Authors: Rudainy Kaddoura , Salim Al Rahbi , Zakiya Al Ajmi , Hiba Al Mahruqi

Abstract

Background: Pleomorphic carcinoma of the breast is a rare and aggressive histologic variant of invasive breast carcinoma characterized by the presence of highly atypical, bizarre, pleomorphic giant cells. It typically portends a poor prognosis and poses diagnostic challenges due to its undifferentiated morphology.

Case Presentation: We report the case of a 39-year-old woman who presented with a 5-month history of a progressively enlarging left breast mass. Imaging revealed a large, irregular lesion without overt metastatic disease. Histopathology demonstrated a high-grade pleomorphic undifferentiated epithelioid neoplasm, with triple-negative receptors expression. Immunohistochemistry suggested an undifferentiated epithelioid neoplasm requiring exclusion of metastasis. Modified radical mastectomy was performed, and PET <AQ1>-CT excluded other primary sources, confirming this as a primary breast malignancy.

Conclusion: Primary undifferentiated pleomorphic carcinoma of the breast is rare and diagnostically challenging. Multimodal imaging, expert histopathological analysis, and exclusion of metastasis are essential for diagnosis and management. This case underscores the need for clinical suspicion in atypical high-grade breast tumors

Keywords: Breast, Cancer, Undifferentiated, Pleomorphic, carcinoma