A review of the solitary cutaneous T-cell lymphomas.

Cutaneous T-cell lymphomas (CTCL) account for almost 65-92% of all cutaneous lymphomas, many of which usually present with multiple lesions. However, a number of well-recognized and rare types of CTCL, including mycosis fungoides, can present in isolated fashion. These solitary lesions often run a relatively indolent clinical course but often pose diagnostic difficulties. We review histopathologically challenging solitary cutaneous T-cell lymphomas, including criteria for diagnosis, clinical course and prognosis, particularly for primary cutaneous CD4+ small/medium pleomorphic lymphoma and indolent CD8+ lymphoid proliferation of acral sites. In addition, we suggest an algorithm and nomenclature to aid in the diagnosis of such problematic lesions.