Primary cutaneous gamma-delta T-cell lymphoma

ICD-O-3 Morphology

9726/3: Primary cutaneous gamma delta T-cell lymphoma
Effective 2010 and later


for cases diagnosed 2010 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). See Module 7.

Abstractor Notes

(This code is effective for cases diagnosed 2010 and later. For cases diagnosed prior to 2010, see codes 9702/3 or 9709/3.)

1. Epidermorphic with presentation of patches and/or plaques.
2. Deep dermal or subcutaneous tumors with or without epidermal necrosis and ulceration.
3. Dissemination to mucosal or extranodal sites. Involvement of lymph nodes, spleen, or bone marrow is uncommon.

Resistant to multiagent chemotherapy and/or radiation and has a poor prognosis. Patients with subcutaneous involvement tend to have a more unfavorable prognosis.

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.


Not Applicable

Module Rule


Alternate Names



Primary cutaneous gamma-delta T-cell lymphoma (PCGD-TCL) is a lymphoma involving primarily the skin, composed of a clonal proliferation of mature, activated gamma delta T cells with a cytotoxic phenotype.

Definitive Diagnostic Methods

Genetic testing
Histologic confirmation

Genetics Data

EBV negative
TR genes are clonally rearranged


Beta F1+ (expression/positive)
CD2- (no expression/negative)
CD3+ (expression/positive)
CD4- (no expression/negative)
CD5- (no expression/negative)
CD7+/- (positive and negative)
CD8- (no expression/negative)
CD56+ (expression/positive)
Granzyme B+ (expression/positive)
Perforin+ (expression/positive)
TCR+ (expression/positive)
TIA1+ (expression/positive)


Radiation therapy

Transformations to

There are no known transformations

Transformations from

There are no known transformations

Corresponding ICD-9 Codes

202.8 Other lymphoma

Corresponding ICD-10 Codes

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)

Signs and Symptoms

Deep dermal subcutaneous tumors with or without necrosis and ulceration
Drenching night sweats
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
CT (CAT) scan
Flow cytometry
PET (positron emission tomography) scan
Skin biopsy

Progression and Transformation


Epidemiology and Mortality

Age: mostly in adults
Incidence: <1% of cutaneous T-cell lymphomas
Sex: no male or female predominance
Survival: 15 months median survival


Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds):
WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition)
IARC: Lyon 2017
Section: Mature T- and NK-cell neoplasms
Pages: 397-399

International Classification of Diseases for Oncology, Third Edition, Second Revision. Geneva: World Health Organization, 2020.
Section: ICD-O-3.2 (2020) Morphological Codes

National Cancer Institute
Section: General Information About Adult Non-Hodgkin Lymphoma (NHL)