Abstract
T/NK cells are involved in approximately 85% of primary cutaneous lymphomas, and more than half of the cases are mycosis fungoides (MF) and Sezary syndrome. Primary cutaneous lymphoma is classified functionally based on clinical behavior, histology and surface characteristics; the diagnostic rate has improved due to implementation of clonality analysis. We examined the progression to lymphoma in 14 cases that were clinicopathologically diagnosed as lichen planus (LP); 18 as parapsoriasis en plaques (PP), an inflammatory disorder; and 8 (28 samples) as MF in Showa University Hospital from 1993 to 2011. Immunohistochemical staining was performed on all samples, and PP and MF samples were further examined by clonality analysis. Dissociation of CD4/CD8 was not found in any LP samples, but was revealed in 33% of PP and 88% of MF samples. There was a strong tendency for a decrease of CD7 in PP and MF samples. CCR3 was negative in all LP, PP, and MF samples. CCR4 and CXCR3 were positive in many more PP and MF samples, compared with LP samples. All of the PP samples were negative in the T-cell clonality analysis, but 50% of MF samples were positive. These results suggest that the surface properties of PP are closer to those of MF, rather than LP. Therefore, PP may also have the potential for tumorous change, in addition to being an inflammatory skin disease. Moreover, the validity of the clonality analysis in auxiliary diagnosis of MF should be checked further.
