Work

Case Report: Diagnostic dilemma: rebound thymic hyperplasia mimicking mediastinal relapse following chemoimmunotherapy in pediatric jejunal Burkitt lymphoma

Year: 2026

Type: article

Abstract: Background: Pediatric sporadic Burkitt lymphoma (BL) typically presents with gastrointestinal involvement; primary mediastinal disease is exceedingly rare. Rebound thymic hyperplasia (RTH) is a benign regenerative process following chemotherapy that can radiologically mimic mediastinal relapse, creating significant diagnostic challenges in post-treatment surveillance. Case presentation: An 8-year-old male was diagnosed with St. Jude stage III Burkitt lymphoma (BL) following the emergency resection of a jejunal mass. After receiving risk-adapted chemoimmunotherapy, he achieved a complete metabolic response. Three months post-treatment, routine surveillance computed tomography (CT) revealed a new anterior mediastinal soft tissue mass, magnetic resonance imaging (MRI) revealing T2 hyperintensity in the anterior mediastinal lesion without restricted diffusion, while subsequent PET/CT demonstrated mildly increased FDG uptake, raising immediate clinical concern for disease relapse. To rule out malignancy, a CT-guided percutaneous biopsy was performed. Histopathological analysis revealed normal thymic microarchitecture containing Hassall's corpuscles. The final imaging and pathological findings supported a diagnosis of chemotherapy-induced rebound thymic hyperplasia (RTH). Conclusion: Cytotoxic therapy induces profound thymic involution, often followed by striking regenerative expansion upon treatment cessation. Recognizing RTH is paramount to avoid misdiagnosing neoplastic recurrence and administering unwarranted therapies. This case highlights need to integrate advanced imaging and tissue biopsy when evaluating new mediastinal opacities in pediatric lymphoma survivors.

Source: Frontiers in Immunology

DOI: 10.3389/fimmu.2026.1910294

Authors: Meifang Lin, Zengwang Zhang, Hao Zhang, Dongdong Zhang

Institutions: Hubei University of Medicine, Xiang Yang No.1 People's Hospital, Hubei University of Arts and Science, Xiangyang Central Hospital

Language: English

Topic: Lymphoma Diagnosis and Treatment

Subfield: Pathology and Forensic Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,801