RESUMO
BACKGROUND: Sweet's syndrome, also known as acute febrile neutrophilic dermatosis, is a rare skin disorder that may be associated with cancer. CASE SUMMARY: A 58-year-old female presented with a cholestatic syndrome and significant weight loss three months before admission. Five months earlier, she had abruptly developed skin lesions with erythematous papules that evolved to erythematous blisters. Clinical evaluation and laboratory tests confirmed hepatic cholangiocarcinoma. Skin lesions histopathological findings showed neutrophilic dermatosis, massive edema, fibrin, necrosis, and elastosis. These results, in association with the macroscopic aspects of the findings, led to the diagnosis of paraneoplastic Sweet's syndrome due to cholangiocarcinoma. As staging was consistent with an advanced tumor without a cure perspective, we opted to perform percutaneous biliary drainage, and subsequently, palliative care. Eventually, after a few weeks, the patient died. CONCLUSION: In conclusion, the diagnosis of the underlying disease-causing Sweet's syndrome must be accurate, and patients need to be followed-up, as neoplasia such as cholangiocarcinoma may be a later manifestation.