Histopathology of peritonitis due to infectious mononucleosis with background Chlamydia trachomatis infection: A case report and literature review

• Published in: Pathology international Vol. 74; no. 10; pp. 611 - 617
• Main Authors: Kaimi, Yuto, Naka, Tomoaki, Yoshida, Hiroshi, Uno, Masaya, Maeshima, Akiko Miyagi
• Format: Journal Article
• Language: English
• Published: Australia Wiley Subscription Services, Inc 01.10.2024
• Subjects: Adenocarcinoma; Ascites; Biopsy; Cancer; Chlamydia; Chlamydia trachomatis; Computed tomography; Cytology; Diagnosis; Differential diagnosis; Distension; Enzymes; Epstein-Barr virus; Fallopian tube; Fatigue; Fatigue tests; Histopathology; Immunoglobulin M; Immunohistochemistry; Inclusion bodies; Infections; Infectious mononucleosis; Laparoscopy; Literature reviews; Liver; Lymphadenopathy; Lymphocytes; Lymphocytes B; Lymphocytosis; Mononucleosis; Peritoneum; Peritonitis; Polymerase chain reaction; Secretions; Serological tests; Sexually transmitted diseases; STD; histopathology; peritoneum; ascites; Epstein–Barr virus; infectious mononucleosis
• DOI: 10.1111/pin.13469
• ISSN: 1320-5463; 1440-1827

Epstein–Barr virus (EBV) is a major cause of infectious mononucleosis (IM), characterized by fever, fatigue, sore throat, lymphadenopathy, atypical lymphocytosis, and elevated liver enzymes. However, ascites is a rare complication associated with IM. We present a rare case of IM with ascites and peritonitis in a patient who underwent a peritoneal biopsy. A 20‐year‐old woman presented with fatigue and abdominal distension. Laboratory examination revealed atypical lymphocytes in peripheral blood (54%) and elevated liver enzymes. EBV serological tests revealed a recent primary infection (EBV VCA IgM 1:160). Computed tomography revealed moderate ascites and peritonitis. Adenocarcinoma was suspected based on the ascites' cytology. Considering possible complications of IM and adenocarcinoma, a laparoscopic biopsy was performed. Histological findings of biopsy specimens from the peritoneum, omentum, and fimbria of the fallopian tube demonstrated severe inflammatory cell infiltration and focal aggregation of large EBV‐encoded RNA‐1 (EBER1)‐positive B cells, mimicking EBV‐positive polymorphous B‐cell lymphoproliferative disorder. Furthermore, intracytoplasmic inclusion bodies of Chlamydia trachomatis were observed by immunohistochemistry. Real‐time polymerase chain reaction detected C. trachomatis in cervical secretions. Two months after laparoscopy, ascites decreased, and the diagnosis was IM‐associated peritonitis with C. trachomatis infection. IM should be considered as a differential diagnosis in young patients with ascites. We reported a 20‐year‐old female case of infectious mononucleosis with ascites and peritonitis in a patient with Chlamydia trachomatis infection. Histological findings in biopsy specimens from the peritoneum, omentum, and fimbria of the fallopian tube demonstrated EBV‐positive polymorphous B‐cell lymphoproliferative disorder compatible with infectious mononucleosis. Co‐infection with C. trachomatis may have contributed to the deterioration of peritonitis and salpingitis caused by infectious mononucleosis.