Primary small bowel carcinoid tumor with bilateral breast metastases: report of 2 cases with different clinical presentations.
BACKGROUND
Carcinoid tumor metastatic to the breast is uncommon and can closely mimic a mammary carcinoma. The differentiation of metastatic carcinoid tumor from primary breast tumor is important, however, owing to different clinical management and prognosis.


OBJECTIVE
The purpose of this study was to describe 2 patients with bilateral metastatic carcinoid tumors to the breast with different clinical manifestations.


METHODS
We examined the radiological, clinical, cytologic, histologic, immunohistochemical, and ultrastructural features of these 2 cases.


RESULTS
In case 1, the tumor presented initially as a stellate mass on mammogram and was diagnosed as grade II infiltrating ductal carcinoma. It was only after the discovery of small intestinal, liver, ovarian, and contralateral breast masses, as well as careful morphologic and immunohistochemical evaluations, that the true nature of the tumor was realized. In case 2, the tumor initially presented as a small intestinal tumor with liver metastases and bilateral breast masses. The breast masses were diagnosed accurately as metastatic carcinoid tumor by morphologic and immunohistochemical evaluations.


CONCLUSIONS
Metastatic carcinoid tumor to the breast is uncommon, but poses a diagnostic challenge in that morphologically it can closely mimic a primary breast tumor. Careful attention to clinical features and the use of auxiliary immunohistochemical studies can help in arriving at the correct diagnosis.
Department of Pathology and Laboratory Medicine, Emory University, Grady Memorial Hospital, Atlanta, Ga, USA.
Marina B
MB
Mosunjac
Ruby
R
Kochhar
Mario I
MI
Mosunjac
Stephen K
SK
Lau
D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D002276:Carcinoid Tumor / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007414:Intestinal Neoplasms / Q000473:pathology*; D007421:Intestine, Small; D008875:Middle Aged