[To improve the understanding of CD117-negative gastrointestinal stromal tumor]

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the digestive tract. The diagnosis of GIST relies mainly on clinicopathological features, tumor cell morphology and immunohistochemical marker CD117 (c-Kit). However, some tumors (about 3%-4%) have clinicopathological features of GIST but do not express CD117. To determine whether these lesions are true GIST, it is necessary to raise awareness of CD117-negative GIST. This article discusses the immunohistochemical features, gene mutations, prognosis and efficacy of targeted drugs of CD117-negative GIST. Research results suggest that CD117-negative GIST lacks KIT expression but has typical clinical, histopathological and cytogenetic features. These tumors have KIT and/or PDGFRA mutations, or are wild type. Because most KIT-negative GISTs contain PDGFRA or KIT mutation, pathologists and oncologists should not exclude GIST diagnosis based on negative immunohistochemical staining of KIT. It is known that approximately 30% of PDGFRA mutations may be sensitive to imatinib, and patients with such tumors may benefit from imatinib, so imatinib treatment should not be empirically denied in these patients.

Surgical method choice and coincidence rate of pathological diagnoses in transduodenal ampullectomy: A retrospective case series study and review of the literature

BACKGROUND

Transduodenal ampullectomy (TDA) is not in wide clinical use due to its low radical effect and a high recurrence rate of tumors. However, TDA is still an effective treatment method; it has great clinical value in cases of duodenal benign tumors, precancerous lesions, and benign and malignant borderline tumors, and can avoid the risks associated with pancreaticoduodenectomy with larger resection range and greater thoroughness than endoscopic papillectomy.

AIM

To investigate the surgical method choice and the coincidence rate of pathological diagnoses in TDA for ampullary neoplasms.

METHODS

Ten patients with ampullary neoplasms underwent TDA based on the fact that their endoscopic biopsy results suggested benign lesions, and the endoscopic ultrasound (EUS)-assessed tumors were resectable. All cases underwent duodenal ampullary lesion endoscopic biopsy, intraoperative frozen-section pathological examination, and postoperative pathological examination.

RESULTS

This study included seven patients with benign tumors and three with malignant tumors (1 pTis, 2 pT1), according to the postoperative pathology results. The coincidence rate of the postoperative pathology results with the intraoperative frozen-section biopsy results was 100% (10/10), and the coincidence rate with the endoscopic biopsy results was 70% (7/10) based on pathological characteristics. The endoscopic biopsy false-negative rate was 30% (3/10). All patients were followed for 6 to 70 mo without tumor recurrence or metastasis.

CONCLUSION

The coincidence rate of postoperative pathology results, intraoperative frozen-section pathology results, and endoscopic biopsy results is the restraining factor of TDA clinical application. Endoscopic biopsy results and EUS have importance relevance to surgical planning. Intraoperative frozen-section pathology results have a significant influence on the choice of surgical procedure.

Infantile hepatic hemangioendothelioma: A clinicopathologic study in a Chinese population

AIM: To investigate whether the clinicopathologic features of infantile hemangioendothelioma (IHE) of the liver in a Chinese population are similar to the features observed in other races.

METHODS: The clinical data, radiological findings, histopathological changes and outcome of 12 cases of IHE diagnosed by the Department of Pathology, West China Hospital over the last 10 years were analyzed retrospectively. Immunohistochemical studies were carried out using antibodies against CD31, CD34, Factor VIII, cytokeratin 8 and cytokeratin 18.

RESULTS: The 12 patients were aged from fetal to 5 years (three males and nine females). The tumor was presented with different clinical manifestations, mainly as an asymptomatic, palpable, upper abdominal mass, except for the two fetuses who were detected antenatally by ultrasound. In one patient, this presentation was accompanied by an initial severe pneumothorax. No symptoms of congestive heart failure were present and neither congenital abnormalities nor vascular tumors in the skin or other organs were found. Laboratory abnormalities included leukocytosis (40%), anemia (60%), thrombocytosis (60%), hyperbilirubinemia (16.7%), abnormal liver function (50%) and increased α-fetoprotein (80%). Based on radiological findings and gross specimens, the tumor presented as a solitary lesion or a multifocal space-occupying lesion. The tumor size ranged from 5.0 cm × 3.5 cm × 2.0 cm to 13.8 cm × 9.0 cm × 7.7 cm, and the 0.2-1.1 cm nodules were diffusely distributed within the multifocal tumor. Seven cases were surgically resected, three cases underwent biopsy and the two fetuses were aborted. Histologically, nine cases were classified as type I and three as type II, presenting aggressive morphologic features, immature vessels, active mitosis and necrosis. An inflammatory component, predominantly eosinophilic granulocytes, sometimes obscured the nature of the tumor. Ten patients are alive after a follow-up of 1-9 years. Based on immunohistochemistry, the endothelial cells in all cases were positive for CD31, CD34 and polyclonal factor VIII antigen, whereas the scattered hyperplasia bile ducts were positive for cytokeratin 8 and cytokeratin 18.

CONCLUSION: The clinical manifestations of IHE are non-specific. There is no significant correlation between histological type and prognosis. The clinicopathologic features of IHE in Chinese patients may provide a clue to further evidence-based studies.