Cutaneous manifestations of peripheral T-cell lymphoma, not otherwise specified: a case series highlighting the diagnostic challenges for this heterogeneous group.

Peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS) is a rare, heterogeneous group of nodal and extranodal mature T-cell lymphomas that do not correspond to any of the defined T-cell entities, according to the World Health Organization classification. Most cases present with late stage nodal disease; however extranodal involvement is common. Skin and subcutaneous involvement is reported in approximately 20% of cases. Little attention has been given to the highly variable skin manifestations in the literature. It is our experience that lesions can present in ways other than previously described nodular or tumourous lesions that often ulcerate. We present a case series from a large tertiary institution of seven cases of PTCL, NOS with skin involvement, highlighting the variable presentations and diagnostic challenges for this heterogeneous group.