Lymphoma of the Skin

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Early Detection, Diagnosis, and Staging TOPICS

How is lymphoma of the skin staged?

Once skin lymphoma is diagnosed, tests are done to determine the stage (extent of spread) of the disease. The tests used to gather information for staging include:

  • Physical exam
  • Biopsies
  • Imaging tests, such as CT scans
  • Blood tests

These tests are described in the section “How is lymphoma of the skin diagnosed?

Knowing the stage of the lymphoma may help in deciding the best treatment and in predicting a patient’s prognosis (outlook), but staging is not as important for skin lymphomas as it is for many other types of cancer.

A staging system is a standard way to describe the extent of cancer spread. The staging systems for skin lymphomas were developed by the International Society for Cutaneous Lymphomas (ISCL) and the European Organization for Research and Treatment of Cancer (EORTC). There are 2 different staging systems – one for mycosis fungoides and Sezary syndrome and another for the other skin lymphomas. These systems are complex and can be hard to understand. If you have questions about the stage of your lymphoma, ask your cancer care team to explain it to you in a way you understand. This can help you make informed choices about your treatment.

Staging for mycosis fungoides and Sezary syndrome

Mycosis fungoides (MF) and Sezary syndrome are staged based on 4 factors:

  • T describes how much of the skin is affected by the lymphoma (tumor).
  • N describes the extent of the lymphoma in the lymph nodes.
  • M is for the spread (metastasis) of the lymphoma to other organs.
  • B is for lymphoma cells in the blood.

T categories

T1: Skin lesions can be small patches (flat lesions), papules (small bumps), and/or plaques (raised or lowered, flat lesions), but the lesions cover less than 10% of the skin surface.

T2: The patches, papules, and/or plaques cover 10% or more of the skin surface.

T3: At least one of the skin lesions is a tumor that is at least 1 centimeter (cm) across (a cm is a little less than 1/2 inch).

T4: The skin lesions have spread, grown larger, and grown together to cover at least 80% of the skin surface.

N categories

N0: Lymph nodes are not enlarged and a lymph node biopsy is not needed.

N1: Lymph nodes are enlarged, but the patterns of cells look normal or close to normal under the microscope.

N2: Lymph nodes are enlarged, and the patterns of cells look more abnormal under the microscope.

N3: Lymph nodes are enlarged, and the patterns of cells look very abnormal under the microscope.

NX: Lymph nodes are enlarged but haven't been removed to be looked at under the microscope.

M categories

M0: The lymphoma cells have not spread outside the skin or lymph nodes.

M1: Lymphoma cells have spread to other organs or tissues, such as the liver or spleen.

B categories

B0: Less than 5% of lymphocytes in the blood are Sezary cells.

B1: Low numbers of Sezary cells in the blood (more than in B0 but less than in B2).

B2: High number of Sezary cells in the blood (at least 1,000 cells per microliter).

Stage grouping

Once the values for T, N, M, and B are known, they are combined to determine the overall stage of the lymphoma. This process is called stage grouping.

Stage IA: T1, N0, M0, B0 or B1

There are skin lesions but no tumors. Skin lesions cover less than 10% of the skin surface (T1), the lymph nodes are not enlarged (N0), lymphoma cells have not spread to other organs or tissues (M0), and the number of Sezary cells in the blood is not high (B0 or B1).

Stage IB: T2, N0, M0, B0 or B1

There are skin lesions but no tumors. Skin lesions cover at least 10% of the skin surface (T2), the lymph nodes are not enlarged (N0), lymphoma cells have not spread to other organs or tissues (M0), and the number of Sezary cells in the blood is not high (B0 or B1).

Stage IIA: T1 or T2, N1 or N2, M0, B0 or B1

There are skin lesions but no tumors. Skin lesions can cover up to 80% of the skin surface (T1 or T2). The lymph nodes are enlarged but the patterns of cells do not look very abnormal under the microscope (N1 or N2). Lymphoma cells have not spread to other organs or tissues (M0), and the number of Sezary cells in the blood is not high (B0 or B1).

Stage IIB: T3, N0 to N2, M0, B0 or B1

At least one of the skin lesions is a tumor that is 1 cm across or larger (T3). The lymph nodes are either normal (N0) or are enlarged but the patterns of cells do not look very abnormal under the microscope (N1 or N2). Lymphoma cells have not spread to other organs or tissues (M0), and the number of Sezary cells in the blood is not high (B0 or B1).

