Mycosis fungoides patient accompanied actinic keratosis, actinic keratosis with squamous cell carcinoma transformation, and porokeratosis after NBUVB therapy – 1st case report and review of the literature

INTRODUCTION Mycosis fungoides (MF) is the most common form of primary cutaneous T cell lymphoma. Narrowband ultraviolet B light (NBUVB) is used increasingly in treating MF because of its good toleration and well-established management. CONCERNS To discuss the risk factors and underlying pathogenic factors in the patients with secondary skin diseases after NBUVB therapy. METHODS We report in details the first case of a patient with MF accompanied with actinic keratosis (AK), AK with squamous cell carcinoma (SCC) transformation and porokeratosis after NBUVB therapy. Meanwhile, Sequence variants in tumor suppressor p53 gene in the patient's specimens were detected. A literature search of the key word "narrowband ultraviolet B light "and "side effects" was performed on PubMed, 14 cases of this entity were found. A total of 15 patients including our case were reviewed in this study and meaningful conclusion could be drawn. OUTCOMES The mean age at diagnosis of secondary skin dermatoses after NBUVB therapy was 62.08 years with a male to female ratio of 2:1. The cases were reported more in Europeans than in Asians (2.75:1), and the Fitzpatrick skin type was mainly Ito III (12/15). The mean cumulative number and cumulative dose of UVB treatments were 43.71 and 42, 400 (mJ/cm), respectively. There was a positive relationship between Fitzpatrick skin type and cumulative dose of UVB treatments. Among the secondary skin diseases after NBUVB treatment, 12 were tumors, 2 were non-tumorous dermatoses. Only our patient presented with both. By polymerase chain reaction-single nucleotide polymorphism (PCR-SNP) analysis, C-G mutation of exon 4 of p53 was found in AK and MF specimens in our patient. CONCLUSION To our knowledge, our case is the first MF patient accompanied with AK, AK with SCC transformation and Porokeratosis after NBUVB treatment. Lower Fitzpatrick skin type may be the risk factor of secondary skin diseases after NBUVB treatment.