Double primary malignancies associated with colon cancer in patients with situs inversus totalis: two case reports.

Situs inversus totalis (SIT) is not itself a premalignant condition, however, rare synchronous or metachronous multiple primary malignancies have been reported. Herein we present a case of synchronous transverse and sigmoid colon cancers and a case of metachronous rectosigmoid colon and gastric cancers in patients with SIT.A 66-year-old male with SIT was referred for a two-month history of hematochezia. Synchronous colonic tumors were found on the proximal transverse and sigmoid colon. The patient underwent open total colectomy and was discharged without incident. A 71-year-old female with rectosigmoid colon cancer and SIT underwent laparoscopy-assisted low anterior resection. Fourteen months after the surgery, the patient developed a single hepatic metastasis and underwent hepatic segmentectomy (S6). Forty-six months after laparoscopy-assisted low anterior resection, the patient developed metachronous early gastric cancer on the antrum and underwent radical subtotal gastrectomy with gastroduodenostomy. The patient is doing well without recurrence for 28 months.