Mycosis fungoides: clinical course and cellular abnormalities.

Mycosis fungoides is a lymphoma that appears to begin in skin. Although variable in its clinical course, it tends to affect middle-aged people, is present for a median of 4 yr before diagnosis, and generally results in death of the patient 4 to 5 yr after diagnosis. Cutaneous tumors and palpably enlarged lymph nodes are associated with shortened survival, and each of these frequently is accompanied by extracutaneous dissemination of the disease. The malignant cells are T lymphocytes with highly infolded nuclei, and they frequently express a helper cell function. Their chromosome complement has been found to be abnormal in karyotyping studies, and measurement of the amount of DNA by cytophotometry may permit diagnosis of the disease before the histological characteristics are detectable by light microscopy.