Solid Lung Adenocarcinoma

**Semantic type:** Neoplastic Process

**Definition:** A morphologic variant of lung adenocarcinoma characterized by the presence of polygonal malignant cells forming sheets. Acinar, papillary, micropapillary, or lepidic growth patterns are absent. If the tumor is 100 percent solid, intracellular mucin should be present in at least five tumor cells in each of two high-power fields and confirmed with mucin immunohistochemical stains. Tumors formerly classified as large cell carcinomas expressing pneumocyte immunohistochemical markers, even if intracellular mucin is absent, are now included in this category.

**Synonyms:** - Lung Solid Adenocarcinoma with Mucin - Pulmonary Solid Adenocarcinoma with Mucin - Solid Adenocarcinoma of Lung with Mucin - Solid Adenocarcinoma of the Lung with Mucin - Solid adenocarcinoma