Sections reveal a well-circumscribed, well-differentiated adenocarcinoma with unusual histology. The adenocarcinoma is composed of tubular and cribriform glands with a vague papillary appearance. The glands are comprised of tall columnar cells with nuclear stratification, clear to light eosinophilic cytoplasm, supra and subnuclear vacuolization, little nuclear pleomorphism, and inconspicuous nucleoli. The stroma consists of scant, mature spindle cells with little desmoplasia. PAS and diastase predigested PAS reveal an abundant amount of glycogen within the cytoplasm of the cells. Mucicarmine and diastase predigested PAS stains show intraluminal mucin, however, a significant amount of mucin is not identified within the cytoplasm of the columnar cells. Visceral pleural and angiolymphatic invasion are noted.