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Pathophysiology · Chapter 17. NEOPLASMS

Functional atypia of tumors

The functional atypia of tumors is expressed in their hyperfunction or dysfunction, which ultimately leads to disruptions in the work of affected organs and disorders of the vital activity of the entire organism, forming tumor disease.

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Essence of atypiaManifests as cell hyperfunction or dysfunction.
HyperfunctionProduction of substances inadequate to the body's needs.
DysfunctionSynthesis of proteins uncharacteristic of normal autologous tissues.
MetastasisTransfer of cells and development of a tumor in another organ.
2 min readFor medical studentsUpdated 09/24/2026
Material prepared by WhiteCoat Pro editorial team based on platform study guidesReviewed by medical editor: Aulov A. A., general practitioner · 09/24/2026

Main manifestations of functional atypia

Changes in the functional activity of tumor cells are divided into two main forms. In general, such atypia leads to severe impairment of organ activity and disruption of the vital activity of the entire organism, which is regarded as tumor disease.

The following manifestations are distinguished:

  • Hyperfunction
  • Dysfunction
  • Hypofunction
  • Metaplasia
  • Degeneration

Tumor hyperfunction

This form is characterized by the production of substances that is inadequate to the current needs of the organism. The process can be carried out both by individual cells and by the neoplasm as a whole.

Most often, this phenomenon is observed in hormonally active neoplasms affecting endocrine glands.

Examples of tumors:

  • Pheochromocytomas (tumors of the adrenal medulla).
  • Corticosteromas and aldosteromas (tumors of the adrenal cortex).
  • Insulinoma (tumor of pancreatic beta cells).
  • Cancer of the thyroid, parathyroid, and other endocrine glands.
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Dysfunction and its mechanisms

Dysfunction consists in the appearance of signs in cells that are completely uncharacteristic of normal autologous tissues, i.e., those tissues from which the tumor originally developed.

Mechanism of development: In tumor cells, there is an expression of genes that program the synthesis of specific proteins characteristic of completely different cell types.

Examples of manifestations:

  • Low-differentiated gastric carcinoma cells are capable of producing collagen.
  • Lung cancer cells can produce biogenic amines or adenohypophyseal hormones.

Metastasis as a fatal property

Metastasis is a typical form of tumor growth atypia and one of the most dangerous properties of the malignant process. The essence of the process lies in the transfer of neoplasm cells to a certain distance from the main parent node and the subsequent development of a tumor of the same histological structure in a new tissue or another organ.

Briefly: answers to topical questions

What clinical symptoms does pheochromocytoma hyperfunction cause?

Clinical symptoms of pheochromocytoma hyperfunction are due to an excess of catecholamines. The following groups of manifestations are distinguished:

  • Cardiovascular disorders — arterial hypertension (constant or paroxysmal), hypertensive crises, acute hypotensive reactions with syncope, cardiac arrhythmias, as well as the development of pulmonary hypertension due to arteriole spasm.
  • Metabolic disorders — hyperglycemia, hyperlipidemia, and weight loss (catabolic effect).
  • Autonomic and other symptoms — sweating (hyperhidrosis), tremor, and retinopathy against the background of arterial hypertension.

Class and exam questions

What is the main difference between tumor hyperfunction and norm?

Hyperfunction is characterized by the production of substances that is inadequate to the actual needs of the organism.

What happens at the gene level during tumor cell dysfunction?

There is an expression of genes that program the synthesis of proteins specific to completely different cell types rather than the original tissues.

What are the main pathways of metastasis distinguished in pathophysiology?

Three main pathways are distinguished: lymphogenous (most frequent, characteristic of carcinomas), hematogenous (more common for sarcomas), and implantational.

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What else to study on this topic

  • Detailed analysis of the implantational pathway of metastasis
  • Features of lymphogenous metastasis in carcinomas
  • Mechanisms of hematogenous metastasis in sarcomas
  • Clinical manifestations of tumor disease
  • The role of hypofunction, metaplasia, and degeneration in the tumor process

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Other topics in "Chapter 17. NEOPLASMS"

Benign and malignant tumorsChemical carcinogensPhysical carcinogensOncogenes and tumor suppressor genesRisk factors for tumor growthTumor stages and tumor markersStages of carcinogenesisTumor AtypiaInvasive tumor growthAtypia of protein, lipid, and ion metabolism in tumorsMetabolic atypia of tumorsTumor MetastasisImpact of the tumor on the bodyAntitumor defense mechanismsAntitumor immunityPrevention and treatment of tumorsPlatelets in oncological diseases
Entire section "Chapter 17. NEOPLASMS"

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