Endocrine Abstracts

Collision tumors (CT) refers to the coexistence of two histologically distinct malignant tumors within the same mass. CT involving the thyroid gland (TG) and/or the neck are specially uncommon and present a diagnostic and treatment challenge.

Case report: A 69-year-old male presented with a one year history of bilateral cervical lymph node growth, a four-month history of progressive dysphagia and a dyspnea associated with a rapidly expanding, painless mass in the right side of the neck. He denied smoking, exposure to radiation or history of cancer. A physical examination revealed a firm, immovable 5 cm mass in the right side of the neck and a firm, fixed 8 cm mass in the right TG. A computed tomography scan inform a mass in the right lobe of the TG, infiltrating parapharyngeal spaces, airway compression, with supraclavicular extension and enlarged lateral bilateral lymph nodes in the neck. The laryngeal biopsy reported, connective tissue infiltrated by papillary carcinoma of probable thyroid origin, and US-FNA reported papillary carcinoma thyroid. The patient underwent total thyroidectomy combined with incisional laryngeal biopsy as well as paratracheal lymph node and bilateral selective neck dissection, tracheostomy was performed. The laryngeal biopsy specimen revealed a laryngeal squamous cell carcinoma. The right lobe of the thyroid gland contained a tall cell variant of papillary thyroid carcinoma with invasion and penetration of regional soft tissues and laryngeal mucosa. Sectioning of multiple bilateral cervical lymph nodes revealed metastases from the thyroid papillary carcinoma and squamous cell carcinoma.The diagnosis was a collision tumor from a tall cell papillary thyroid carcinoma and a laryngeal squamous cell carcinoma. After one month, laryngectomy was performed, a mass of 4 cm was reported with focus on the oropharynx with extension towards the tongue and the larynx and with carcinomatous lymphangitis.The histopathological diagnosis was collision tumor originating from a tall cell papillary thyroid carcinoma and a laryngeal squamous cell carcinoma. The patient presented with a expanding painless, firm and fixed 7 cm mass, in the in the middle neck, at one month post-surgery and he start palliative treatment with radiotherapy and cisplatin. After one more month, the patient has acute dyspnea with blood secretions from the tracheostomy and he died.

Conclusion: Management of collision tumor is complex because the duality of the pathology, treatment should be patient specific. Generally, the most aggressive neoplasm should guide treatment.