RESUMO
BACKGROUND: Hypopigmented mycosis fungoides (HMF) is a rare subtype of mycosis fungoides (MF). We compared patients with exclusive hypopigmented lesions with a group of MF patients with concomitant different lesions. METHODS: 20 patients with HMF only and 14 patients with hypopigmented lesions concomitant with other types of lesions (mixed MF, MMF) were selected. Clinical-epidemiological analysis as well as histological and immunohistochemical studies were performed. RESULTS: HMF and MMF preserve some similarities, like predilection for dark-skinned persons and slow progression, but they also present differences: the exclusive variant is associated with early onset and a clear CD8+ immunophenotype, whereas MMF patients tend to present a predominance of CD4+ cell infiltrates. Histological analysis revealed similar findings; relapsing courses were common. CONCLUSION: Whether patients are suffering from exclusive HMF or MMF, the presence of hypopigmented lesions can be considered a marker of good prognosis in MF, since both groups presented similar data, such as staging and disease duration.
Assuntos
Hipopigmentação/patologia , Micose Fungoide/patologia , Neoplasias Cutâneas/patologia , Adolescente , Adulto , Idoso , Biópsia por Agulha , Criança , Estudos de Coortes , Diagnóstico Diferencial , Feminino , Seguimentos , Humanos , Hipopigmentação/diagnóstico , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Micose Fungoide/diagnóstico , Estudos Retrospectivos , Índice de Gravidade de Doença , Neoplasias Cutâneas/diagnóstico , Estatísticas não Paramétricas , Adulto JovemRESUMO
BACKGROUND: Hypopigmentation in hypopigmented mycosis fungoides (MF) is thought to result from the action of CD8+ cells on melanocytes. Here, we investigated the immunophenotype and melanocytic markers in hypopigmented MF lesions. METHODS: Specimens of hypopigmented lesions and normal skin from 18 patients with hypopigmented MF and specimens of non-hypopigmented lesions from 8 patients with classic/conventional MF were subjected to neoplastic immunophenotyping and melanocyte immunostaining with Melan-A, tyrosinase, stem cell factor receptor (CD117) and microphthalmia-associated transcription factor (MiTF). RESULTS: The CD8+ immunophenotype was more common in hypopigmented MF lesions (14/18) than in conventional MF lesions (1/8, p = 0.0033). There was a main effect of specimen type (hypopigmented MF lesion, hypopigmented MF normal skin, conventional MF lesion) on the number of melanocytes stained with Melan-A (median number/mm basal membrane, 1.97 vs. 4.77 vs. 5.42, respectively, p = 0.0046), tyrosinase (2.19 vs. 4.02 vs. 5.26, p = 0.0114), CD117 (4.29 vs. 7.81 vs. 5.45, p = 0.0064), and MiTF (2.75 vs. 4.43 vs. 4.98, p = 0.005). CONCLUSIONS: These results confirm previous findings of fewer melanocytes and CD117-positive melanocytes in hypopigmented MF and showed reduced MiTF identification, which is crucial for the function and survival of melanocytes. Thus cytotoxic CD8+ cell action may determine CD117/MiTF dysfunction, causing hypopigmentation.