Case Report: Paraneoplastic melanoma-associated retinopathy mimicking posterior uveitis.

Stevens-Johnson syndrome (SJS) is a severe mucocutaneous disorder characterized by widespread epidermal necrosis and mucosal involvement. It presents with fever, malaise, and rapidly spreading exudative erythematous lesions of varying sizes throughout the body, which makes it an important differential diagnosis of fever and rash. A delayed-type hypersensitivity reaction underlies the disease, with cytotoxic T cells and related immune mechanisms playing a central role in keratinocyte apoptosis. Furthermore, epidermal detachment in SJS involves less than 10% of the body surface area, whereas it involves more than 30% of the body surface area in toxic epidermal necrolysis (TEN). Although rapidly progressive epidermal detachment is known to cause blisters, pustular lesions are rare in SJS. Given that SJS and TEN are potentially fatal conditions having a 1-year mortality rate of 24% and 49%, respectively, prompt diagnosis and appropriate treatment are essential []. We herein report a case of SJS presenting with pustular lesions, which was diagnosed by exclusion on the basis of histopathological findings in a timely manner, allowing appropriate treatment to be administered. A 25-year-old male patient with no significant medical history or regular medication presented to the emergency department with a fever and rash. The fever had developed 7 days before the current presentation and was followed 4 days later by lip swelling, conjunctival hyperemia, and sore throat, which caused difficulty with oral intake. Tests by the local public health authority were negative for measles and rubella. Two days before presentation, a generalized rash and dysuria developed, prompting evaluation at our hospital. The patient denied upper respiratory and gastrointestinal symptoms. The skin findings revealed multiple, 3-mm pustules surrounded by erythema on the face, chest, and back, which in some areas coalesced into vesicles of up to 1 cm in diameter (). shows the patient’s back 3 days after admission. Scattered erosions were observed over less than 10% of the body surface, including the distal extremities, lips (), buccal mucosa (), and genital area. Mild, corneal erosions were observed, and the conjunctivae displayed marked pseudomembrane formation (). There was no loss of visual acuity, visual field impairment, or ocular pain. The patient had no significant medical history, regular medications, or known allergies. After the onset of the rash, he received acetaminophen, loxoprofen, and rebamipide. Laboratory tests revealed a C-reactive protein level of 28.4 mg/dL (reference range: < 0.14 mg/dL), a normal white blood cell count, and unremarkable hematological, biochemical, coagulation, and infectious disease test findings (). Autoimmune tests for anti-desmoglein 1, anti-desmoglein 3, and anti-BP180 antibodies were negative. Urinalysis initially indicated pyuria. Blood and urine cultures returned negative, and chest radiography revealed no abnormalities.