A Long-surviving Case of Metastatic Extragastrointestinal Stromal Tumor arising from Greater Omentum by Surgical Treatment

Tomohiko Setoguchi, Yoshito Ikematsu¹⁾, Yuki Nakata¹⁾, Toshikazu Kanai¹⁾, Yoshiro Nishiwaki¹⁾, Hideo Kida¹⁾, Hiroki Mori²⁾, Takachika Ozawa³⁾, Manabu Ohta and Hiroyuki Konno

Second Department of Surgery, Hamamatsu University School of Medicine
Department of Surgery, Hamamatsu Medical Center¹⁾
Department of Pathology, Hamamatsu University School of Medicine²⁾
Department of Pathology, Hamamatsu Medical Center³⁾

A 63-year-old man seen for upper abdominal pain was found in abdominal ultrasonography (US) to have confirmed in a huge hepatic tumor. Computed tomography (CT) and abdominal angiography to be a hypervascular solid tumor, necessitating right trisegmentectomy of the liver, based upon a diagnosis of liver metastasis from an omental tumor resected and diagnosed 15 years earlier as leiomyosarcoma. Histological examination showed spindle cells forming a fascicular pattern. Immunohistochemical analysis showed the tumor to be positive for KIT but negative for myogenic or neurogenic makers. The omental tumor resected previously had shown exactly the same staining patterns in all markers tested, indicating that the liver tumor had metastasized from the extragastrointestinal stromal tumor (EGIST) arising from the omentum. A tumor recurred at the base of the skull 6.5 years after the hepatectomy, after which the patient was administered sunitinib after tumorectomy. No evidence exists on EGIST treatment or prognosis, and the biological difference between EGIST and ordinary GIST remains unclear. The clinicopathological features must therefore be determined to clarify a strategy for metastatic EGIST.

Key words
EGIST, liver metastasis, brain metastasis

Reprint requests
Tomohiko Setoguchi Second Department of Surgery, Hamamatsu University School of Medicine
1-20-1 Handayama, Higashi-ku, Hamamatsu, 431-3192 JAPAN

Accepted
January 27, 2010

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