Cutaneous T-cell lymphomas (CTCL) are staged differently depending on the type of cutaneous lymphoma. Typical procedures done to stage cutaneous lymphoma include a complete physical exam (including a thorough skin exam); a skin biopsy (removal of a small piece of tissue) for examination under the microscope by a pathologist (a doctor who studies tissues and cells to identify diseases), and blood tests. Other tests that might be performed could include lymph node biopsy, bone marrow biopsy, and imaging tests such as CT (computerized axial tomography and/or PET (positron emission tomography) scans. 

The staging of the most common type of CTCL, mycosis fungoides/Sézary syndrome (MF/SS) is classified into stages IA through IVB using the T (tumor, which for CTCL is patches or plaques), N (lymph node), M (presence of metastasis), B (presence of blood involvement) (TNMB) system. The level of disease is evaluated based on the size of the plaques or patches of affected skin (T1–T4); the presence or number of cancer cells in lymph nodes (N0–N3); the presence of blood involvment (B0–B2), and the presence of metastasis (M0–M1).

For MF/SS, stages IA, IB, and IIA are considered early-stage disease. Stages IIB through IVB are considered advanced-stage disease, where the cancer is more widespread and/or has moved outside the skin to other places in the body such as the lymph nodes or other organs. 

The following are an explanation of the stages for cutaneous T-cell lymphoma:

Stage IA:

Less than 10% of the skin is covered in red patches or plaques, and there is no blood, lymph node, or internal organ involvement.

Stage IB:

10% or more of the skin is covered in patches or plaques, and there is no blood, lymph node, or internal organ involvement.

Stage IIA:

Any amount of the skin surface is covered with patches or plaques and lymph nodes are enlarged and inflamed, but the cancer has not spread to the lymph nodes.

Stage IIB:

One or more tumors are found on the skin, lymph nodes may be enlarged, but cancer has not spread to the lymph nodes.

Stage III:

Nearly all of the skin is reddened and may have patches, plaques or tumors; lymph nodes may be enlarged, but cancer has not spread to them.

Stage IVA:

Most of the skin is reddened and cancer is found in the blood; cancer may have spread to the lymph nodes but does not involve other internal organs.

Stage IVB:

Most of the skin is reddened, and cancer is found in the blood; cancer may have spread to the lymph nodes and has spread to other organs.