| Objective:Pityriasis lichenoides chronica(PLC)is also known as parapsoriassis guttata.The current view is that pityriasis lichenoides chronica is a benign papular scaly disease of unknown etiology.There are three main hypotheses for its pathogenesis:an inflammatory reaction triggered by infectious agents,a cutaneous lymphoproliferative disorder,and an immune complexe mediated vasculitis.In a few cases,it has been reported that some cases of PLC evolving into mycosis fungoides(a kind of primary cutaneous T-cell lymphoma).Therefore,more and more scholars have agreed that PLC as a cutaneous T lymphocyte proliferative disease.Our study will review and analyze the clinical,histopathological,and immunohistochemical characteristics of PLC,and explore the rearrangement of TCR-y gene in its skin lesions,in order to further clarify the clinicopathological characteristics of PLC and its possible pathogenesis,to provide a reference for the diagnosis and treatment of PLC.Methods:The specimens were from 24 patients which were clinically and pathologically diagnosed as PLC,examined in the Department of Dermatology in the First Affiliated Hospital of Kunming Medical University between January 2013 and January 2019,an age range fromll to 66 is covered and the average age is(31.8±15.7).The clinical,histopathological and immunohistochemical data of 24 PLCs were retrospectively analyzed.DNA extraction kits were used to extract DNA from paraffin-embedded tissues of PLC patients,and the TCRy gene was amplified by PCR using the BIOMED-2 multiplex amplification system,amplified products were detected by capillary electrophoresis genescan for TCR? gene rearrangement.At the same time,TCRy positive mycosis fungoides patients were used as positive control,eczema patient were assigned to control group,and sterile deionized water was used as a blank control.The experimental results were analyzed by the software SPSS 22.0.The measurement data of normal distribution was tested by independent sample T,the non-normal distribution was tested by rank sum test,and the count data was tested by Fisher's exact probability method.The condition of P<0.05 was considered statistically significant.Results:1?Analysis results of clinical data:among the 24 PLC patients,there were 12 males and 12 females,with a male to female ratio of 1:1.The age of onset is 10-65,and the average age of onset is(31.0 ± 15.2).The incidence is the highest in the 10-19 age group.The shortest disease duration in 24 PLC patients was 1 month,the longest was 48 month,and the median was 5.5 month.Among the 24 PLC patients,10 cases involved trunk and limbs simultaneously,accounting for 41.7%,3 cases involving limbs,accounting for 12.5%,6 cases involving trunk,accounting for 25.0%,and 5 cases of generalized body,accounting for 20.8%.2?Histopathology:HE:among the 24 PLC patients,22 cases showed mild hyperkeratosis(91.7%),15 cases showed focal hypokeratosis(62.5%),14 showed spinal hypertrophy(58.3%),and 5 showed epidermal atrophy(20.8%),9cases(37.5%)showed keratinocyte necrosis,16 cases(66.7%)showed infiltration of the epidermis by lymphocytes,2 cases(8.3%)of red blood cells migration into the epidermis,3 cases(12.5%)of pauitrier-like microabscesses,and 7 cases of sponge edema(29.2%),23 cases(95.8%)of basal cell liquefaction degeneration,14 cases(58.3%)of dermal papilledema,21 cases(87.5%)of focal infiltration around intradermal blood vessels and appendages,3 cases(12.5%)of mossy infiltration,2 cases(8.3%)of dermal vascular injury,17 cases(70.8%)of red cell extravasation,and none of the cases have lymphoid atypia.Immunohistochemical:in 24 PLC patients,all cases expressed T cell markers(CD3,CD4,CD8),but the positive scores were different.Only 3 cases showed sparse CD20+.None of the 24 cases had CD30+cell infiltration.The CD8/CD4 ratios were examined among the 24 cases,there was a dominance of CD4 lymphocytes in 22 cases,CD8 lymphocytes predominated in the other 2 cases.3?Among the 24 patients with PLC,paraffin tissues in 11 cases(45.8%)had positive TCRy gene rearrangement,13 patients(54.2%)had negative result,and none of the 6 patients with eczema had gene rearrangement.Compared with the control group,P?0.045(<0.05),the difference was statistically significant.TCR? gene rearrangement has nothing to do with gender,age and disease duration.Conclusion:The disease duration of PLC ranges from several months to several years.The lesions mainly involve the limbs and trunk,The relatively characteristic histopathological manifestations of PLC are:hyperkeratosis,focal hypokeratosis,thickened spinous layer,and red blood cell overflow,and the infiltrating cells in the dermis and epidermis are mainly CD4?T lymphocytes.Some PLC patients have TCR? gene rearrangement in skin lesions.Such patients have the possibility of development into T-cell lymphoma and shouould be closely followed for a long time. |
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