Stage IIIA: T4, N0 to N2, M0, B0

Skin lesions cover at least 80% of the skin surface (T4). The lymph nodes are either normal (N0) or are enlarged but the patterns of cells do not look very abnormal under the microscope (N1 or N2). Lymphoma cells have not spread to other organs or tissues (M0), and there are few (or no) Sezary cells in the blood (B0).

Stage IIIB: T4, N0 to N2, M0, B1

Skin lesions cover at least 80% of the skin surface (T4). The lymph nodes are either normal (N0) or are enlarged but the patterns of cells do not look very abnormal under the microscope (N1 or N2). Lymphoma cells have not spread to other organs or tissues (M0), and the number of Sezary cells in the blood is low (B1).

Stage IVA1: any T, N0 to N2, M0, B2

Skin lesions can cover any amount of the skin surface (any T). The lymph nodes are either normal (N0) or are enlarged but the patterns of cells do not look very abnormal under the microscope (N1 or N2). Lymphoma cells have not spread to other organs or tissues (M0), and the number of Sezary cells in the blood is high (B2).

Stage IVA2: any T, N3, M0, any B

Skin lesions can cover any amount of the skin surface (any T). Some lymph nodes are enlarged and the patterns of cells look very abnormal under the microscope (N3). Lymphoma cells have not spread to other organs or tissues (M0). Sezary cells may or may not be in the blood (any B).

Stage IVB: any T, any N, M1, any B

Skin lesions can cover any amount of the skin surface (any T). The lymph nodes may be normal or abnormal (any N), and Sezary cells may or may not be in the blood (any B). Lymphoma cells have spread to other organs or tissues, such as the liver or spleen (M1).

Staging for other skin lymphomas

The staging system for types of skin lymphoma other than mycosis fungoides and Sezary syndrome is still fairly new, and doctors are still trying to determine how useful it is. The system includes 3 factors:

  • T describes how much of the skin is affected by the lymphoma (tumor).
  • N describes the extent of the lymphoma in the lymph nodes.
  • M is for the spread (metastasis) of the lymphoma to other organs.

For these lymphomas, only the T category is used at the time of diagnosis. If sites besides the skin are involved at the time of diagnosis (such as lymph nodes), these lymphomas are no longer considered skin lymphomas and they are staged like regular non-Hodgkin lymphoma. The N and M categories are only used if the lymphoma progresses (continues to grow) during treatment or comes back after treatment.

T categories

T1: There is only a single skin lesion.

    T1a: The skin lesion is less than 5 cm (about 2 inches) across.

    T1b: The skin lesion is larger than 5 cm across.

T2: There are 2 or more places on the skin with lymphoma. These places may be in a single body region or in 2 body regions that are next to each other.

    T2a: All of the skin lesions could be placed within a circle that is 15 cm (about 6 inches) across.

    T2b: The circle needed to surround all of the skin lesions is larger than 15 cm across, but smaller than 30 cm across.

    T2c: The circle needed to surround all of the skin lesions is larger than 30 cm across.

T3: There are skin lesions in body regions that aren’t next to each other, or in at least 3 different body regions.

    T3a: There are many lesions involving 2 body regions that aren’t next to each other.

    T3b: There are many lesions involving 3 or more body regions.

N categories

N0: None of the lymph nodes is enlarged or contain lymphoma cells.

N1: There are lymphoma cells in the lymph nodes that drain an area where skin contained lymphoma.

N2: One of the following is true:

  • At least 2 sets of lymph nodes from different areas contain lymphoma cells
  • There are lymphoma cells in lymph nodes that do not drain areas where the skin contained lymphoma.

N3: Lymph nodes deep inside the chest or abdomen contain lymphoma cells.

M categories

M0: No signs of lymphoma outside of the skin or lymph nodes.

M1: Lymphoma has spread to other organs or tissues.

This system does not assign an overall stage to the lymphoma, as the system for mycosis fungoides/Sezary syndrome does. Because this system is still fairly new, it’s not yet clear how well it can help predict a person’s prognosis (outlook).


Last Medical Review: 03/14/2013
Last Revised: 02/11/2014