Collision tumor versus multiphenotypic differentiation: a case of carcinoma with features of colonic and lung primary tumors.
BACKGROUND
Collision tumors are rare tumors composed of two histologically distinct neoplasms coinciding at the same location. Collision tumors need to be distinguished from tumors originating from a progenitor cell with potential for multiphenotypic differentiation.


METHODS
A clinically puzzling case of an intricate malignant pulmonary nodule in a patient with previous history of colorectal carcinoma is reported. A brief review of the clinical literature on collision tumor and tumor stem cells is presented.


CONCLUSIONS
This case report emphasizes the importance of detailed histopathologic and immunohistochemical analyses, and clinical history in diagnosing a tumor composed of multiple malignant morphologies.
Murthaiah
Pradeep
P
Division of Hematology, Oncology and Transplantation, University of Minnesota, 420 Delaware Street SE, MMC 480 Minneapolis, MN 55455, U.S.A.
Truskinovsky
Alexander M
AM
Shah
Saira
S
Dudek
Arkadiusz Z
AZ
D000368:Aged; D002454:Cell Differentiation; D003110:Colonic Neoplasms / Q000473:pathology*; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D010641:Phenotype