Sarcomatoid Carcinomas of the Lung: A Clinicopathologic Review

Abstract

Sarcomatoid carcinomas ( S O of the lung are the most common pulmonary neoplasms that exhibit a composition by spindled or pleomorphic tumor cells. As such, many of them may be confused easily with true sarcomas diagnostically unless special immunohistological or ultrastructural analyses are performed. Reactivity is expected for keratin, epithelial membrane antigen, or collagen type IV in the sarcomalike elements in SC, although it may be focal. Electron microscopy often shows the presence of junctional complexes between tumor cells, with or without pericellular basal lamina and cytoplasmic skeins of intermediate filaments. Current terminological preferences are such that several formerly used terms-including "spindle-cell carcinoma," "pulmonary blastoma," " s q u a m o u s cell carcinoma w i t h p s e u d o s a r c o m a t o u s stroma," "pseudosarcoma," and "carcinosarcoma" Therefore, a cytologically atypical spindle cell tumor of the lung is usually considered an SC unless rigorous immunohistologic and ultrastructural studies indicate otherwise. The goal of this review is to provide a discussion of neoplasms in this general category, using information taken from the pertinent literature and our personal experience. HISTORICAL AND TERMINOLOGICAL CONSIDERATIONSA historical controversy has existed about the mechanisms by which obvious foci of carcinoma of the lung are commingled with malignant but nondescript spindle cell elements or tissues with the apparent morphotype of a particular sarcoma pattern. Also, From the Lauren V.

K-ras gene mutational analysis supports a monoclonal origin of biphasic pleomorphic carcinoma of the lung

“…28 In the latter, a multistep progression of the sarcomatous component from a common totipotent ancestor through an intermediate stage of carcinoma was prospected, as these tumors showed a greater amount of genetic damages in the mesenchymal than in the epithelial component. 28 The association between smoking and pulmonary pleomorphic carcinomas is very strong, 7,14,15,17,32 as re-emphasized also by the current series of patients, in whom all but one were smokers. All K-ras mutations detected in our tumors were transversions, namely G:C-T:A in four cases and G:C-C:G in two cases, exactly paralleling the findings of previous reports showing a higher prevalence of G:C-T:A (67%) than G:C-C:G transversions (33%).…”

“…These tumors have been variously designated in the past as biphasic and monophasic sarcomatoid carcinoma, pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, pseudosarcoma, pulmonary blastoma and carcinosarcoma. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The latest recommendations of the World Health Organization have eliminated most of these terms, 1 confirming the designation of pleomorphic carcinomas to either pure neoplasms consisting of sarcomatoid spindle and giant tumor cells or biphasic neoplasms containing sarcomatoid spindle and/or giant cell components (accounting for at least 10% of the tumor mass) and conventional non-small-cell lung carcinoma, including squamous cell carcinoma, adenocarcinoma or large-cell carcinoma. These tumors may be differentiated from carcinosarcomas for the lack of a true malignant heterologous mesenchymal component, such as bone, cartilage, vessels or skeletal muscle, 10 and from pulmonary blastomas for the lack of primitive mesenchymal and epithelial tumor cells.…”

“…1,20 Pleomorphic carcinomas are basically thought to be epithelial tumors in which neoplastic cells undergo an epithelial-mesenchymal transition 21 and express vimentin and other mesenchymal proteins. 3,7,[13][14][15]17,19,22 In different anatomical sites, most, but not all, of these tumors composed of carcinoma and sarcoma or sarcoma-like components are considered monoclonal growths (the so-called divergent hypothesis) rather than true collision tumors (convergent hypothesis). 20,[23][24][25][26][27][28][29][30][31] In turn, these monoclonal growths may originate from a single ancestor undergoing divergent epithelial and mesenchymal differentiation early during the neoplastic transformation (combination theory), or the full-blown carcinoma cells undergo sarcomatoid changes during tumor progression (conversion theory).…”

Sarcomatoid Carcinoma in the Lung of an Egyptian Fruit Bat (Rousettus Aegyptiacus)

“…6 Cells in carcinomatous and sarcomatous regions stained with variable intensity using antibodies to both pancytokeratin (staining the cytoplasm; Figs. 4, 5) and S-100 (staining the nucleus, cytoplasm, and intercellular material; Figs.…”

“…6 Sarcomatoid carcinomas are generally considered to be epithelial neoplasms, which exhibit sarcomatous differentiation. 6 They have variably been described as carcinosarcoma, spindle cell carcinoma, blastoma, teratocarcinoma, pseudosarcoma, and squamous cell carcinoma with pseudosarcomatous stroma. 3,6 Pulmonary sarcomatoid carcinomas are primary neoplasms of the lung.…”