A 58-year-old man presented to us three years ago with a history of progressive anterior neck swelling and hoarseness of voice for the past one month. On clinical examination, there was palpable left anterior neck swelling with cervical lymphadenopathy. A core needle biopsy of the lesion revealed invasive poorly differentiated carcinoma. He defaulted our follow-up and opted for a left hemithyroidectomy at another institution. The histopathological report was intrathyroid thymic carcinoma. He refused adjuvant radiotherapy despite being counselled and subsequently defaulted follow-up.\nRecently, the patient presented to us again with progressive hoarseness of voice and intermittent haemoptysis. He had shortness of breath, especially when lying flat, but no difficulty in swallowing. On clinical examination, there was a left supraclavicular mass measuring 2 × 2 cm. The mass was immobile and hard in consistency. The anterior aspect of the neck showed an irregular hard mass measuring 3 × 4 cm. An indirect laryngoscopy examination revealed a left vocal cord palsy, likely from his previous presentation. An intraluminal mass was seen over the posterior tracheal wall, occupying a third of the tracheal lumen. We proceeded with a contrasted computed tomography (CECT) of the neck and thorax, which revealed a lobulated hypodense soft tissue mass measuring 4.3 × 3.9 × 5.2 cm. It occupied the left thyroid bed from the C7/T1 to the T2/T3 vertebral level, with left retrosternal extension and tracheal deviation to the right. The soft tissue mass had displaced the left common carotid artery and internal jugular vein laterally. As the CECT showed (, ), the soft tissue mass had caused more than 80% of tracheal luminal narrowing. At retrosternal, multiple matted lymph nodes were seen.\nImage-guided fine needle aspiration cytology (FNAC) of the soft tissue mass at the left thyroid bed showed malignant cells suggestive of intrathyroid thymic carcinoma (CASTLE). After a multidisciplinary meeting, we planned for curative resection and tracheostomy. Intraoperative tracheoscopic examination showed a soft tissue mass measuring 3 cm in length at the posterior tracheal wall, 2.1 cm from the vocal cord (). The mass was debrided to achieve an adequate diameter of tracheal lumen distal to the tracheostomy insertion. The left supraclavicular solid tumour densely adhered to the left great vessels. Due to a high risk of injury to the great vessels, we proceeded with tumour debulking only.\nThe histopathology report showed an unencapsulated tumour that displayed lobular architecture. The tumour lobules were composed of sheets of neoplastic polygonal cells rimmed by a variable amount of mature lymphocytes. The neoplastic cells were mildly pleomorphic, and lymphovascular invasion was present. Skeletal muscle bundles attached at the periphery showed focal tumour cell infiltration (, ). Immunohistochemical studies were immunoreactive for CD5 (membranous pattern) and CD117 but negative for thyroglobulin and TTF1 (, ). The proliferative index, Ki67, was approximately 20%.\nPostoperative care was unremarkable, and no immediate complications were noted. The patient was counselled for adjuvant chemoradiotherapy, but he was not amenable to this course of action. He is currently under regular follow-up with no disease progression six months after the operation.
A 60-year-old gentleman with past medical history of cervical disk herniation presented with a 3-year history of progressive fatigue and bilateral upper extremity weakness. MRI was performed to evaluate the spine and was consistent with cervical spinal stenosis. T2 non-contrast images incidentally revealed an infiltrating mass in the left thyroid that was incompletely visualized. Ultrasound-guided fine needle aspiration showed atypia of undetermined significance. The patient was referred to surgery and was noted to have dysphonia but no stridor or dysphagia. The differential diagnosis was felt to include papillary thyroid carcinoma, follicular thyroid carcinoma, rare thyroid neoplasms including Hurthle cell carcinoma or anaplastic carcinoma, abscess, or autoimmune thyroid disease. He underwent total thyroidectomy with central neck dissection. On exploration, the thyroid mass was seen encasing the left recurrent laryngeal nerve and was shaved off the nerve and the trachea. The nerve was not stimulatable after resection and the patient developed left vocal cord paralysis. The tumor grossly measured 7 cm with extrathyroidal extension. There was lymphvascular space invasion and perineural invasion. Three lymph nodes were identified, and all were negative. Surgical margins had extensive involvement of tumor. Histopathologic analysis of the specimen showed high-grade carcinoma with thymus-like differentiation. Immunohistochemical staining was positive for pan-CK, p63 (cyokeratin and epithelial markers) and negative for chromogranin, thyroglobulin, and calcitonin (neuroendocrine, papillary and follicular thyroid, and medullary makers, respectively).\nThe tumor was arranged in broad, pushing, smooth-bordered islands abutted against a lymphocyte rich stroma. The lobules of tumor were surrounded by lymphocytes and plasma cells (Figures and ). The tumor cells were squamoid and syncytial to spindled, with eosinophilic cytoplasm, and the nuclei show mild pleomorphism with pale vesicular chromatin. The neoplastic cells were strongly immunoreactive for pancytokeratin and p63, as shown in Figures and . These cells were also strongly positive for CD5, which marks background T lymphocytes (Figure ). The neoplastic cells were non-reactive with TTF1 and thyroglobulin.\nPostoperative staging surveillance with PET scan was performed for systemic staging and due to positive margins. It showed no abnormal FDG uptake at distant sites and increased uptake at the operative bed, indeterminate between residual disease and postoperative changes. The patient underwent adjuvant treatment with radiation therapy to 64 Gy in 32 fractions with intensity modulated radiotherapy. Concurrent chemotherapy was given based on his extensive positive margins for radiosensitization. A dose of 60 Gy was delivered to the bilateral neck including paratracheal nodes into the upper mediastinum, with a 4 Gy sequential boost to the operative site. A coronal section of the radiotherapy plan is shown in Figure . Six cycles of intravenous concurrent cisplatin 35 mg/m2 were infused. During therapy, he developed grade 2 skin reaction characterized by dry desquamation and moderate erythema of the neck and upper chest. Skin moisturizer was used for therapy. He experienced grade 2 esophagitis and mucositis of the oropharynx and grade 2 nausea requiring topical analgesics, oral narcotics, antiemetics, and intravenous fluid administration. Weight decreased from 108 to 95.5 kg by the end of therapy. Nutritional counseling by dietician and oral nutritional supplementation were provided. With chemotherapy, the patient developed a tinnitus grade 1. Toxicities are reported per the Common Terminology Criteria for Adverse Events ().\nAfter treatment, the patient initially experienced continued weight loss, and as a result underwent percutaneous endoscopic gastrostomy tube placement. Five months after end of treatment, the tube was removed after the patient was able to gain significant weight and completely obtain nutrition per oral route for 6 weeks. Dysphagia to solid foods is improving. He experienced persistent dysphonia secondary to left vocal cord paralysis since surgery and underwent left medialization thyroplasty 1 year later. He displayed improvement in voice quality. At 3-years follow-up after completion of radiotherapy, our patient is without evidence of locally recurrent or distant disease.