Objective:

To investigate the radiographic and clinicopathologic characteristics of matrix-producing carcinoma (MPC) of the breast.

Methods:

A total of 12 cases diagnosed as MPC of the b

reast were retrospectively analyzed for radiographic and clinicopathologic findings

immunophenotypes

treatment and prognosis

followed with review of the literatures.

Results:

The patients were all female

mean age 50 years (range 43-74 years). A relative well-circumscribed hypoechoic nodular lesion with posterior echo pattern was revealed by ultrasonography

with Breast Imaging Reporting and Data System (BI-RADS) categories 3-4A. MRI revealed a low-intensity tumor with T1 imaging and a high-intensity tumor with T2 imaging

with BI-RADS categories 4C-5. All patients were single mass. The size of tumors was 1.5-9.0 cm. Macroscopically

the tumor showed relatively well-circumscribed pale nodular lesion

with mucilaginous edge in some area. On microscopic evaluation

all the invasive components showed an abrupt transition to chondromyxoid matrix without an intervening spindle cell sarcomatoid component. The overt invasive carcinoma components were all invasive ductal carcinoma. On immnuohistochemical evaluation

11 cases were triple-negative breast cancer (TNBC). Ten cases were positive for cytokeratin 5/6 (CK5/6) and epidermal growth factor receptor (EGFR). All cases were positive for S-100 protein. Follow-up information of all cases were obtained. Follow-up time ranged 8-30 months. At the time of initial diagnosis

3 patients had axillary lymph node metastasis. All patients were surviving. Nine patients were surviving with diseasefree

one patient had lung metastasis 16 months after surgery

one patient had lung metastasis 8 months after surgery

and one patient had recurrence in thoracic wall 11 months after surgery.

Conclusion:

MPC of the breast is an extremely rare variant carcinoma of the breast

and its ultrasonographic features were similar to many lesions or tumors

always leading to missed diagnosis. MRI had relatively higher sensitivity in the diagnosis of MPC of the breast. Thorough understanding of the pathological features of this disease and usage of immunochemical

panel could make the patients benefit from the subsequent treatment.