When peritoneal tuberculosis mimics advanced ovarian cancer: A laparoscopic case from an endemic region.

A 28-year-old woman with no significant medical or surgical history was referred to our gynecology department with a three-month history of intermittent generalized abdominal pain, fever, anorexia, and weight loss, without accompanying diarrhea or vomiting. She denied experiencing night sweats or cough. Her family history was unremarkable for malignancy, chronic illnesses, or tuberculosis. On clinical evaluation, the patient exhibited a BMI of 22 kg/m² and was febrile, with a pulse rate of 86/min and blood pressure measured at 120/80 mmHg. There were no signs of pallor, jaundice, cyanosis, or lymphadenopathy. Cardiovascular and respiratory assessments revealed no abnormalities. Abdominal examination showed mild distension with a soft consistency and the presence of ascites on percussion, though no organ enlargement was identified. Pelvic examination revealed a retroverted uterus with limited mobility and a palpable fullness in the left fornix. Laboratory investigations revealed hemoglobin (Hb) at 10.7 g/dL, a white blood cell (WBC) count of 7.2 × 10⁹/L, and a C-reactive protein (CRP) level of 30 mg/L. Serum electrolytes, renal function tests (RFTs), and liver function tests (LFTs) were within normal limits. Human chorionic gonadotrophin (HCG) test was negative. Total protein was 60 g/L, albumin 34 g/L, and lactate dehydrogenase (LDH) 490 U/L. Blood cultures were sterile, and Wright's and Widal tests were negative. Chest X-ray findings were unremarkable. The Mantoux Tuberculin Skin Test and HIV screening test were negative. A significantly elevated serum CA-125 level of 790 U/mL was identified, while other tumor markers, including CA 19-9, alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), were within normal limits. Abdominopelvic ultrasound (US) revealed a complex hypoechoic mass in the left adnexa measuring 50 × 60 mm, while the right ovary and uterus appeared normal. Moderate fluid accumulation was noted in the pouch of Douglas. Computed tomography (CT) confirmed the presence of moderate peritoneal effusion, micronodular thickening of the peritoneal lining, and a left adnexal mass measuring 5 × 5 cm. Magnetic resonance imaging (MRI) further detailed a large intracavitary effusion, thickened peritoneum scattered with multiple nodules showing inflammatory enhancement, and a left adnexal mass measuring 6 cm ( Fig. 1 ). Fig. 1 The T1 FAT SAT Sequence of abdominopelvic MRI post-gadolinium injection: Ascites (arrow), Peritoneal nodules (asterisk), Left adnexal cystic mass measuring 6 cm (circle). Fig 1 The T1 FAT SAT Sequence of abdominopelvic MRI post-gadolinium injection: Ascites (arrow), Peritoneal nodules (asterisk), Left adnexal cystic mass measuring 6 cm (circle). The clinical presentation, radiological findings, and laboratory results led us to hypothesize peritoneal tuberculosis, peritoneal carcinomatosis, or advanced ovarian cancer as potential diagnoses. To establish a definitive diagnosis, exploratory laparoscopy was performed. Approximately 2 liters of ascitic fluid were identified, along with numerous small nodules (1-2 cm) distributed across the uterus, ovaries, fallopian tubes, omentum, intestinal loops, and peritoneal surfaces ( Fig. 2 ). A cystic lesion was also noted in the left adnexa. Ascitic fluid was aspirated for cytological analysis, and multiple peritoneal biopsies were obtained. Cytological examination showed no evidence of malignant cells, while histopathological analysis confirmed necrotizing granulomatous inflammation, consistent with tuberculosis ( Fig. 3 , Fig. 4 ). Fig. 2 Laparoscopic view showing a frozen pelvic: the pelvic cavity, the uterus and adnexa, covered with numerous small, millet-shaped nodules and thin adhesions distributed throughout. Fig 2 Fig. 3 HEx200: Epithelioid and giganto-cellular granuloma showing caseous type necrosis. Fig 3 Fig. 4 HEx400: Langhans type multinucleated giant cell. Fig 4 Laparoscopic view showing a frozen pelvic: the pelvic cavity, the uterus and adnexa, covered with numerous small, millet-shaped nodules and thin adhesions distributed throughout. HEx200: Epithelioid and giganto-cellular granuloma showing caseous type necrosis. HEx400: Langhans type multinucleated giant cell. Despite negative Ziehl–Neelsen staining, tuberculosis (TB) remained the most probable diagnosis. Confirmation was achieved through conventional TB polymerase chain reaction (TB-PCR) performed on paraffin-embedded tissue. The patient was enrolled in the DOTS (Directly Observed Treatment Short Course) protocol under the Tunisian National Tuberculosis Control Program and initiated on a short course 6-month antitubercular therapy (ATT) regimen. The treatment included isoniazid (10 mg/kg), rifampicin (15 mg/kg), pyrazinamide (35 mg/kg), and ethambutol (20 mg/kg) daily for the first two months, followed by a continuation phase of isoniazid and rifampicin at the same doses for the remaining four months. Follow-up evaluations were uneventful, with complete resolution of the adnexal cyst and ascites observed on subsequent ultrasounds, accompanied by a weight gain of 3 kilograms.

