Localized plasma cell type Castleman's disease (CD) is an unusual pathologic entity. It is frequently associated with clinical and laboratory characteristics and rarely occurs in children. Total surgical excision results in cure in all aspects. To make early diagnosis of mesenteric CD is not easy, especially for children. An 11-year-old Taiwanese boy was recently evaluated for anemia and delayed growth. His clinical findings included a syndrome of severe hypochromic microcytic anemia, neutropenia, thrombocytosis, hypoferremia, hypergammaglobulinemia, and growth failure. Radiological examinations (abdominal ultrasound, small intestinal series, and computerized tomography) identified hepatosplenomegaly, nephromegaly, and huge masses in the middle abdomen with precaval, celiac, and paraaortic lymph nodal enlargement. However, detailed physical examination failed to detect a mass. At laparotomy a double-fist-sized confluent mass was found arising from the mesenteric root. Most masses were discrete and were excised individually. The pathologic diagnosis was plasma-cell type angiofollicular lymph node hyperplasia (Castleman's disease). Seven weeks after surgery, he had an episode of acute hepatitis B. Postoperatively, he exhibited a dramatic growth spurt; the hemoglobin, red blood cell indices, serum iron, and immunoglobulins returned to normal in 2 months. Neutropenia, which has not been previously related to mesenteric CD, was an unexpected finding in our case; however, it resolved spontaneously 3 months after the surgery, suggesting its causal relationship with the tumor.