A 52-year-old woman was referred to our hospital because of severe dyspnea and the presence of a neck tumor. She had experienced dyspnea for the past 6 months and had recently noticed bloody sputum. A computed tomography examination of the neck revealed a thyroid tumor about 8 cm in size. The tumor had invaded the trachea, obstructing 90% of the tracheal lumen (fig. ). An emergency tracheotomy was performed to maintain an airway through the tumor tissue. On biopsy, the tumor was diagnosed as CASTLE, suggesting a favorable prognosis if a complete resection could be performed. Magnetic resonance imaging and an esophageal fibroscopy examination revealed a low possibility of esophageal invasion (fig. ). Under general anesthesia, a thyroidectomy was initially performed via a neck incision. The invaded portion of the trachea was sharply dissected. A partial sternotomy was performed at the level of the 2nd intercostal space to identify the distal portion of the intact trachea and to mobilize the inferior tracheal segment. The trachea was transversely opened to find the intact portion. The length of the resected trachea was 6 cm (fig. ). Bilateral recurrent nerves were macroscopically preserved. We performed a suprahyoid release to mobilize the superior tracheal segment, but these mobilizations were insufficient to perform an anastomosis. Thus, to allow additional mobilization, we performed a clamshell thoracotomy and incised the pericardium 360° around the hilum, dissecting the pulmonary ligament bilaterally. These procedures allowed an anastomosis. An end-to-end bronchial anastomosis was carried out using running 4-0 PDS II sutures (Ethicon, Somerville, N.J., USA) for the membranous portion and interrupted 4-0 PDS II sutures for the cartilaginous portion. The bronchial anastomosis was wrapped with an omental pedicle flap that was lifted up through a retrosternal route via a laparotomy. A gastrostomy was also performed for postoperative enteral nutrition. For management after surgery, a chin suture was placed. Neck mobilization was restricted for the placement of the chin suture and airway fixation. After confirming an improvement in the laryngeal edema using a laryngoscopy, extubation was performed on postoperative day (POD) 17. The patient exhibited swallowing disturbances and underwent swallowing rehabilitation. Enteral nutrition was provided through the gastrostomy. The patient was discharged on POD 31, and per os feeding was started on POD 51. Radiotherapy (60 Gy in 40 daily fractions of 1.5 Gy) was performed as an adjuvant therapy. Throughout the clinical course, no major complications, including swallowing disturbances, hoarseness or anastomotic problems, were observed. A histopathological examination of the resected specimen revealed the characteristic morphology of CASTLE (fig. ); immunohistochemistry was positive for CD5 (fig. ) but negative for thyroid transcription factor 1 (TTF-1; fig. ).\nEleven months after surgery, lower back pain and right leg numbness developed and led to gait inability. Multiple lung and bone recurrences were observed, but no local recurrence. In order to ease the back pain, palliative radiotherapy (35 Gy in 14 fractions) to the bone metastasis was administered. Twelve months after surgery, drainage of pleural effusion was performed. She died of pleural metastasis 14 months after the initial diagnosis of CASTLE.
The patient, a 28-year-old man with a 3-month-old mass in the neck was referred to our department. The mass, located on the left thyroid lobe, was elastic, hard, showed limited mobility, and measured approximately 30 × 20 mm. There was no remarkable tenderness over the mass.\nBlood examination results were normal, including levels of thyroid-stimulating hormone, free thyroid hormone, and thyroglobulin (Table ). Ultrasonography revealed a hypoechoic solid mass in the lower pole of the left thyroid lobe with a poorly marginated heterogeneous pattern (Fig. ). Computed tomography revealed a heterogenic tumor in the left thyroid lobe (Fig. ). 18F-fluorodeoxyglucose (18F-FDG) accumulated in the thyroid tumor on positron-emission tomography. The standardized uptake value of 18F-FDG was 5.29 (Fig. ). Fine-needle aspiration cytology (FNAC) showed a number of lymphoid cells without atypia that were similar to those seen in malignant lymphoma of the thyroid (Fig. ).\nAs we diagnosed a highly malignant thyroid cancer (cT2N0M0), we performed a left hemithyroidectomy with central neck dissection (ND). Histopathological findings showed that the tumor was composed of irregular insular nests of neoplastic cells and had an expansive growth pattern in the thyroid (Fig. ). The carcinoma cells had round nuclei or polymorphonuclei with well-defined nucleoli and ill-defined cell borders (Fig. ). Immunohistochemical studies showed that the tumor was partially positive for CD5, positive for Ki-67 (approx. 30%), and negative for CD20, calcitonin, and thyroglobulin (Fig. ). Based on these histopathological findings, the tumor was finally diagnosed as CASTLE. There were no signs of recurrence without additional treatment after 10 years of follow-up.