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A 57 year old nonhypertensive male presented with vague abdominal pain since 3–4 years Routine hematology and blood biochemistry were normal. The 24-hour urinary metanephrine and normetanephrine levels were within normal limits; the chest x-ray was normal. Computed tomography (CT) scan of abdomen showed a 9.6 × 6.0 × 6.7 cm3 heterogeously enhancing lesion in the retroperitoneum between the left kidney and the aorta. The lesion had specks of calcification and the fat planes were preserved. There was another 4.6 × 4.1 × 5.0 cm3 heterogeneously enhancing space occupying lesion in the pelvic cavity medial to the right internal iliac artery [Figure 1]. A definite preoperative diagnosis could not be made. He underwent exploration with excision of both the retroperitoneal tumors. There was a 9 × 7.5 × 3.5 cm3 thick oval mass posterior to the left kidney and another 6 × 7 cm2 mass in the pelvis, between the external and the internal iliac vessels. On section, they were well encapsulated, tan colored, and fleshy with minute spaces. Histopathology of both the masses was similar and revealed masses of disordered lymphoid tissue with compressed sinuses and many small regressively transformed follicles surrounded by concentric rings of small lymphocytes [Figure 2]. The follicles contained whorls of follicular dendritic reticulum cells with central hyalinized blood vessels perforating the follicles. A diagnosis of hyaline-vascular type of CD was made on both the masses. The patient had an uneventful postoperative recovery and is doing well without any signs of recurrence after two years of follow-up.
CD is a rare lymphoid disorder characterized by lymphoid and vascular proliferation. There is no age and sex predilection.
It is classified as localized unicentric form and multicentric generalized forms based on radiologic and clinical findings. Based on histopathology, it has been classified into hyaline-vascular and plasmacytic forms.
The aetiology of CD is still poorly understood. Several studies have suggested a role for HHV-8 (human herpes virus) in the pathogenesis of multicentric CD (MCD). IL-6 has been implicated in the pathophysiology of Castleman's disease.
The localized forms are asymptomatic in 51% of the cases and are often discovered at the time of routine physical examination, chest x-ray or routine abdominal ultrasonography. The common sites are: thorax (63%), abdomen (12%), and axilla (4%). To date, 122 cases of retroperitoneal CD have been identified in the world literature, of which 20 % were found in the peri-renal region.[4‐7]
The clinical presentation of retroperitoneal localized CD can be due to symptoms related to compression effect on surrounding organs as nausea, vomiting, weight loss, post-prandial discomfort, abdominal or lumbar pain.
Contrast-enhanced CT scan shows dotty and stripy enhancement and rim like enhancement on the delayed scans. It can also show star-shaped microcalcifications, which are quite specific on precontrast images. Postcontrast IV study, while demonstrating dense enhancement of the mass, could demonstrate a central stellate scar. Magnetic resonance imaging (MRI) characteristics of CD are: hypodense mass on the T1 weighted study and hyperdense lesion on the T2 weighted image, sometimes with star-shaped calcifications.
The best treatment for unicentric form of CD is complete surgical excision; the prognosis of this variety being close to 100% after resection. No therapeutic consensus exists at present for the multicentric forms of Castleman's disease. Patients with multicentric disease do not benefit from surgical treatment. Complete remissions in patients have been occasionally been obtained using combination chemotherapy.