Unusual presentation of endometriosis as a large tubo-ovarian abscess posing a diagnostic challenge.

Tubo-ovarian abscess (TOA) is a severe complication of pelvic inflammatory disease (PID), but it can also occur in women without prior PID or sexually transmitted infections. Recent studies suggest that endometriosis may increase the risk and severity of TOA due to factors such as invasive procedures and the presence of endometriomas, which provide a favourable environment for infection. We report a rare case of an elderly nulligravida who presented with acute abdominal pain and fever. Surgical exploration confirmed TOA involving an endometrioma. The patient underwent pus drainage followed by right salpingo-oophorectomy and appropriate antibiotic therapy, with complete recovery. This case highlights the rare association between endometriosis and TOA, emphasising the need for clinicians to consider this diagnosis in women with endometriosis presenting with acute pelvic symptoms, even in the background of treated genital tuberculosis. Early recognition and prompt surgical management are crucial for reducing morbidity.