Cutaneous nonmycotic T- and natural killer/T-cell lymphomas: diagnostic challenges and dilemmas.

Mycosis fungoides is the prototype of primary cutaneous T-cell lymphoma and is more common in the West than in the East, whereas nonmycotic primary cutaneous T-cell lymphoma is more frequent than mycosis fungoides among Asians. Nonmycotic primary cutaneous T-cell lymphomas comprise several categories of neoplasms and might pose diagnostic challenges because of the rarity of these lesions and overlapping features among certain entities. The authors recommend diagnostic approaches including histopathological evaluation, immunohistochemical markers, and ancillary studies. Diagnostic dilemma in certain entities and cases with atypical clinicopathological features are discussed.