特發性多中心型卡斯特曼氏病(Castleman disease) 模仿轉移性腎盂尿路上皮癌：

游家豪¹、許軒豪¹

¹臺北市立萬芳醫院泌尿科－委託臺北醫學大學辦理

Idiopathic Multicentric Castleman Disease Mimicking Metastatic Urothelial Carcinoma of the Renal Pelvis: A Rare Case and Literature Review

Chia-Hao, You¹, Syuan-Hao Syu ¹

¹Department of Urology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.

Introduction:

Idiopathic Multicentric Castleman Disease (iMCD) is a rare and underdiagnosed lymphoproliferative disorder characterized by systemic inflammation, lymph node enlargement, and multiple organ involvement. Unlike other types of multicentric Castleman disease (MCD), iMCD is not associated with known viral causes like human herpesvirus 8 (HHV-8) and often requires distinguishing from infectious, malignant, and autoimmune diseases

Presentation of case:

We report the case of a 44-year-old male patient without underlying disease who presented with intermittent left flank pain for 1–2 months. Initial abdominal and pelvic CT imaging revealed a soft tissue lesion at the renal pelvis and irregular wall enhancement of the upper ureter, accompanied by diffuse lymph node enlargement in the peri-ureteral, para-aortic, and bilateral inguinal regions. Suspected of advanced urothelial carcinoma of the renal pelvis with lymph node invasion, the patient was admitted for the endoscopic biopsy, which revealed chronic inflammation on pathology. However, the follow-up abdominal CT three months later showed no interval change. Consequently, the excisional biopsy of the left inguinal lymph nodes was performed, with pathology confirming Castleman disease of mixed hyaline vascular and plasma cell variant. Immunostaining for Human Herpesvirus-8 (HHV-8) was negative.

Discussion and conclusion:

 Multicentric Castleman disease (MCD) is often asymptomatic or presents without systemic symptoms. Patients with MCD display varied clinical features; however, common findings include generalized lymphadenopathy, hepatomegaly, and splenomegaly. Diagnosing idiopathic MCD (iMCD) requires meeting specific clinical, laboratory, and histopathological criteria. Major diagnostic criteria include multicentric lymphadenopathy (≥1 cm in short-axis diameter in ≥2 lymph node stations) and characteristic lymph node histopathology. For minor criteria, which encompass laboratory and clinical findings, a diagnosis requires meeting ≥2 minor criteria, with at least one being laboratory-based. As a diagnosis of exclusion, iMCD requires ruling out infections, autoimmune diseases, and malignancies.

Currently, the IL-6 antagonist siltuximab is the only FDA-approved treatment for iMCD, with patients exhibiting laboratory evidence of inflammatory syndrome often deriving greater benefit from this therapy. Accurate and timely diagnosis and treatment are crucial for improving overall prognosis.