Role of histology in providing prognostic information in mycosis fungoides.

Many patients who present with patch and early plaque stage mycosis fungoides follow an indolent course and survive for many years following diagnosis. A certain subset of patients, however, have rapidly progressive disease leading to accelerated demise. We examined 21 histologic sections from initial biopsies taken from patients with stable disease and 26 from patients with rapidly progressive disease in order to evaluate the role of histology in predicting the disease course. Two or three authors examined each case and scored each of 24 histologic parameters using a previously described four-point scale with no knowledge of the patients' clinical courses. Interobserver agreement was quite high. The only histologic parameter that demonstrated statistical differences between the two groups of patients was degree of acanthosis. The degree of spongiosis, number of eosinophils, amount of hyperconvolution of dermal lymphocytes and density of the dermal infiltrate approached statistical significance but did not attain this level. All of these differences were quite small. No differences were seen for the other 19 parameters. Patients with rapidly progressive disease tended to have more acanthosis, a few more hyperconvoluted dermal lymphocytes, a slightly greater number of eosinophils and perhaps a slightly more dense dermal infiltrate than patients who had stable disease. However, as all of these changes were very slight, it appears unlikely that evaluation of any single biopsy specimen for the histologic parameters we studied is helpful in predicting the prognosis for a specific patient.