Search Database ICD-O-3 Code Lists

Name

Primary cutaneous gamma-delta T-cell lymphoma (PCGD-TCL)

ICD-O-3 Morphology

9726/3: Primary cutaneous gamma delta T-cell lymphoma
Effective 2001 and later

Reportable

for cases diagnosed 1978 and later

Primary Site(s)

C440-C449 , C490-C499 , C510-C519 , C600-C609 , C632
Cutaneous (skin) lymphoma which presents with generalized skin lesions, mostly affecting the extremities (arms and legs).

Assign C449 if specific primary site cannot be determined.

See abstractor notes

Coding Manual: Hematopoietic Coding Manual (PDF)

Abstractor Notes

PCGD-TCL manifests as single or generalized skin and subcutaneous lesions, occasionally with mucosal involvement, without preferential sites of involvement

Diagnostic Confirmation

This histology can be determined by positive histology (including peripheral blood) with or without genetics and/or immunophenotyping. Review the Definitive Diagnostic Methods, Immunophenotyping and Genetics Data sections below, and the instructions in the Hematopoietic Manual for further guidance on assigning Diagnostic confirmation.

Module Rule

None

Alternate Names

None

Definition

Primary cutaneous gamma-delta T-cell lymphoma (PCGD-TCL) is a clonal proliferation of mature, activated γδ T cells of the Vδ1 or Vδ2 subset, arising within the skin and subcutaneous tissues. (WHO 5th edition)

Definitive Diagnostic Methods

Cytogenetics
Genetic testing
Histologic confirmation
Immunohistochemistry
Immunophenotyping

Genetics Data

Recurrent mutations of putative driver genes within JAK/STAT, MAPK, MYC
Mutations in chromatin modification pathways
Mutations in consensus cancer genes and tumor suppressor genes

Immunophenotyping

CD2+ (expression/positive)
CD3+ (expression/positive)
CD5- (no expression/negative)
TCRγ+ (expression/positive)
TCRδ+ (expression/positive)
TCRβ− (no expression/positive)

Treatments

Chemotherapy
Radiation therapy

Transformations to

There are no known transformations

Transformations from

There are no known transformations

Same Primaries

Corresponding ICD-10 Codes (Cause of Death codes only)

C84.4 Peripheral T-cell lymphoma

Corresponding ICD-10-CM Codes (U.S. only)

C84.A_ Cutaneous T-cell lymphoma, unspecified (effective October 01, 2015)
C84.AA Cutaneous T-cell lymphoma, unspecified, in remission (effective October 01, 2024)

Signs and Symptoms

Deep dermal subcutaneous tumors with or without necrosis and ulceration
Drenching night sweats
Fatigue
Fever (for no known reason)
Pain in the chest, abdomen or bones (for no known reason)
Skin patches/plaques
Weight loss (for no known reason)

Diagnostic Exams

Blood chemistry studies
Bone marrow aspiration and biopsy
CT (CAT) scan
Flow cytometry
Immunohistochemistry
Immunophenotyping
PET (positron emission tomography) scan
Skin biopsy

Progression and Transformation

None

Epidemiology and Mortality

Incidence: 0.05 per million per years
Age: median age 63
Sex: male predilection
Survival: median survival of < 2 years

Sources

WHO Classification of Tumours Editorial Board. Haematolymphoid tumours. Lyon (France): International Agency for Research on Cancer; 2024. (WHO classification of tumours series, 5th ed.; vol. 11). https://publications.iarc.who.int/637.
Section: Mature T-cell and NK-cell neoplasms
Pages: Part B: 702-704

International Classification of Diseases for Oncology, 3rd edition (including revisions). Geneva: World Health Organization, 2011, 2020.
Section: ICD-O-3.2 (2020) Morphological Codes
Pages: http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577

PDQ® Adult Treatment Editorial Board. PDQ Mycosis Fungoides and Other Cutaneous T-Cell Lymphomas Treatment. Bethesda, MD: National Cancer Institute. Updated <02/19/2025>. Available at: https://www.cancer.gov/types/lymphoma/hp/mycosis-fungoides-treatment-pdq. Accessed <03/31/2025>. [PMID: 2638928
Section: Mycosis Fungoides and Other Cutaneous T-Cell Lymphomas Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/lymphoma/hp/mycosis-fungoides-treatment-pdq
Glossary