Non-epithelial tumors of the gastrointestinal tracts are very rare. Its incidence is about 1-5% of the all neoplasmas of the gastrointestinal tract. Benign non-epithelial tumors in the small intestine are occupied about 60% of all benign tumors. But there is very low frequency in the stomach, colon and rectum. The incidence of the malignant non-epithelial tumors (sarcoma) is very rare, 1-2% of all malignant tumors in stomach and large intestine. However, in the small intestine, it is showed to be over 40% in sarcoma. Of all benign non-epithelial tumors, histologically leiomyoma and benign lipoma are very common. Most of sarcoma are malignant lymphoma and leiomyosarcoma, and other tumors are very rare.It is very important to differentiate leiomyosarcoma from neurogenic sarcoma. Almost cases which were previously reported as neurogenic tumor, especially neurinoma or neurogenic sarcoma of the gastrointestinal tract, are probably leiomyosarcoma and leiomyoma. In this paper we emphasized the importance of histological differential diagnosis between leiomyosa-rcoma and neurogenic tumors in the gastrointestinal tract. And we reported a case of solitary neurogenic sarcoma of the small intestine.Recently, lymphoid-plasmacytic disorders associated with appearance of a unique serum and urinary protein, which is Fc-fragment of the counterpart of the heavy chain of Ig-G, are known as heavy chain disease. We have experienced a case of heavy chain disease, which was involved the gastrointestinal tract. We cannot find any reports of heavy chain disease involving the gastrointestinal tract. Histologically heavy chain disease features (reticulum cell sarcoma like and Hodgkin desease like) but malignant lymphoma, and remarkable plasma cell infiltration was noted. This feature is very characteristic of this disease. Ig-A heavy chain disease (α-chain disease) arises from small intestine. The characteristical histoligical findings is diffuse plasma cell infiltration and clinically associated with malabsorption.