Abstract
We describe the case of a 56-year-old woman who was detected to have elevation of the serum CEA level during annual postoperative monitoring for tumor marker levels after treatment for ovarian cancer. Screening FDG-PET revealed focal FDG uptake in the upper quadrants of the right breast. The patient was found to have no palpable breast mass, and mammography showed no abnormal findings ; however, breast ultrasound (US) revealed diffuse ill-defined patchy hypoechoic lesions in the upper quadrants of the right breast. US-guided core needle biopsy revealed the diagnosis of ductal carcinoma in situ (DCIS). A subsequent MRI examination of the breast revealed an extensive enhancing region in the right upper breast. Modified radical mastectomy with axillary sentinel node biopsy was performed. Histopathological examination of the resected surgical specimen revealed extensive intraductal proliferation of tumor cells that mostly showed a solid growth pattern in a fibrovascular papillary stroma. Neuroendocrine differentiation was confirmed by immunohistochemistry for chromogranin A, and neuron-specific enolase. In addition, the tumor cells were strongly positive for CEA. The serum CEA level decreased rapidly to the normal range within one month after the surgery. This is an extremely rare case, in which CEA produced by the tumor cells of DCIS of the breast caused elevation of the serum CEA.
