Orthopedics - Oleksa A.P. 2006

Tumor-like lesions and bone tumors
Classification of tumors by their clinical course

Based on the biological properties and characteristics of natural development, all tumors (benign and malignant) can be divided into five categories, each exhibiting specific clinical and radiological features and requiring appropriate surgical interventions.

1. Benign latent course. The natural METABOLISM/13.html">History of the tumor process is characterized by slow development alongside normal patient growth, followed by a cessation of tumor growth and a tendency toward spontaneous regression. Such tumors never undergo malignant transformation and rapidly disappear following conventional curettage (ecochleation).

Class="center">Table 15. Histological Classification of Tumors of The Musculoskeletal System

Tissue of origin

Benign

Malignant

bone

osteoma

osteoid osteoma

osteoblastoma

osteosarcoma

Cartilage

enchondroma

osteochondroma

chondroblastoma

chondromyxoid

fibroma

chondrosarcoma

fibrous and fibrohistiocytic

non-ossifying fibroma (fibrous cortical defect)

benign fibrous histiocytoma

Fibrous Dysplasia

desmoplastic fibroma

Fibrosarcoma

malignant fibrous

histiocytoma

hematopoietic

eosinophilic

granuloma

Ewing's Sarcoma

lymphoma

myeloma

vascular

hemangioma

cystic angiomatosis

lymphangioma

glomus tumor

hemangioendothelioma

angiosarcoma

hemangiopericytoma

Other Tumors and Tumor-like Conditions

Benign

Malignant

solitary bone cyst

aneurysmal bone cyst

intraosseous Lipoma

fibrochondroplastic mesenchymoma

adamantinoma of long bones

chordoma

leiomyosarcoma of bone

metastatic tumors

Tumors and Tumor-like Lesions of Joints

Benign

Malignant

synovial chondromatosis

pigmented villonodular synovitis

synovial hemangioma

synovial sarcoma

synovial chondrosarcoma

2. Benign course with active growth.

The clinical course is characterized by active tumor growth. In some cases, a reactive zone persists following tumor ecochleation.

3. Benign aggressive course.

This course is distinguished by aggressive local growth, though the tumor does not metastasize. Histological examination reveals tumor penetration through the capsule into the reactive zone. Local control is achieved only by wide resection of the tumor within healthy tissue beyond the reactive zone.

4. Malignant course (low grade).

These tumors metastasize late. True histological encapsulation is absent, with findings being more characteristic of a pseudocapsule. Tumor masses reside within the reactive zone and rarely extend beyond it. Local control can be achieved only by complete removal of the tumor (including

the reactive zone) within healthy Tissues.

Such tumors are curable solely through surgical intervention, and systemic therapy is not required.

5. Malignant course (high grade).

This course is characterized by rapid tumor growth and early metastasis. Tumor masses are found both within the reactive zone and at some distance beyond it, i.e., within normal tissues. Achieving local control over the tumor process requires both Surgical Treatment and systemic therapy to prevent metastasis.

In 1983, William Enneking and other members of the Musculoskeletal Tumor Society (MSTS) proposed a surgical staging system for malignant and benign processes, as presented in Tables 16 and 17.

Currently, Ukraine employs a clinical staging system based on four elements: 1) tumor extent (T); 2) regional Lymph node status (N); 3) presence of distant metastases (M); 4) histological grade of the tumor (G) — Table 18.

Table 16. Staging of Malignant Processes

Stage

Histological Grade

Tumor Localization (Extent)

Presence of Metastases

I A

low (G1)

intracompartmental (T1)

I B

extracompartmental (T2)

none (M0)

II A

high (G2)

intracompartmental (T1)

II B

extracompartmental (T2)

none (M0)

III A III B

low (G1) high (G2)

T1 or T2

regional or distant (M1)

Table 17. Staging of Benign Tumors

Stage

Histological Grade

Extent of Process

Presence of Metastases

Clinical Course

I

G0 (histologically benign tumor, no malignant Cells)

T0

M0

latent

II

G0

T0

M0

active progressive

III

G0

T1-2

M0-1

aggressive, invasive, destruction of surrounding structures

Table 18. Stage Grouping

Stage

Histological differentiation

Primary tumor

Regional Lymph Nodes

Distant metastases

I A

G1,2

Т1

N0

M0

I B

G1,2

Т2

N0

M0

II А

G3,4

Т1

N0

M0

II В

G3,4

Т1

N0

M0

III

not determined

IV А

any G

any T

N1

M0

IV В

any G

any T

any N

M1

TNM clinical classification

Primary tumor

Тх — primary tumor cannot be assessed

Т0 — no evidence of primary tumor

Т1 — tumor limited to the cortical bone

Т2 — tumor extends beyond the cortical bone

Regional lymph nodes

Nx — regional lymph nodes cannot be assessed

N0 — no regional lymph node metastasis

N1 — regional lymph node metastases present

Distant metastases

Мх — distant metastases cannot be assessed

М0 — no distant metastases

М1 — distant metastases present

Histological differentiation

Gx — differentiation grade cannot be assessed

G1 — well-differentiated

G2 — moderately differentiated

G3 — poorly differentiated

G4 — undifferentiated

Note: Ewing's sarcoma and primary bone lymphoma are graded as G4.



Last update: 10/08/2026

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