We report the case of a 13-yr-old patient with retarded growth and a 2-yr background of asthenia, anorexia, and fever, whose laboratory data revealed anemia, thrombocytosis, an elevated erythrocyte sedimentation rate, ferropenia, hyperglobulinemia, hyperfibrinogenemia, and presence of a lupus-like circulating anticoagulant. Clinical studies revealed a tumor-like overgrowth in the gastric wall, and surgery confirmed its subserosal localization in the gastric fundus. After total removal of the mass, the systemic manifestations disappeared. The pathological study revealed the existence of the hyaline-vascular variety of Castleman's disease. Having reviewed the medical literature, we have not found a single unquestionable case of gastric Castleman's disease, although three other cases have been described as gastric pseudolymphoma which, when analyzed, could correspond to typical cases of Castleman's disease. Likewise, this is the second case associated with a circulating anticoagulant of lupoid characteristics. We conclude that Castleman's disease should be included in the differential diagnosis of gastric lesions of lymphoid nature and in the series of processes associated with lupus anticoagulant.