DUSP22 rearrangement in primary cutaneous T cell lymphoma with features intermediate between mycosis fungoides, anaplastic large-cell lymphoma and lymphomatoid papulosis

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma, primary cutaneous CD30+ lymphoproliferative disorders (pc CD30+ LPD) being the second most prevalent. There is evidence that MF and pc CD30+ LPD may coexist and share T-cell clonality, suggesting a common origin. These findings were supported by a T-cell receptor clonality assessment by the polymerase chain reaction coupled with capillary electrophoresis, although results produced by this method may be ambiguous. We describe an otherwise healthy 46-year-old man who developed, over the course of 5 months, a tumor consisting of primary cutaneous anaplastic large cell lymphoma and, subsequently, several papules of lymphomatoid papulosis (LyP). Both lymphomas appeared on a single patch of MF, which had been present on the patient's right buttock for at least 2 years. T-cell receptor clonality of the 3 types of neoplastic lesions and apparently non-involved skin were assessed by a next-generation sequencing-based method. We found that MF, primary cutaneous anaplastic large cell lymphoma and LyP harbored the same top 2 clones. Non-involved skin harbored other T-cell clones. In this patient, these findings suggest that MF, LyP and pc CD30+ LPD were different clinicopathological manifestations arising from the neoplastic proliferation of the same T-cell clone.