Spindle cell carcinoma of the lung: Frequency, clinical features, and immunohistochemical studies of three cases

Because frequency, immunohistochemical, and clinical features of lung spindle cell carcinoma (SpCC) are unknown, the author retrospectively surveyed and re-examined the 718 lung malignancy samples in our hospital. As the results, three cases of SpCC were found; thus the incidence of SpCC was 0.4% of all lung malignancies. Clinically, the age of the patients was 53, 70 and 75 years. Two patients were smokers and another ex-smoker. The SpCC was initially detected by routine chest X-ray examination in all cases. All cases were peripheral tumors, and the size was 4 cm, 5 cm, and 5 cm in diameter. All cases were treated by chemotherapy, and operations were not performed for various reasons. The survival period was 8, 16 and 25 months. Histologically, all the three SpCC consisted of only malignant spindle cells with hyperchromatic nuclei and mitotic figures. Immunohistochemical results were as follows: pancytokeratin (3/3), high molecular weight cytokeratin (0/3), CK5/6 (0/3), CK7 (2/3), CK14 (1/3), CK18 (3/3), CK19 (1/3), CK20 (0/3), epithelial membrane antigen (0/3), vimentin (3/3), thyroid transcriptional factor-1 (0/3), p63 (1/3), CEA (0/3), surfactant apoprotein A (0/3), desmin (0/3), S100 protein (0/3), α-smooth muscle actin (0/3), CD34 (0/3), p53 protein (3/3), chromogranin (0/3), synaptophysin (0/3), neuron-specific enolase (0/3), CD56 (0/3), CD56 (0/3), KIT (0/3) and platelet-derived growth factor-α (0/3). These results suggest that SpCC of the lung shows no differentiation. One case of the three SpCC was positive for p63, suggesting that it may be derived from spindle cell differentiation of poorly differentiated squamous cell carcinoma. In summary, the present study showed the frequency (0.4%) of SpCC of the lung of all lung malignancies. Clinical features of the three SpCC were described. Further, the three cases of SpCC were immunohistochemically investigated.