Issues

Pleural fluid cytology specimen from a 45-year-old female never smoker with a lung mass showing malignant cells forming three dimensional flower-like arrangements, consistent with adenocarcinoma. The patient also had a biopsy of a spinal metastasis that showed squamous cell carcinoma. Both the pleural fluid and spine metastasis specimens harbored the same EGFR mutation, supporting their derivation from a single adenosquamous carcinoma of the lung. This patient illustrates how the discovery of an EGFR mutation in a small biopsy diagnosed as squamous carcinoma should raise suspicion for an underlying adenosquamous carcinoma. For details, see the article by Rekhtman and colleagues on page 1167 of this issue.