PMC5173502_01
CT scans of the primary tumor. (A) Before treatment. (B) 1 week after chemoradiotherapy. (C) 15 months after chemoradiotherapy. The diameter of the tumor was reduced from 40x22 mm (A) to 19x9 mm (B) and to 9x4 mm (C). The size of the lymph node under the carina was also reduced. No recurrent lesion was detected.
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The CT scan revealed two masses in his chest: a mass measuring 40x22 mm in size behind the main trachea (Fig. 1A) and a mass measuring 12x5 mm in size below the carina. After the treatment, a CT scan showed a significant reduction in both the primary tumor and the swollen lymph node (Fig. 1B), and the response was judged to be a partial response by Response Evaluation Criteria in Solid Tumours (RESIST) version 1.1. After chemoradiotherapy, he underwent two courses of adjuvant chemotherapy with carboplatin (AUC 6) and paclitaxel (300 mg/body). He has had no recurrence of either sarcomatoid carcinoma or hepatic cell cancer for 15 months after the chemoradiotherapy (Fig. 1C), and no late toxicity has been observed.
Endoscopic pictures. (A) Gastrointestinal fiberscopy revealed no lesion in the esophagus. (B) Bronchoscopy revealed a tumor growing from the membranous portion of the trachea.
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Gastrointestinal fiberscopy revealed no lesion in the esophagus (Fig. 2A). Bronchoscopy revealed a tumor growing from the membranous portion of the trachea (Fig. 2B), and a biopsy was conducted from that region.
Histological examination. (A) Hematoxylin and Eosin staining, x200. (B) Immunohistochemistry (IHC) for thyroid transcription factor-1 (TTF-1), x200. TTF-1 positivity suggests that the tumor is derived from lung tissue. (C) IHC method for vimentin, x200. Vimentin positivity can be a marker for diagnosis of sarcomatoid carcinoma.
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A histological examination showed the presence of spindle-shaped cells, and a differential diagnosis of sarcomatoid carcinoma and synovial sarcoma was made (Fig. 3A). Staining for thyroid transcription factor-1 (TTF-1, Fig. 3B) was positive, which suggested a primary lung tumor. Staining for vimentin, which is used as a marker of mesenchymal-derived cells, was partly positive (Fig. 3C).
Radiotherapy planning. (A) Plan for first course of 40 Gy. (B) Plan for second course of 20 Gy with reduction of dose to the spinal cord.
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The planning target volume (PTV) was a 5-mm circular margin added to CTV (Fig. 4A). The beams were carefully arranged to avoid the spinal cord during the next treatment course (Fig. 4B).