The value of c-kit mutational analysis in a cytokeratin positive gastrointestinal stromal tumour

• Published in: Journal of clinical pathology Vol. 58; no. 9; pp. 991 - 993
• Main Authors: Rossi, G, Sartori, G, Valli, R, Bertolini, F, Bigiani, N, Schirosi, L, Cavazza, A, Luppi, G
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and Association of Clinical Pathologists 01.09.2005; BMJ; BMJ Publishing Group LTD; Copyright 2005 Journal of Clinical Pathology
• Subjects: Abdomen; Adult; Antigens; Biological and medical sciences; Biomarkers, Tumor - metabolism; c-kit; Case Reports; CD117; cytokeratin; Deoxyribonucleic acid; Diagnosis, Differential; DNA; Female; Gastroenterology. Liver. Pancreas. Abdomen; Gastrointestinal Stromal Tumors - diagnosis; Gastrointestinal Stromal Tumors - secondary; gastrointestinal stromal tumour; GIST; Hemangiosarcoma - diagnosis; Hospitals; Humans; Immunoglobulins; Investigative techniques, diagnostic techniques (general aspects); Keratins - metabolism; Medical sciences; Metastasis; Molecular weight; Morphology; Mutation; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; PCR; Pelvic Neoplasms - diagnosis; Pelvic Neoplasms - secondary; polymerase chain reaction; Proto-Oncogene Proteins c-kit - genetics; Response rates; Smooth muscle; Stomach Neoplasms - diagnosis; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; Tumors; California; Cytokeratin; Anatomic pathology; C-Onc gene; Digestive diseases; Genetics; Mutation; kit Gene; Gastrointestinal stromal tumor
• ISSN: 0021-9746; 1472-4146
• DOI: 10.1136/jcp.2004.024364

The expression of cytokeratins in gastrointestinal stromal tumours (GISTs) is rare and may lead to diagnostic confusion when it occurs. This report describes a metastatic GIST that stained strongly for cytokeratins, CD117, and CD34 in a patient who was previously diagnosed with gastric epithelioid angiosarcoma. A review of both tumours showed the same histological and immunohistochemical profiles, and c-kit molecular analysis revealed an insertional mutation at codon 558 of exon 11 in both tumours. Thus, pathologists should be aware that GISTs can occasionally express cytokeratins, and that c-kit mutational investigations may have a key diagnostic role and may prevent diagnostic mistakes that could have important clinical implications.