• Clonal for T-cell receptor gene gamma rearrangement
Top Differential Diagnoses
• Mycosis fungoides
Is rarely CD8(+), but progression to tumor stage often takes years
• Lymphomatoid papulosis
More benign clinical course with papules that spontaneously regress
Clinical Photograph of AECTCL This is a clinical photograph of a large tumor on the posterior leg of a patient with aggressive epidermotropic cytotoxic T-cell lymphoma (AECTCL). As is typical of this disease, the lesion is extensively ulcerated. (Courtesy R. Willemze, MD.)
Low Magnification of AECTCL At scanning magnification of an AECTCL, there is a dense dermal lymphoid infiltrate, which also involves the epidermis. The dermal infiltrate is angiocentric, which is a common infiltration pattern in AECTCL.
AECTCL With Epidermotropism This is a medium magnification of a case of AECTCL with considerable epidermotropism . The T cells in the epidermis are medium in size with moderate atypia and coarse chromatin.
Break-Apart *ALK* FISH Probe This is a break-apart probe for the ALK gene by fluorescent in situ hybridization. The result is negative. No ALK gene rearrangement is seen in aggressive epidermotropic CD8(+) cytotoxic T-cell lymphoma.
. The T cells in the epidermis are medium in size with moderate atypia and coarse chromatin.
