RESUMO
BACKGROUND: Abdominal wall Actinomycosis is a rare disease associated with the use of intrauterine device and as a complication of abdominal surgery. Diagnosis is difficult because it is unusual and behaves like a malignant neoplasm. AIM: A case report is presented of a patient who had used an intrauterine device for four years and developed a stony tumour in the abdominal wall associated with a set of symptoms that, clinically and radiologically, was simulating a peritoneal carcinomatosis associated with paraneoplastic syndrome, even in the course of an exploratory laparotomy. CLINICAL CASE: The patient attended our hospital with a two-month history of abdominal pain and symptoms that mimic a paraneoplastic syndrome. The diagnosis of abdominal actinomycosis was suspected by the finding of the microorganism in cervical cytology together with other cultures and Actinomyces negative in pathological studies, confirming the suspicion of a complete cure with empirical treatment with penicillin. CONCLUSIONS: Actinomycosis should be considered in patients with pelvic mass or abdominal wall mass that mimics a malignancy. Antibiotic therapy is the first treatment choice and makes a more invasive surgical management unnecessary.