Peripheral squamous cell carcinoma of the lung: Potential pitfalls in biopsy interpretation

ABSTRACT: Most of the patients with lung cancer present with inoperable advanced stage disease. Therapeutic decisions are therefore often made of the basis of diagnoses rendered from small biopsy and cytological samples. The quantitative and qualitative limitations of these samples often result in difficulties subclassifying carcinomas, especially the poorly differentiated non-small cell lung carcinomas. Thus, immunohistochemical studies, not without their own limitations, are often used. We present a case of a peripheral poorly differentiated squamous cell carcinoma of the lung with interstitial and lepidic growth patterns that yielded disparate findings in the preoperative biopsy and cytology cellblock materials and discuss potential pitfalls in the diagnosis of this malignancy.