Sean Klepper M.D.
Stephen Lyle, M.D., ...
- Indolent cutaneous T-cell lymphoma with a peak incidence in the fifth to seventh decades
- Gradual progression over a number of years through three clinical stages: patch, plaque and tumor
- If there is leukemic involvement, the term Sézary syndrome is used.
- Patch stage:
- Usually scant perivascular, band-like or periadnexal infiltrate of small lymphocytes, often with atypia (described as "cerebriform")
- Epidermotropism (tumor cells found within the epidermis): single cells and sometimes small collections
- Haloes around the intraepidermal lymphocytes may be present.
- Sometimes fibroplasia of the papillary dermis ("wiry collagen")
- Superficial dermal edema and vascular proliferation may be present.
- Absent to minimal spongiosis (helpful in the differential diagnosis with eczematous disorders, which may be indistinguishable from MF at this stage)
- Plaque stage:
- Dense band-like subepidermal infiltrate of neoplastic lymphocytes
- More significant epidermotropism with occasional Pautrier microabscesses (punched-out spaces within the epidermis filled with neoplastic lymphocytes)
- Tumor stage:
- Dense, nodular proliferation of tumor cells filling the upper dermis and extending deeper than in earlier stages
- There is often a significant decrease or loss of epidermotropism.
- The lymphocytes acquire a more significant degree of atypia, with nuclear enlargement, greater irregularity of the nuclear contour and hyperchromia.
- Immunophenotype: CD4+ (helper) T-cells (positive for CD2, CD3, CD5, CD7, CD45RO).
- Loss of one or more pan-T-cell marker may occur and is supportive evidence for a neoplastic process.