental microcarcinoma. Michael Pakdaman et al. report the highest incidence in a retrospective surgical series at 49.9 percent of 860 cases. Management strategies for incidental papillary microcarcinoma on ultrasound (and confirmed on FNAB) range from total thyroidectomy with radioactive iodine ablation to observation alone. Harach et al. suggest using the term "occult papillary tumor" to avoid giving patients distress over having cancer. It was Woolner et al. who first arbitrarily coined the term "occult papillary carcinoma" in 1960, to describe papillary carcinomas ≤ 1.5 cm in diameter.

Several variants are recognized, although classical papillary thyroid carcinoma is the most frequent; microscopic, follicular variant, diffuse sclerosing variant, tall cell variant, columnar cell variant, hobnail variant, among others. The encapsulated follicular variant, specifically when noninvasive, has been newly reclassified as the noninvasive follicular thyroid neoplasm with papillary-like nuclear features.

Although papillary carcinoma has a propensity to invade lymphatics, it is less likely to invade blood vessels.

These kinds of tumors are most commonly unencapsulated, and they have a high tendency to metastasize locally to lymph nodes, which may produce cystic structures near the thyroid that are difficult to diagnose because of the paucity of malignant tissue. Furthermore, papillary tumors may metastasize to the lungs and produce a few nodules or the lung fields may exhibit a snowflake appearance throughout.

Other characteristics of the papillary carcinoma is that E.M. shows increased mitochondria, increased RER, as well as increased apical microvilli. Moreover, papillary carcinomas have an indolent growth, and 40 percent of cases spread out of the capsule.

Craniopharyngioma is a rare, usually suprasellar neoplasm, which may be cystic, that develops from nests of epithelium derived from Rathke's pouch. Rathke's pouch is an embryonic precursor of the anterior pituitary.

Craniopharyngiomas are typically very slow growing tumors. They arise from the cells along the pituitary stalk, specifically from nests of odontogenic (tooth-forming) epithelium within the suprasellar/diencephalic region and, therefore, contain deposits of calcium that are evident on an x-ray.

Papillary thyroid carcinoma is usually discovered on routine examination as an asymptomatic thyroid nodule that appears as a neck mass. In some instances, the mass may have produced local symptoms. This mass is normally referred to a fine needle aspiration biopsy (FNA) for investigation. FNA accuracy is very high and it is a process widely used in these cases. Other investigation methods include ultrasound imaging and nuclear scan. The ultrasound is a useful test to distinguish solid from cystic lesions and to identify calcifications. The thyroid ultrasound is also very effective to discover microcarcinomas, which refer to very small carcinomas (<1 cm).

Papillary thyroid carcinomas are also discovered when a hard nodule is found in multinodular goiter, when enlarged cervical lymph nodes are detected, or when there are unidentified metastatic lesions elsewhere in the body. Expanding lesions found in the thyroid gland, especially if they are painful, should be examined as they may indicate the presence of papillary thyroid carcinoma. Other clinical signs that could indicate papillary thyroid are fixation to the trachea, a firm neck mass, damage to recurrent laryngeal or cervical sympathetic nerves. Five percent of the population can have thyroid nodules, and the majority will be benign.

Appropriate workup includes an ultrasound of the neck, followed by lab studies. Patients will usually meet with both an endocrinologist and a surgeon (head and neck surgeon or endocrine surgeon).