Castleman's disease masquerading as an adrenal tumor.

Abstract

Castleman’s disease is a rare disorder characterized by benign proliferation of lymphoid tissues. Most cases occur as mediastinal masses, although extrathoracic involvement, including nodal and extra nodal locations, has been reported. The pararenal location of localized disease may sometimes be mistaken for adrenal or renal tumor. We report on a 25-year-old male with Castleman’s tumor located superomedially to the upper pole of the right kidney mimicking the suprarenal mass. CASE REPORT A 25-year-old man underwent abdominal ultrasonography for vague upper gastrointestinal tract symptoms and was found to have a 6 8 cm. mass in the right suprarenal area. Computerized tomography (CT) revealed a calcified lesion in the region of the adrenal gland, and the latter was not separately identifiable (fig. 1). Pulse and blood pressure were normal. Renal function tests, serum cortisol, electrolytes and urinary catecholamines were all normal. Preliminary diagnosis was nonfunctioning adrenal tumor. The patient underwent exploration through the bed of the 11th rib via an extrapleural transperitoneal approach. There were 2 lobulated masses in the suprarenal area, which were carefully dissected and separated from the inferior vena cava and excised. Histopathological analysis demonstrated Castleman’s disease (hyaline vascular type) and the adrenal gland itself was histologically unremarkable (fig. 2). DISCUSSION Castleman’s disease (giant lymph node hyperplasia) is a rare heterogeneous lymphoproliferative disorder of unknown cause and pathogenesis. The most common locations are the thorax (63%), abdomen (11%) and axilla (4%). To date, only 6 cases of Castleman’s disease in relation to the upper urinary tract have been described in the world literature.1–3 Castleman’s disease is infrequently associated with various immunological abnormalities or subsequent development of malignancy such as Kaposi’s sarcoma, malignant lymphoma and plasmacytoma. Three histological variants (hyaline vascular, plasma cell and mixed) and 2 clinical types (solitary and multicentric) of disease have been described. The disease may occur in almost any area in which lymph nodes are normally found. Diagnostic imaging methods such as ultrasound and CT or magnetic resonance imaging cannot identify Castleman’s tumor due to the lack of tumor specific signs, but these tests yield important information concerning exact tumor location. Only surgical resection and conventional histological evaluation give an accurate characterization of this tumor. Localized forms are usually benign, whereas multicentric forms may be aggressive. The localized variants (solitary lesions) respond well to surgical excision.3 Unlike localized disease, for which surgical excision is curative regardless of histological type, multicentric disease often necessitates aggressive systemic therapy and portends a poorer outcome. In our case the Castleman’s tumor was located superomedially to the upper pole of the right kidney, mimicking a suprarenal mass. Castleman’s disease should be considered a benign retroperitoneal lesion in the evaluation of pararenal masses.