What is a neoplasm (tumor)?

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Last updated: May 13, 2025View editorial policy

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From the Guidelines

A neoplasm is an abnormal growth of cells that serves no physiological function and can be benign or malignant, as defined by the World Health Organization classification of tumors living evidence gap map by tumour type group 1.

Definition and Characteristics

A neoplasm develops when cells begin to multiply uncontrollably due to genetic mutations that disrupt normal cell growth regulation.

  • Benign neoplasms grow locally without invading surrounding tissues or spreading to distant sites.
  • Malignant neoplasms (cancers) can invade adjacent structures and metastasize to other parts of the body. The behavior of neoplasms depends on their tissue of origin, with some growing slowly and causing few symptoms, while others progress rapidly and can be life-threatening.

Diagnosis and Treatment

Treatment approaches vary based on the type, location, and stage of the neoplasm, potentially including surgical removal, radiation therapy, chemotherapy, immunotherapy, or targeted therapies.

  • Early detection through appropriate screening is crucial for improving outcomes, especially for malignant neoplasms, as treatment is generally more effective when initiated before extensive spread has occurred 1. The term “tumor” is used synonymously with neoplasm, as similarly defined in the human classification and the mouse models of human cancers consortium 1.

Importance of Accurate Diagnosis

Accurate diagnosis and staging of neoplasms are essential for determining the best course of treatment and predicting patient outcomes.

  • The World Health Organization classification of tumors provides a framework for the diagnosis and classification of neoplasms, and is regularly updated to reflect new evidence and advances in the field 1.

From the Research

Definition of Neoplasm

A neoplasm is a clonal proliferation, meaning it is a condition characterized by the abnormal growth of cells that are derived from a single cell type 2.

Characteristics of Neoplastic Conditions

Neoplastic conditions are consisted of a single cell type, whereas non-neoplastic conditions consist of multiple different cell types 2.

Types of Neoplasms

Neoplasms can be classified into two main categories:

  • Epithelial tumors: characterized by oval-round to polygonal tumor cells, formation of tumor cell nests, and well-formed desmoplastic stroma 2
  • Mesenchymal tumors: characterized by spindle-shaped tumor cells, diffuse arrangement in sheets, and lack of desmoplastic stroma 2

Benign vs Malignant Neoplasms

The main differences between benign and malignant tumors include:

  • Differentiation: benign tumors are well-differentiated, while malignant tumors are often poorly differentiated 2, 3
  • Growth rate: benign tumors grow slowly, while malignant tumors grow rapidly 2, 3
  • Growth pattern: benign tumors show expansile growth with encapsulation, while malignant tumors show invasive growth with no capsule 2, 3
  • Metastasis: benign tumors do not metastasize, while malignant tumors frequently metastasize 2, 3

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Diagnostic approach and prognostic factors of cancers.

Advances in anatomic pathology, 2011

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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