Aim:
to evaluate the possibilities and advantages of diagnostic laparoscopy over non-invasive research methods in case of differences in diagnoses in different studies.

Material and methods:
Female patient was hospitalized in the surgical of the Municipal Enterprise “2nd City Clinical Hospital of Poltava City Council” (Poltava, Ukraine) in 2023. The patient underwent a complete general clinical examination, a plain radiograph of the abdominal cavity, fibrogastroduodenoscopy, colonoscopy, ultrasound of the abdominal organs, CT scan of the abdominal organs. Diagnostic laparoscopy was performed to make a final diagnosis.

Results:
A plain radiography of the abdominal cavity revealed no pathology. Ultrasound of the abdominal organs revealed a pelvic mass. A computed tomography scan revealed damage to the pelvic organs in the form of a neoplasm and an enlargement of the left ovary. The preliminary diagnosis was a pelvic tumor, tumor of the left ovary. Diagnostic laparoscopy was performed to make the diagnosis. A rounded formation was defined in Douglas space. The capsule of the formation was opened and pus was released. The abscess wall was opened, and a foreign body (gauze pad) was removed from the cavity. The patient was discharged from the hospital in satisfactory condition on the fifth day after surgery.

Conclusions:
The case we examined emphasizes that when assessing the nature of an intra-abdominal neoplasm, it is necessary to remember about foreign bodies, especially in patients after surgical interventions. Diagnostic laparoscopy is a technically advanced and minimally invasive procedure for the diagnosis and treatment of intra-abdominal gossypiboma.