Abstract

Lymphomatoid papulosis (LyP) is a cutaneous papulonodular skin disease that combines a benign clinical course with histological features of cutaneous T cell lymphoma. LyP is recognized to represent a heterogeneous collection of pathologically dissimilar subtypes. LyP with 6p25.3 rearrangement subtype represents (<5%) of LyP cases and is defined by chromosomal rearrangement of DUSP22 (6p25.3 locus). Reported cases are in elderly patients with distinctive pagetoid reticulosis like epidermotropism and biphasic CD30 expression pattern. We hereby present a novel case of LyP with 6p25.3 translocation and gamma/delta T cell immunophenotype in a young patient with unique clinical course. A 40-year-old female presents with skin-colored nodules, increasing in size on the left arm, no patches or plaques, and no history of cutaneous T cell lymphoma. The histology is remarkable for homogenous CD30 positive, dermal based, atypical large T lymphocytic infiltrate with no epidermotropism. The malignant T cells show mostly retained CD2 and CD3, positive gamma TCR, double negative CD4 and CD8, and loss of CD5. BetaF1, TIA-1, Granzyme B are negative. DUSP22 (IRF4) rearrangement was identified by FISH. Recurrence of the lesions in the thigh skin after two months was identified, and later dissemination to one lymph node was recognized. LyP A-E subtypes are stratified with either CD4 positive or CD8 positive T cells, alpha/beta or gamma/delta immunophenotype. This case of LyP with 6p25.3 in a young patient with large cell morphology, lack of pagetoid reticulosis like epidermotropism, lack of biphasic CD30 pattern and yet benign clinical course elicits the question, whether the double negative CD4 and CD8 (gamma/delta immunophenotype) is responsible for these differences, or the gamma/delta immunophenotype would comprise the basis for development of another, more malignant LPD such as primary cutaneous gamma/delta T cell lymphoma. Additional data and follow up are needed.

Financial Disclosure:
No current or relevant financial relationships exist.