A patient with clinicopathologic features of small plaque parapsoriasis presenting later with plaque-stage mycosis fungoides: Report of a case and comparative retrospective study of 27 cases of "nonprogressive" small plaque parapsoriasis

作者：Belousova Irena E; Vanecek Tomas; Samtsov Alexey V; Michal Michal; Kazakov Dmitry V^*

来源：Journal of the American Academy of Dermatology, 2008, 59(3): 474-482.

DOI：10.1016/j.jaad.2008.05.028

Background: It is unsettled whether small plaque parapsoriasis (SPP) represents an inflammatory dermatosis or has a potential to transform into mycosis fungoides (MF) or is, in fact, MF. The literature contains no fully documented example of progression of SPP into MF.
Objective: The purpose of our study was to present a patient with clinical features of SPP who later develop plaque-stage MF, as seen both clinically and pathologically and to compare the clinicopathologic feature of this unique case with 27 "nonprogressive" SPP cases.
Methods: This study is a prospective and retropective evaluation of 28 patients, using light microscopy, immunohistochemistry, and molecular biology.
Results: A 56-year-old man with a 3-year history of persistent SPP with typical small (<5 cm), elongated and "digitate" lesions presented with newly developed larger patches and plaques. Whereas histologic examination of the patch lesion revealed relatively nonspecific features, a specimen of the crusted plaque showed a dense lymphoid infiltrate composed of small cerebriform the basal layer of the epidermis and formed small collections. There were atypical mitotic figures. Immunohistochemically, an aberrant immunopheno-type with the loss of CD5 expression was found in the plaque specimen. T-cell receptor (TCR)- gamma gene rearrangement studies detected clones in the plaque and in the peripheral blood (biallelic in blood), while the patch tested polyclonal. The 27 SPP patients included 23 men a 4 women, ranging in age from 29 to 75 years. They were followed up and treated for 1.2 to 52 years (mean 10); no patient's SPP progressed into MF. All patients presented with small patch lesions measuring 3 to 6 cm lengthwise and 0.5 to 2 cm in width. Histologic features were nonspecific. Molecular genetic studies revealed the following results: two cases tested polyclonal, 3 cases demonstrated the oligoclonal pattern, whereas the remaining 13 specimens showed a pattern which can be interpreted as oligoclonal or pseudomonoclonal.
Limitations: Oligoclonal and monoclonal patterns were overrepresented in the SPP group, which may be due to the low amont and, probably, suboptimal quality of DNA used in the TCR-gamma rearrangement studies.
Conclusions: Occasionally patients with the clincal and pathologic presentation of SPP may develop typical features for MF. This event seems to be extremely rare; at present there appears to be no means to predict such a course. The vast majority of SPP patients will never have disease progression to MF.

• 出版日期2008-9
• 单位中国人民解放军军事医学科学院