Cluster of Differentiation 10 Positive Stromal Sarcoma of Breast: A Diagnostic Challenge

Stromal sarcomas of the breast are a group of rare and heterogeneous tumors which mimic malignant phylloides tumor and metaplastic carcinoma histologically. These tumors have been reported in the literature mostly in form of small retrospective case series and case reports, making it difficult to characterize their exact histopathological spectrum and management strategy. Our patient was a 65-year-old female who presented with a 3-month history of a lump in the left breast. Examination revealed an immobile mass in upper and outer quadrant of left breast, 5 x 4 cm in diameter. Trucut biopsy revealed sheets of atypical spindle cells. She underwent a modified radical mastectomy. On histopathology, we found malignant mesenchymal tumor positive for vimentin and cluster of differentiation 10 (CD10). Thus, a rare diagnosis of CD10 positive mammary stromal sarcoma was established. The case has been reported for its rarity and to highlight the importance of a meticulous histopathological examination for excluding close differentials.