11
Learning The Basics
1
Cutaneous B-Cell Lymphoma (CBCL)
As discussed in Chapter 1, in general, B-cell non-Hodgkin’s lymphomas are
much more common than T-cell non-Hodgkin’s lymphomas (85% versus
15%). However, in the skin, the opposite is true: CTCL makes up about
75-80% of all cutaneous lymphomas, whereas CBCL makes up about
20-25%. CBCLs are B-cell non-Hodgkin’s lymphomas which originate in
skin-based B-cells. The fact that most skin-resident lymphocytes are T-cells,
rather than B-cells, may explain the difference.
Since systemic or nodal B-cell non-Hodgkin’s lymphomas can secondarily
involve the skin, when a skin biopsy shows B-cell lymphoma it is very
important to make sure that the skin is the only organ involved and that
there is not a systemic non-Hodgkin’s lymphoma. There is no way to tell
the difference between a CBCL and a systemic B-cell lymphoma just based
on the biopsy. The three primary types of CBCL are primary cutaneous
marginal zone B-cell lymphoma (PCMZL); primary cutaneous follicle
center lymphoma (PCFCL); and primary cutaneous diffuse large cell
lymphoma, leg type (PCLBCL-LT).
PCMZL and PCFCL are slow-growing lymphomas and are classified as
indolent. They respond well to mild treatments, though they often recur.
Relapses of slow-advancing CBCL are always confined to the skin and
rarely life-threatening. Given the slow, non-threatening nature of this type
of the disease, some cases may not even warrant treatment.
PCFCL is the most common type of CBCL. It most commonly shows on
the head, neck or upper torso. Lesions are pink or red nodules, or slowly-
developing tumors. They rarely become open sores or ulcers. Some patients
find nodules in many locations on the body, but more often it is a single
tumor or small group of nodules.
PCMZL is also a slow-growing B-cell lymphoma which is related to
a type of non-Hodgkin’s lymphoma known as extranodal lymphoma of
mucosa associated lymphoid tissue (MALT) type. This is the second most
common form of CBCL. Patients find pink or red papules, nodules or, less
frequently, tumors. It can occur anywhere on the skin but tends to show up
on arms, legs or torso.
Diffuse large cell lymphoma, leg type, also known as PCLBCL-LT, is a
rare and more dangerous type of CBCL that looks much different under
