[Gastrointestinal stromal tumor of small intestine associated with lymph node metastasis: a report of 2 cases with review of literatures].
OBJECTIVE
To study the clinicopathologic features of gastrointestinal stromal tumor (GIST) of small intestine with lymph node metastasis and evaluate the respond to imatinib mesylate (Glivec) therapy.


METHODS
Two cases of GIST of small intestine associated with lymph node metastasis were collected and investigated by light microscopy and immunohistochemistry. Mutation in exon 9, 11 and of c-kit gene were analyzed by polymerase chain reaction and DNA sequencing.


RESULTS
The cases presented as small intestinal mass of irregular shape. Histologically, the tumors consisted of epithelioid and spindled cells, with areas of coagulative necrosis and hemorrhage. The mitotic count measured about 2 per 50 high-power fields. Immunohistochemical study showed that the tumor cells were diffusely distributed and strongly positive for CD117. Mutation analysis revealed that case 1 had an in-frame deletion of 11 amino-acid residues corresponding to 559-569 and carried two missense mutations involving codons 570, 571 in exon 11 of c-kit gene. Case 2 revealed an in-frame deletion involved condons 559-565 in exon 11 of c-kit gene. These two cases were all underwent primary chemotherapy with imatinib mesylate and without new tumor was found during follow-up periods (18, 26 months) after operation.


CONCLUSIONS
GIST with nodal metastasis is very rare and needs to be distinguished from other soft tissue sarcomas occurring in this site. The responsiveness to imatinib mesylate therapy correlates with the mutation status of c-kit gene.
Kong
Mei
M
Department of Pathology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310006, China.
Wang
Yan-li
YL
Xu
Lin-jie
LJ
Teng
Xiao-dong
XD
D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001549:Benzamides; D003062:Codon; D005091:Exons; D005500:Follow-Up Studies; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D006801:Humans; D000068877:Imatinib Mesylate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010879:Piperazines / Q000627:therapeutic use*; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism*; D011743:Pyrimidines / Q000627:therapeutic use*
D000970:Antineoplastic Agents; D001549:Benzamides; D003062:Codon; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit