Intracystic septal biopsy in a multilocular pelvic cyst-A case report.

Aspiration combined with sclerotherapy is widely used for the management of pelvic cystic lesions in patients who are not suitable for surgery. However, the lack of histological confirmation remains a major limitation, particularly in multilocular cysts without solid components. We report a case of a 42-year-old woman with a multilocular pelvic cystic lesion. Imaging suggested a mucinous tumor, while tumor markers were unremarkable. The patient underwent ultrasound-guided aspiration and sclerotherapy. During the procedure, biopsy targeting intracystic septa was performed. Histopathological examination unexpectedly revealed intestinal mucosa and smooth muscle tissue, indicating that the presumed septa originated from adherent bowel rather than true intracystic structures. The patient recovered uneventfully without procedure-related complications, and no recurrence was observed during follow-up. Intracystic septal biopsy extends the conventional approach of sampling solid components to intracystic structures, providing a potential strategy for obtaining histological diagnosis in cysts lacking solid nodules. This case demonstrates the technical feasibility of this approach. However, it also highlights that imaging-defined septa may not correspond to true intracystic anatomy, especially in patients with prior surgery or inflammatory conditions. Intracystic septal biopsy may serve as a complementary tissue acquisition strategy in multilocular cystic lesions. Careful evaluation of anatomical context is essential to minimize the risk of misinterpretation and procedural complications.