Pseudoinvasion in intraductal carcinoma

Area of Science:

• Oncology
• Pathology
• Surgical Pathology

Background:

• Pre-excision procedures such as fine-needle aspiration, stereotactic biopsies, and guide wire localization can cause trauma to mammary lesions.
• This trauma may lead to the dislodgement of tumor cells, creating diagnostic challenges and potential misinterpretation of tissue artifacts as invasive carcinoma.

Purpose of the Study:

• To investigate the phenomenon of tumor cell dislodgement following breast biopsy procedures.
• To analyze the impact of needle aspiration and needle localization on the histological appearance of intraductal carcinoma.

Main Methods:

• Review of eight breast biopsy specimens diagnosed with intraductal carcinoma.
• Histopathological examination to identify dislodged tumor cell clusters in the stroma or adipose tissue.
• Correlation of findings with prior biopsy methods, including needle aspiration and needle localization.

Main Results:

• In all eight cases, dislodged tumor cell clusters were identified in the stroma adjacent to disrupted ducts containing intraductal carcinoma.
• Cases with prior needle aspiration showed significant hemorrhage and reactive changes with small tumor cell clusters in blood pools.
• Needle localization specimens exhibited minimal tissue reaction with larger detached cell clusters.

Conclusions:

• Breast biopsy procedures involving needles or guide wires can disrupt mammary ducts with intraductal carcinoma.
• Dislodged tumor cells can simulate invasive carcinoma, leading to diagnostic difficulties.
• Limiting the number of needle passes is recommended to preserve the architectural integrity of the lesion and minimize iatrogenic changes.