Gastrointestinal stromal tumors in Japanese patients with neurofibromatosis type I.
BACKGROUND
Neurofibromatosis type I (NF1) predisposes patients to various neoplasias, including gastrointestinal stromal tumors (GISTs). Little is known about the risk of developing GISTs for NF1 patients or the clinicopathologic features and prognosis of NF1-GIST.


METHODS
We conducted a multi-detector computed tomography screen for adult NF1 patients between 2003 and 2012. Clinicopathologic data of sporadic GISTs from patients who underwent surgery between 2001 and 2010 were retrospectively collected from 32 hospitals in Japan.


RESULTS
CT screening identified 6 GIST patients from the 95 NF1 patients screened, suggesting that the prevalence rate of GISTs was approximately 6.3/100 in NF1 patients. All 6 NF1 patients exhibited hyperplasia of the interstitial cells of Cajal in the adjoining small intestine. NF1-GISTs may account for 1.1-1.3 % of primary sporadic GISTs and present as multiple tumors in the small intestine, with low mitotic activity and no KIT or PDGFRA mutations. The risk of recurrence and mortality is very similar between NF1 and non-NF1 patients after surgical resection of GISTs.


CONCLUSIONS
NF1 patients may be predisposed to developing small intestinal GISTs, which may appear as multiple GISTs without KIT and PDGFRA mutations. The prognosis of patients with NF1-GISTs is similar to patients with conventional GISTs.
Department of Surgery, Osaka Police Hospital, Osaka, Japan. tnishida@east.ncc.go.jp.|Department of Surgery, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba, 277-8577, Japan. tnishida@east.ncc.go.jp.
Toshirou
T
Nishida
Department of Pathology, Osaka Police Hospital, Osaka, Japan.
Masahiko
M
Tsujimoto
Department of Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
Tsuyoshi
T
Takahashi
Department of Surgical Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
Seiichi
S
Hirota
Centre Leon Bernard of the Université Claude Bernard, Lyon, France.
Jean-Yves
JY
Blay
Department of Dermatology, Osaka University Graduate School of Medicine, Osaka, Japan.
Mari
M
Wataya-Kaneda
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D046152:Gastrointestinal Stromal Tumors / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D009456:Neurofibromatosis 1 / Q000150:complications* / Q000000981:diagnostic imaging; D015995:Prevalence; D012189:Retrospective Studies; D055815:Young Adult
Clinicopathologic features; Gastrointestinal stromal tumor; Neurofibromatosis type I; Prognosis