title: Basaloid adenocarcinoma. A new variant of pulmonary adenocarcinoma.
abstract: The 2004 WHO classification of lung tumours recognised basaloid carcinoma as a variant of squamous and large cell carcinoma. We report a unique case of primary pulmonary adenocarcinoma with a basaloid component. An 82-year-old man underwent pulmonary lobectomy for a 2.8 cm tumour. The patient is disease-free 13 months after diagnosis. Histologically, an invasive carcinoma having a glandular and a solid component was observed. The former was an adenocarcinoma with mucus containing spaces lined by columnar mucinous cells and basaloid cells. The solid component was an organoid proliferation of basaloid-type cells, as in cutaneous basal cell carcinoma. Basaloid cells, but not mucinous cells, were immunoreactive for high molecular weight cytokeratins (CK), CK 7 and, focally, for TTF-1. High Ki67 index, p53 and EGFR expression were also found. This tumour is unique in several respects: (1) The solid areas resemble a conventional basaloid carcinoma, except for the presence of small mucin-containing spaces. (2) The mucinous adenocarcinoma areas contain two layers of columnar and basaloid cells. (3) Both components are neoplastic based on cell morphology, invasive properties and phenotypic profile. These findings indicate that a basaloid variant of adenocarcinoma is also existing in the spectrum of basaloid carcinomas of the lung.
authors.affiliation: Department of Pathology, University of Turin at San Luigi Hospital, Orbassano, Turin, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Marci
authors.forename: Marco
authors.initials: M
authors.lastname: Volante
authors.forename: Susanna
authors.initials: S
authors.lastname: Cappia
authors.forename: Luisella
authors.initials: L
authors.lastname: Righi
authors.forename: Corrado
authors.initials: C
authors.lastname: Novello
authors.forename: Giorgio V
authors.initials: GV
authors.lastname: Scagliotti
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Brambilla
authors.forename: Mauro
authors.initials: M
authors.lastname: Papotti
mesh_terms: D000230:Adenocarcinoma / Q000145:classification / Q000473:pathology* / Q000601:surgery; D000369:Aged, 80 and over; D002280:Basal Cell Carcinoma; D006801:Humans; D007633:Keratins / Q000032:analysis; D008175:Lung Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery; D008297:Male; D009077:Mucins / Q000032:analysis; D009361:Neoplasm Invasiveness; D010641:Phenotype; D014944:World Health Organization
chemical_list: D009077:Mucins; D007633:Keratins