Gastrointestinal stromal tumour (GIST) is a common mesenchymal tumour arising in the gastrointestinal tract, but not frequently encountered in the rectum. Herein, we describe a case of a rectal GIST which mimicked histomorphological features of a schwannoma; thus, making intraoperative frozen section evaluation challenging. Although subsequent immunohistochemistry and molecular findings readily confirmed the diagnosis of a GIST, we wish to draw attention to three clues that will help the pathologist steer clear of this potential diagnostic pitfall. One, GISTs are relatively more common than schwannomas in the rectum. Two, schwannomas usually have very little mitoses. Three, rectal GISTs commonly exhibit nuclear palisades. We also discuss the diagnostic, prognostic and therapeutic functions of immunohistochemical and molecular investigations. As the surgical intent for rectal GISTs is for en-bloc excision with wide margins, we surmise that the intraoperative consult should include GIST as a possible differential diagnosis for rectal mesenchymal tumours. In view of the potential for neoadjuvant treatment with imatinib before surgical excision to preserve sphincter function, a multidisciplinary approach is recommended for establishing most effective treatment strategy in these rare complex cases.
During 10-19 March 1999, 11 workers in 1 of 2 Singaporean abattoirs developed Nipah-virus associated encephalitis or pneumonia, resulting in 1 fatality. A case-control study was conducted to determine occupational risk factors for infection. Case patients were abattoir A workers who had anti-Nipah IgM antibodies; control subjects were randomly selected abattoir A workers who tested negative for anti-Nipah IgM. All 13 case patients versus 26 (63%) of 41 control subjects reported contact with live pigs (P=.01). Swine importation from Malaysian states concurrently experiencing a Nipah virus outbreak was banned on 3 March 1999; on 19 March 1999, importation of Malaysian pigs was banned, and abattoirs were closed. No unusual illnesses among pigs processed during February-March were reported. Contact with live pigs appeared to be the most important risk factor for human Nipah virus infection. Direct contact with live, potentially infected pigs should be minimized to prevent transmission of this potentially fatal zoonosis to humans.