Discussion
To our knowledge, there has no previous review of literature reporting on mediastinal cystic teratoma with pleural effusion. We find that mature teratoma with pleural effusion presented a high proportion in female patients during their young adult life. However, the literature search demonstrates the occurrence of mature teratoma with pleural effusion in patients as young as at 25 weeks of gestation and as old as 51 years.9–62 Respiratory symptoms are predominant and not specific which has led often to a delay in the diagnosis for as long as 2 years.9–11,19,20,22,28,30,32–61 The majority of studies were reported in high-income countries. The requirement for the diagnosis to be made by CT scan and histopathology might explain the fact that such diagnosis is mostly reported in high-income countries. Tissues found in the tumour appeared mostly immature and of ovarian and pancreatic origin. Except from cases that presented complications, the duration of hospitalisation was short with variable lengths of follow-up periods. Complications related to infections and metastases were reported in less than 10 cases. Relapses occurred for some cases and death was a rare outcome and was reported in 10 cases due to respiratory complications essentially.17,22,24,32
The major strength of our study is the systematic search of the literature and the number of the cases reported. This will allow a more systematic assessment of the prevalence of the disease and could raise awareness among clinician from low and middle-income countries in particular. Our results have highlighted a substantial proportion of cases from low-income settings. Ascertainment misclassification following difficulties to diagnose mediastinal cystic teratoma might preside on the wrong impression of its rarity in poor settings. Regarding the high burden of respiratory infection diseases in such a region, clinicians might consider mediastinal tumours after an attempt to treat an infection disease not specified otherwise.
Although a systematic search of literature through Medline, among limitations of our study are the non-systematic search of ≥3 databases and the exclusion of studies without full-texts. Another limitation was related to the nature of the study that reported only on cases thus not representative of the populations from which the cases came from. However, the review has highlighted the need to consider such a differential diagnosis when assessing a patient with signs of pleural effusion especially in early childhood or young adult life.