Complete written informed consent was obtained from the patient for the publication of this study and accompanying images.

Physicians should consider peritoneal tuberculosis as a differential diagnosis in young women from endemic regions presenting with adnexal masses, ascites, and elevated CA-125 levels. However, advanced ovarian cancer must remain the primary diagnosis due to its higher prevalence and differing treatment approach. While peritoneal tuberculosis can be managed with antitubercular therapy, ovarian cancer requires surgical intervention and often chemotherapy. Laparoscopy is the gold standard for distinguishing between these conditions, offering direct visualization of the peritoneal cavity and enabling biopsy collections for histopathological confirmation. By utilizing minimally invasive techniques, unnecessary laparotomies and major surgeries can be avoided, ensuring an accurate and timely diagnosis.

Peritoneal tuberculosis (PT) is one of the most frequently affected sites in cases of extra-pulmonary tuberculosis, accounting for approximately 4% of such cases [ 8 ]. In recent years, its relevance has grown due to the resurgence of HIV infection. In 2022, the Global Tuberculosis Report estimated that 10.6 million people worldwide were diagnosed with tuberculosis (TB) [ 9 ]. Tunisia, classified as a country with intermediate endemicity, reported an incidence of 29 cases per 100,000 inhabitants in 2017 [ 10 ]. PT predominantly affects young women, with a mean age of 28-37 years, as observed in our case. It typically results from the rupture of infected mesenteric lymph nodes or the contiguous spread of Mycobacterium tuberculosis from intestinal, digestive, or pulmonary lesions. Notably, the primary pulmonary focus often resolves completely, leaving no clinical or radiological signs [ 11 , 12 ]. The chest X-ray was normal in our case, consistent with literature indicating that up to 40% of PT cases exhibit no abnormalities on chest radiographs [ 13 ]. PT presents in two forms: the ascitic form, which is the most common (95%) and was observed in our case, and the less common “dry fibro-adhesive” form, accounting for 5% of cases [ 14 , 15 ]. Symptoms are often nonspecific and include fatigue, low-grade fever, abdominal pain and distension, loss of appetite, and weight loss, mimicking the clinical presentation of advanced ovarian malignancy [ 16 ]. Radiological findings such as ascites, omental thickening, and peritoneal nodules on ultrasound, CT, and MRI are frequently reported in PT. However, these findings are not definitive and often overlap with the radiological appearance of advanced ovarian malignancy, as seen in our case [ 17 ]. Elevated CA-125, a nonspecific tumor marker, is another diagnostic challenge. While it is often elevated in PT, endometriosis, pelvic inflammatory disease (PID), and ovarian malignancy [ 16 ], high levels as noted in our case, are generally more indicative of malignancy [ 18 ]. Despite its lack of specificity, CA-125 can serve as a prognostic marker once a definitive diagnosis is established and treatment initiated [ 19 ]. Several diagnostic tools are available for PT. Isolation of Mycobacterium tuberculosis from ascitic fluid is reliable but requires a culture period of 3-4 weeks [ 20 ]. More rapid tests include measurement of adenosine deaminase (ADA) levels in ascitic fluid, with a sensitivity of 96% and specificity of 98% [ 21 , 22 ], and Polymerase Chain Reaction (PCR), which detects Mycobacterium tuberculosis within 24-48 h, with sensitivities ranging from 60% to 80% and specificity of 96% [ 23 ]. Interferon-gamma release assays, such as QuantiFERON, are