Uncommon morphologic patterns of lobular neoplasia

Area of Science:

• Pathology
• Oncology
• Breast Imaging

Background:

• Lobular neoplasia, encompassing atypical lobular hyperplasia and lobular carcinoma in situ, typically exhibits characteristic morphological features.
• Diagnostic challenges arise from occasional cases presenting with atypical cytologic and architectural patterns.
• These variations can mimic other benign or malignant breast lesions, complicating accurate diagnosis.

Purpose of the Study:

• To illustrate and discuss uncommon cytologic and architectural findings in lobular neoplasia.
• To highlight features that aid in distinguishing unusual lobular neoplasia from other breast pathologies.
• To reduce diagnostic errors in the interpretation of breast biopsies.

Main Methods:

• Review of histopathological slides of lobular neoplasia cases with unusual features.
• Correlation of cytologic and architectural findings with diagnostic criteria.
• Illustration of key diagnostic features for comparison.

Main Results:

• Unusual cytologic alterations such as signet-ring cells and nuclear pleomorphism were observed.
• Growth patterns in altered breast tissue (atrophy, sclerosing adenosis, etc.) led to varied appearances.
• Solid ductal involvement and "pagetoid" spread mimicked ductal carcinoma in situ and atypical ductal hyperplasia.

Conclusions:

• Unusual morphologic presentations of lobular neoplasia can cause diagnostic confusion.
• Careful evaluation of cytologic and architectural details is essential for correct diagnosis.
• Understanding these variations improves the accuracy of breast lesion interpretation.