Anorectal melanoma with a KIT-activating mutation, which is a target for tyrosine kinase inhibitor.
Recent advances in our understanding of the genetic mutations associated with melanoma have led to the classification of distinct melanoma subtypes. A number of reports have consistently demonstrated that mucosal and acral melanomas more commonly harbor KIT-activating mutations than do other subtypes. Success in treating gastrointestinal stromal tumors with imatinib has led to speculation that KIT-mutated melanoma might also be effectively managed using this approach. A 78-year-old woman presented with a 4-month history of rectal bleeding. A colonoscopy revealed a black polypoid mass, 30 mm in diameter, originating near the dentate line, and a biopsy revealed malignant melanoma. Computed tomography showed multiple liver and lung metastases. A KIT mutation analysis showed the L576P mutation in exon 11. The patient did not want to undergo chemotherapy including a tyrosine-kinase inhibitor, so palliative radiotherapy for rectal symptoms was performed, but the patient died 4 months later due to disease progression. We describe the first case of anorectal melanoma with a KIT-activating mutation in Japan and summarize findings from the literature regarding the efficacy of KIT kinase inhibitors on this melanoma subtype.
Department of Gastroenterology, Kushiro City General Hospital, 1-12, Shunkodai, Kushiro, 085-0822, Japan.
Miki
M
Itoh
Akira
A
Goto
Hideki
H
Wakasugi
Yutaka
Y
Yoshida
Yasutaka
Y
Matsunaga
Kenichi
K
Fujii
Kazuya
K
Suzuki
Kazuhiko
K
Yonezawa
Takashi
T
Abe
Yoshiaki
Y
Arimura
Yasuhisa
Y
Shinomura
D000368:Aged; D001005:Anus Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000532:radiotherapy; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary; D008175:Lung Neoplasms / Q000556:secondary; D008545:Melanoma / Q000235:genetics* / Q000473:pathology* / Q000532:radiotherapy; D010166:Palliative Care; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D019009:Proto-Oncogene Proteins c-kit / Q000037:antagonists & inhibitors / Q000235:genetics*; D012004:Rectal Neoplasms / Q000235:genetics* / Q000473:pathology* / Q000532:radiotherapy
D047428:Protein Kinase Inhibitors; D019009:Proto-Oncogene Proteins c-kit