ALK and primary cutaneous T-cell non-Hodgkin lymphoma: The prognosis of PTCL is poor with the exception of the ALK (anaplastic lymphoma kinase) expressing anaplastic large cell lymphoma (ALCL) with a more favourable outcome after conventional chemotherapy and the primary cutaneous T-cell lymphomas (CTCL) that usually show an indolent clinical course [17, 18].