particularly useful for latent TB diagnosis, with 93% sensitivity and 99% specificity [ 24 ]. However, these advanced techniques are often costly and not consistently accessible in resource-limited settings like Tunisia. Due to the lack of specific laboratory or imaging findings to differentiate PT from advanced ovarian cancer, histopathological confirmation is critical. Laparoscopy remains the gold standard for diagnosing PT, offering direct visualization and biopsy sampling with a sensitivity of 93% and specificity of 98% [ 5 , 25 ]. Studies underscore the importance of histopathological analysis in avoiding unnecessary surgical interventions, as PT is managed medically through antitubercular therapy (ATT) [ 16 , 26 ]. Macroscopic findings in PT include peritoneal nodules in 76%-100% of cases. These nodules are typically whitish, millimetric (0.5-2 mm), and evenly distributed across the parietal and visceral peritoneum, as observed in our laparoscopy. Secondary findings include peritoneal adhesions and inflammation [ 27 , 28 ]. Microscopically, PT is characterized by confluent granulomas composed of epithelioid cells, a peripheral lymphocytic zone, and Langhans giant cells with central caseous necrosis, consistent with our case [ 29 ]. Given the endemic nature of TB in Tunisia, our patient's clinical presentation, radiological findings, and laparoscopy strongly suggested PT. However, the overlap with features of advanced ovarian cancer necessitated histopathological confirmation to rule out malignancy definitively. The treatment of PT in Tunisia follows the National Tuberculosis Control Program, established in 1978. It adheres to the “short-course” ATT regimen, consisting of a 2-month intensive phase with isoniazid, rifampicin, pyrazinamide, and ethambutol (or streptomycin), followed by a 4-month continuation phase with isoniazid and rifampicin alone [ 30 ].

Tuberculosis remains a significant public health issue in developing countries, particularly in Tunisia, where its incidence has been rising in recent years. Globally, approximately one-third of the population is infected with Mycobacterium tuberculosis, leading to 8-10 million new cases and 3 million deaths annually [ 1 ]. Peritoneal tuberculosis, while rare, accounts for 0.1%-4% of all tuberculosis cases and poses considerable diagnostic challenges [ 2 ]. The diagnostic difficulty arises from the nonspecific nature of its clinical manifestations and the limited sensitivity of biological and radiological investigations. Common clinical symptoms include dull abdominopelvic pain, menstrual disturbances, and infertility [ 3 ]. Imaging findings often reveal adnexal masses, ascites, and peritoneal thickening or nodules [ 4 ]. Additionally, elevated CA-125 levels may mimic those seen in advanced ovarian cancer, further complicating the differentiation between these conditions [ 5 ]. Advanced diagnostic methods, such as Polymerase Chain Reaction (PCR) and Adenosine Deaminase (ADA) measurement, can improve diagnostic accuracy. However, these techniques are often unavailable or not routinely implemented, especially in resource-limited settings [ 6 ]. A definitive diagnosis requires the identification of Mycobacterium tuberculosis in clinical samples, such as sputum, pus, or tissue biopsies [ 7 ]. Exploratory laparoscopy with biopsy remains the gold standard for diagnosing peritoneal tuberculosis, offering high specificity (93%) and sensitivity (98%) [ 5 ]. This report outlines our experience in diagnosing a case of peritoneal tuberculosis that closely mimicked advanced ovarian carcinoma, utilizing laparoscopic evaluation to achieve accurate histological confirmation.