Synchronous double tumor of breast cancer and gastrointestinal stromal tumor in a patient with neurofibromatosis type 1: report of a case.

We report a rare case of synchronous double tumor formation of breast cancer and gastrointestinal stromal tumor (GIST) in a patient with neurofibromatosis type 1(NF-1). A 76-year-old woman with a history of NF-1 who had undergone left modified mastectomy for breast cancer seven years previously was admitted to our hospital because of a right breast tumor and abdominal discomfort. Computed tomography revealed an enhanced irregular tumor in the right breast and peripheral enhanced tumors in the abdomen. The patient underwent right modified mastectomy and laparoscopic tumor resection combined with small intestine surgery. Histopathological examination revealed the presence of invasive lobular carcinoma in the right breast and GIST in the abdomen. The synchronous development of breast cancer and GIST in a patient with NF-1 is extremely rare, with this being the second case ever reported.