How are cutaneous T-cell lymphomas (CTCL) classified?

Updated: Aug 15, 2018
  • Author: Lauren C Pinter-Brown, MD; Chief Editor: Emmanuel C Besa, MD  more...
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Answer

Cutaneous T-cell lymphomas have been defined in the past by an integration of histologic, biologic, immunologic, and cytogenetic characteristics in two classification systems [25, 26] : the European Organization for Research and Treatment of Cancer (EORTC) classification for primary cutaneous lymphomas [25] and the World Health Organization (WHO) classification of hematologic malignancies. (See Pathophysiology, Etiology, Presentation, and Workup.) [26]

A tumor, node, metastases (TNM) classification system for primary cutaneous lymphomas other than mycosis fungoides and its variant Sézary syndrome has also been proposed. [27]

The EORTC classification focused on primary cutaneous lymphomas, which may vary from their nodal counterparts in clinical behavior, prognosis, and appropriate therapeutic approaches. [25] The classification also recognized that, unlike the general group of lymphomas, a histologic diagnosis in a case of cutaneous lymphoma may not be the final diagnosis, but may instead be a differential diagnosis that requires clinicopathologic correlation. (See Prognosis, DDx, Treatment, and Medication.)

The WHO classification included cutaneous lymphomas in the general classification of lymphoma to facilitate the description of clinicopathologic entities in their entirety, reporting common features of disease entities that may present in multiple anatomic sites. [26] The WHO classification allowed oncologists, dermatologists, and pathologists to use a common language.

In 2005, during consensus meetings, representatives of both systems reached an agreement on a new classification system, the WHO-EORTC Classification of Cutaneous Lymphomas. (See Table 1, below.) [1]

Table 1. WHO-EORTC Classification of Cutaneous T-Cell Lymphoma (Open Table in a new window)

WHO-EORTC Classification

Frequency (%)

5-Year Survival Rate (%)

Indolent Clinical Behavior

Mycosis fungoides

44

88

Mycosis fungoides variants and subtypes

—Folliculotropic mycosis fungoides

4

80

—Pagetoid reticulosis

< 1

100

—Granulomatous slack skin

< 1

100

Primary cutaneous CD30+ lymphoproliferative disorder

—Primary cutaneous anaplastic large cell lymphoma

8

95

—Lymphomatoid papulosis

12

100

Subcutaneous panniculitis-like T-cell lymphoma (provisional)

1

82

Primary cutaneous CD4+ small/medium-sized pleomorphic T-cell lymphoma (provisional)

2

75

Aggressive Clinical Behavior

Sézary syndrome

3%

24%

Adult T-cell leukemia/lymphoma

NR

NR

Extranodal NK/T-cell lymphoma, nasal type

NR

NR

Primary cutaneous peripheral T-cell lymphoma, unspecified

2

16

Primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma (provisional)

< 1

18

Cutaneous gamma/delta-positive T-cell lymphoma (provisional)

< 1

NR

Precursor Hematologic Neoplasm (not a T-cell lymphoma)

CD4+/CD56+ hematodermic neoplasm (blastic NK-cell lymphoma)

 

NR

 

NR

Source: Adapted from Willemze et al. Blood. 2005;105(10):3768-85. [1]

EORTC = European Organization of Research and Treatment of Cancer; NR = not reported; NK = natural killer; WHO = World Health Organization.

Table 2, below, summarizes various types of cluster designations and their representative cells.

Table 2. Cluster Designations (Open Table in a new window)

CD Type

Representative Cells

Also Known As

CD2

T, NK

Sheep RBC

CD3

T

 

CD4

T subset

Helper

CD5

T

 

CD7

T, NK

Prothymocyte

CD8

T subset, NK

Suppressor

CD25

Active T, B, M

IL-2R (Tac)

CD30

Active T, B

Ki-1

CD45

T subset

CLA

CD56

NK

NCAM

B = B cell; CD = cluster designation; CLA = common leukocyte antigen; IL-2R = interleukin-2 receptor; M = M cell; NCAM = neural cell adhesion molecule; NK = natural killer; RBC = red blood cell; T = T cell; Tac = Tac antigen.


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