Diagnostic Utility of Laparoscopy in Breast Cancer-Associated Carcinomatous Peritonitis With Suspected Advanced Ovarian Cancer.

Carcinomatous peritonitis (CP) secondary to breast cancer is an uncommon metastatic manifestation that presents considerable diagnostic challenges, particularly when the primary lesion is not detectable through imaging modalities. This report examines the case of a 54-year-old female patient who presented with abdominal pain and constipation. Initial preoperative imaging and tumor marker analysis suggested gynecological malignancy, with a strong suspicion of ovarian cancer; however, no definitive primary tumors were identified. Subsequent diagnostic laparoscopy revealed peritoneal dissemination, and histopathological examination confirmed metastatic breast cancer via immunohistochemical staining. This case highlights the essential role of laparoscopy in obtaining a pathological diagnosis even when gynecological cancer is suspected. Laparoscopy is a minimally invasive and highly effective diagnostic tool for CP, even in cases where the primary breast lesion remains undetected. Early consideration of breast cancer in differential diagnosis may facilitate timely and accurate diagnosis, thereby enabling appropriate management of the condition.