title: Primary pulmonary adenocarcinoma with intestinal differentiation mimicking metastatic colorectal carcinoma: case report and review of literature.
abstract: Pulmonary adenocarcinoma with intestinal differentiation is rare and typically expresses proteins common to lung primaries. We report a case in a 51-year-old woman with a solitary 3.3-cm mass in the left lower lobe. Additional clinical investigation, including positron emission tomography scan with fluorine 18-labeled fluorodeoxyglucose, colonoscopy, and capsule endoscopy of her small bowel, revealed no evidence of tumor elsewhere. She underwent left lower lobectomy with mediastinal lymphadenectomy. Histologic examination revealed tall columnar cells without goblet cell differentiation arranged in a cribriform and acinar pattern with extensive central necrosis. Metastatic carcinoma was present in multiple hilar lymph nodes. Mediastinal lymph nodes were negative. Immunohistochemical stains demonstrated diffuse positivity for cytokeratin (CK) 20 and CDX-2 in neoplastic cells with negative staining for CK7 and thyroid transcription factor-1. CK7 expression has been documented in all 14 cases previously reported. This is the first description of pulmonary adenocarcinoma with intestinal differentiation with histopathologic and immunophenotypic findings indistinguishable from metastatic colorectal adenocarcinoma.
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Hong C
authors.initials: HC
authors.lastname: Li
authors.forename: Lindsay
authors.initials: L
authors.lastname: Schmidt
authors.forename: Joel K
authors.initials: JK
authors.lastname: Greenson
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Chang
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Myers
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000473:pathology*; D000071616:CDX2 Transcription Factor; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000556:secondary*; D005260:Female; D018398:Homeodomain Proteins / Q000032:analysis; D006801:Humans; D053554:Keratin-20 / Q000032:analysis; D008175:Lung Neoplasms / Q000175:diagnosis / Q000473:pathology*; D008875:Middle Aged; D049268:Positron-Emission Tomography; D015534:Trans-Activators / Q000032:analysis
chemical_list: D000071616:CDX2 Transcription Factor; D018398:Homeodomain Proteins; D053554:Keratin-20; D015534:Trans-Activators