Tuberculous Infection of a Posterior Mediastinal Neuroenteric Cyst Presenting as Secondary Autoimmune Hemolytic Anemia: A Case Report.

Childhood tuberculosis (TB) can present with atypical and rare manifestations, posing significant diagnostic challenges. While mediastinal masses in children are frequently malignant, congenital cysts can become secondarily infected. Furthermore, TB is a rare but recognized cause of secondary autoimmune hemolytic anemia (AIHA). We present the case of a four-year-old partially vaccinated boy from Lahore who presented with a four-month history of low-grade fever, progressive pallor, and jaundice. Clinical examination revealed severe pallor, icterus, and hepatosplenomegaly. Laboratory investigations confirmed a Coombs-positive hemolytic anemia. Imaging revealed a large cystic lesion in the posterior mediastinum with vertebral anomalies, initially raising suspicion for a malignancy. The patient underwent surgical excision of the cyst, which yielded purulent fluid. Histopathology confirmed a neuroenteric cyst with chronic granulomatous inflammation and necrosis. The patient was initiated on anti-tuberculous therapy (ATT), resulting in rapid clinical and hematological improvement. This case highlights an extremely rare triad of a congenital neuroenteric cyst, secondary TB infection, and AIHA. In TB-endemic regions, a high index of suspicion must be maintained for atypical presentations of TB, including superinfection of congenital anomalies and unusual hematological complications. Multidisciplinary coordination is vital for accurate diagnosis and management.