E2504. Histologic and Radiologic Spectrum of Columnar Cell Lesions to In Situ Carcinoma
  1. Rasha Ismail; Yale New Haven Health/Bridgeport Hospital
  2. Hagar Mahmoud; Yale New Haven Health/Bridgeport Hospital
  3. Aishwariya Vegunta; Yale New Haven Health/Bridgeport Hospital
  4. Paul Cohen; Yale New Haven Health/Bridgeport Hospital; Yale School of Medicine
  5. Kiran Sheikh; Yale New Haven Health/Bridgeport Hospital; Yale School of Medicine
Columnar cell lesions (CCLs) of the breast are more often diagnosed in biopsies performed for abnormal calcifications seen on mammography. CCLs are characterized by dilation of the terminal duct lobular units (TDLU) and substitution of cuboid epithelial cells to tightly packed columnar epithelial cells. Columnar cell alteration can be divided into three main histologic categories: 1) single columnar cell layer including columnar cell change without atypia (CCC) and flat epithelial atypia (FEA), 2) cell stratification with multiple layers including columnar cell hyperplasia without atypia (CCH) and FEA, and 3) complex architecture with atypia including atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS). Among CCLs, FEA is considered a high-risk lesion with a variable upgrade rate to malignancy ranging from 2 - 7%. ADH and low-grade DCIS are distinguished from FEA by the presence of complex architectural patterns such as well-developed micropapillae and rigid cellular bridges. Radiologic morphology of CCLs is often grouped by amorphous or fine pleomorphic calcifications that develop within multiple terminal duct lobular units from secretion of calcium deposits inside the lumen by the epithelial cell lining. Over time, these calcium deposits show laminar concentric appearance and give rise to histological psammomatous calcifications, which can be typical for both benign and malignant lesions. The Magnetic resonance imaging (MRI) appearance on of CCLs is even more nonspecific. The importance of histologic and radiologic appearance of CCLs is due to its progressive spectrum and coexistence with atypical lesions, which ultimately determines its management.

Educational Goals / Teaching Points
Review of algorithmic approach to histologic diagnosis of columnar cell lesions. Illustrate mammographic and Magnetic resonance imaging (MRI) features of columnar cell lesions to in situ carcinoma. Discuss the clinical significance and management of columnar cell lesions.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
This exhibits provides a pictorial review of biopsy-proven columnar cell lesions (CCL), flat epithelial atypia (FEA), atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS) including morphology on mammogram and/or MRI with pathological correlation.

CCLs in the breast encompass a spectrum of histologic changes, ranging from simple CCC to more complex CCH with and without atypia to in situ carcinoma (DCIS). Familiarity with the radiologic and pathologic spectrum of CCLs is essential for a multidisciplinary approach to management.