46 Malignant Primary Adenocarcinoma of the Trachea: A Rare Diagnostic Entity. (11th January 2018) - Morris, Richard
Abstract: Primary tracheal tumors are exceedingly rare, accounting for approximately 0.1 \% of all malignancies. They can present with a variety of nonspecific symptoms, which makes them difficult to diagnose and often leads to advanced disease. Squamous cell carcinoma is the most common tracheal tumor (44–63%) followed by adenoid cystic carcinoma (7%-16%) and less commonly encountered histologies (adenocarcinoma, small cell carcinoma, and mucoepidermoid carcinoma). Here, we present an unusual case of a primary tracheal adenocarcinoma. A 64-year-old woman with a history of diabetes, GERD, and seasonal allergies, presented with coughing and shortness of breath. She was diagnosed with bronchitis and treated with antibiotics, steroids, and inhalers. A CT scan of the chest revealed a 1.1 x 0.9 x 1.0 cm tumor in the upper/mid trachea, along the left wall. The patient underwent tracheal resection with anastomosis. The specimen consisted of a segment of trachea 2.2 cm in length with a tan nodular mass 1.3 cm that appeared focally infiltrative into cartilage. Histology showed an adenocarcinoma with areas of marked pleomorphism. Resection margins and seven lymph nodes were negative. The tumor was positive for AE1/AE3, c-kit and vimentin. S100, CD43, mammaglobin, SMA, calponin, DOG-1, calcitonin, chromogranin, synaptophysin, and TTF-1 were negative. FISH was negative for rearrangement of the ETV6 gene region (at 12p13.2). The postoperative course was uneventful and no adjuvant radiation was given. Primary adenocarcinoma of the trachea is often a diagnosis of exclusion, as secondary tumors via direct extension from the bronchus, larynx, or esophagus are more common. Adenocarcinomas usually present in the lower third of the trachea, which makes this case of a mid-tracheal adenocarcinoma unique. Primary malignant tracheal tumors can pose diagnostic and therapeutic challenges because their rarity has prevented development of a standardized staging system, and only limited prognostic data are currently available to guide therapy.