Section show a good-size needle core biopsy of liver parenchyma containing a deposit of malignant tumor. The tumor comprises large epithelioid cells arranged in solid nests. The cells have moderately to markedly pleomorphic nuclei, small nucleoli, and abundant basophilic cytoplasm.  No clear cut features of specific differentiation are identified in the H&E sections (no definite gland formation, mucin production, or keratinization). The tumor is partly necrotic. The peritumoral liver parenchyma shows non-specific changes consistent with proximity to a mass lesion, as well as mild macrovesicular steatosis.

The lesion is most likely metastatic non-small cell carcinoma. Immunohistochemical stains underway to further assess the differentiation of the lesion and possible primary sites of origin.   

Diagnosis

Liver biopsy - large cell malignant neoplasm, most likely representing metastatic poorly differentiated non-small cell carcinoma.