A rare case of unicentric Castleman disease in the posterior mediastinum: case report and integrated literature review.

BACKGROUND: Castleman disease (CD) is a complex lymphoproliferative disorder characterized by nonspecific clinical manifestations and imaging features. When occurring within the mediastinum, it is easily confused with other diseases, posing diagnostic challenges. We report a case of unicentric hyaline vascular Castleman disease (UCD) located in the posterior mediastinum. This case report is supplemented by a retrospective analysis of the literature, aiming to enhance understanding and improve diagnostic accuracy for this condition.

CASE SUMMARY: This paper provides a detailed account of the clinical data, imaging findings, diagnostic and therapeutic process of a 28-year-old female patient with a posterior mediastinal UCD. Seven years ago, the patient incidentally found a left posterior mediastinal mass during an outpatient visit for a respiratory tract infection at another hospital. A needle biopsy at that time suggested post-infectious reactive lymphadenopathy. After antimicrobial therapy, respiratory symptoms improved, but intermittent back pain subsequently occurred without prompt attention and follow-up. The patient recently presented for follow-up due to persistent left-sided chest pain unresponsive to analgesics. Imaging examination revealed a significantly enlarged lesion compared to previous findings, now extending to the left thoracic ninth intervertebral foramen region. Additionally, localized increased bone density was observed adjacent to the ninth rib. The patient ultimately underwent complete surgical resection, with postoperative pathology confirming hyaline vascular Castleman disease. No adjuvant radiotherapy or chemotherapy was administered postoperatively.

CONCLUSION: The definitive diagnosis of posterior mediastinal hyaline vascular type CD relies on histopathological examination of surgically resected specimens combined with immunohistochemical staining to establish diagnosis and classification. Imaging features of a hyper-vascular mass in the posterior mediastinum, exhibiting persistent marked enhancement with peri- and intra-tumoral tortuous feeding vessels, may provide valuable diagnostic clues for this disease. Radiologists and relevant clinicians should enhance the recognition of this entity to facilitate the formulation and optimization of diagnostic and therapeutic strategies.