RESUMEN
Matrix-producing carcinoma (MPC) of the breast is an extremely rare variant of metaplastic breast carcinoma that contains a mixture of epithelial and mesenchymal elements. As overt carcinoma with direct transition to a cartilaginous and/or osseous stromal matrix cells, MPC is of no spindle cells between those two elements. This is the case of a 43 year-old female patient with MPC which coexisted with microglandular adenosis (MGA), atypical MGA (AMGA) and carcinoma in situ arising in MGA (MGACA in situ). MGA is a rare, infiltrative, benign lesion of the breast with an indolent clinical course. Histological evidence of carcinoma arising from MGA has previously been documented. MPC arising in MGA is an extremely rare subtype of breast carcinoma and has been seldom detailed described in the previous studies. This report highlights one such case with cytomorphological and histopathological correlation, along with a review of pertinent literature and differential diagnosis.