A 76-year-old man was referred to our hospital for investigation of a 20-day history of rapidly deteriorating dyspnea and severe cough. This was associated with dysphagia and cervical pain. The patient was an ex-marble craftsman and an active smoker. His medical history included chronic pulmonary obstructive disease (COPD). A chest X-ray (CXR) showed an imprint at the right side of the trachea. Thyroid ultrasound (US) revealed a large and heterogenous thyroid gland and the presence of a calcified mass, 4.76 × 4.01 cm with high blood perfusion in the right upper lobe of the gland. A contrast-enhanced computed tomography (CT) scan of the neck and thorax reported the corresponding lesion as heterogenous, with irregular borders, extending from the sternoclavicular joints to the upper borders of the thyroid gland. The mass was surrounding the trachea anterolaterally displacing it to the left and the right common artery to the right (). There were no enlarged lymph nodes. Bronchoscopy revealed a fracture of the first tracheal ring but there was no evidence of tumour invasion (). Cytology from bronchial lavage was negative for cancer cells. Laboratory tests were within normal limits with the exception of elevated D-dimers (2,994 μg/L) and elevated white blood cells (19.27 K/μL). Tumour markers were within normal range values.\nOn admission, the patient was intubated, due to acute respiratory failure, and he was admitted to the intensive care unit (ICU). Subsequently, he underwent an emergency procedure and a collar incision was carried out. At surgery, a suspicious looking tumour, which was in continuity with the superior pole of the right thyroid lobe, the sheath of right common carotid artery, and the anterolateral portion of the cartilaginous trachea, was identified. Macroscopically, the tumour looked whitish and scleroelastic with moderately regular borders and was firmly adhered to the aforementioned structures. After the right recurrent laryngeal nerve was identified, the tumour was carefully dissected off the right thyroid lobe and the adventitia of the right common carotid artery. A similar approach was carried out to dissect the tumour off the left lobe; hence, an en bloc tumour resection with total thyroidectomy and a regional lymph node dissection was performed. Rapid frozen section biopsy of the tumour in the right thyroid lobe proved to be malignant with features of squamous cell carcinoma and negative surgical margins.\nPostoperatively, the patient experienced swallowing difficulty and hoarseness and a tracheostomy was performed on day 2.\nFinal pathology examination confirmed frozen section's diagnosis of a squamous cell carcinoma invading the right lobe of the thyroid gland, as well as extracapsular structures of the left lobe. Microscopically, the tumour was described as nonencapsulated, irregularly lobulated, with broad fibrous septa, and lymphoplasmacytic, eosinophilic, histiocytic, and multinuclear infiltration. The neoplastic cells were largely polyhedral or oval with eosinophilic or amphophilic cytoplasm, arranged in islands or nests that showed focal keratinization. The nuclei were vesicular or hyperchromatic with nucleoli. A panel of immunohistochemical stains was performed; the tumour was positive for p63, CD117, CKH, CD5, and CD3 in the lymphocytic part (Figures , , and ). It was also negative for the expression of TTF1.\nThe patient subsequently improved and was discharged home on postoperative day 20. The patient did not receive any additional treatment.
A 60-year-old woman, who was diagnosed with cancer of the thyroid gland in 2015, was treated with total thyroidectomy and lymph node dissection. Her postoperative pathology showed carcinoma showing thymus-like differentiation (CASTLE). She was discharged on Levothyroxine 100 mg/day. She did not attend her follow-up appointments. After 2 years, the patient found a lump in the left side of her neck. The tumor grew very slowly and did not cause any symptoms; hence, she did not seek medical advice. In May 2020, about 3 years after the appearance of her left neck tumor, the patient was admitted to our hospital with shortness of breath due to tracheal compression from the tumor. Clinical examination showed enlarged solid painless cervical lymph nodes at levels III and IV, stuck in a block size of 3 × 6 cm in diameter. There was no involvement of the hypopharynx, and her vocal cords were intact. CT scan of her neck revealed a 16 × 54 mm lesion compressing the trachea, and several enlarged left cervical lymph nodes with the size of about 25 mm (Fig. ). The patient was offered a tracheostomy and tracheal stent before undertaking further investigations.\nHer subsequent fluorine-18-labeled fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) scan revealed previous total thyroidectomy, no evidence of recurrence in the surgical bed, enlarged left cervical lymph nodes at levels III and IV, and extranodal extension into sternocleidomastoid muscle measuring 29 × 43x59 mm, with the maximum standardized uptake value (SUV max) of 6.8. Her thymus measured 19 × 31x37mm, with increased metabolism of FDG (SUV max 3.6). There was a 33 × 39x49 mm mass on the left side of the anterior mediastinum, showing an undefined margin with neighboring organs in the trachea and the thorax (SUV max 6.0). It also showed multiple lymph nodes near the lower trachea, next to the superior vena cava, posterior thymus, and aortic loop; the largest node was 26 × 40 mm, with increased metabolism of FDG (SUV max 7.9). The other organs were unaffected. There was no metastasis in other organs (Fig. ).\nThyroid function tests showed TSH: 0.00726 mIU/L[0,4-5], FT4: 22.34 pmol/L [12-22] and FT3: 4.0 pmol/L [1, 3-3, 1]. We reviewed the pathology of the current cervical lymph node specimen and that of the thyroid specimen from 5 years ago (2015). This showed that the thyroid tumor consisted of invasive cells which were poorly differentiated with squamous cell morphology, different from conventional thyroid carcinoma. The immunohistochemistry (IHC) analysis showed positive staining with CK5, CK7, p63, C-kit, CD5 and negative with TTF-1, Thyroglobulin, GATA3, ER, CD99, and NKX2.2, confirming CASTLE pathology in both the specimens.\nThe patient was diagnosed with a recurrence of the CASTLE thyroid gland in cervical lymph nodes. She was assessed by thoracic, and head and neck surgeons for the possibility of removing the maximum of recurrent tumors. However, it was considered a difficult, high-risk procedure; she and her family declined to go ahead with the surgery. Then, we offered the patient treatment with palliative radiotherapy. However, she and her family declined the treatment and got the patient discharged from the hospital. She was followed up without intervention and is currently stable 15 months after the recurrence.