What are the histologic findings of cutaneous gamma/delta-positive T-cell lymphoma?

Updated: Aug 15, 2018
  • Author: Lauren C Pinter-Brown, MD; Chief Editor: Emmanuel C Besa, MD  more...
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Answer

Cutaneous gamma/delta-positive T-cell lymphoma has 3 major histologic patterns of involvement that can be present in the skin; specifically, epidermotropic, dermal, and subcutaneous. [31] More than 1 is often present in the same patient in different biopsy specimens or within a single biopsy specimen. [57] The lymphoma cells are generally medium to large, with coarsely clumped chromatin; large blastic cells with vesicular nuclei and prominent nucleoli are infrequent and apoptosis and necrosis are common, often with angioinvasion. The subcutaneous involvement may demonstrate rimming of fat cells.

Cutaneous gamma/delta-positive T-cell lymphoma cells are generally of beta-F1-, CD3+, CD2+, CD5-, CD7+/-, CD56+ phenotype with strong expression of cytotoxic proteins. [31] Most lack both CD4 and CD8, although CD8 may be expressed in some cases. [57, 92] In frozen-section specimens, the lymphoma cells are strongly positive for TCR -delta. If only paraffin sections are available, the absence of beta-F1 may be used to infer a gamma/delta origin. [93]

The lymphoma cells show clonal rearrangement of the TCR -gamma gene, while TCR -beta may be rearranged or deleted but is not expressed. EBV test results are usually negative. [57]


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