A 27-year-old man comes to the office due to cough, chest discomfort, and dyspnea on exertion. Symptoms began approximately a month ago and were initially mild but have gradually worsened. He has also lost 4.5 kg (10 lb) over the past 2 months. The patient has no chronic medical conditions. He smokes a pack of cigarettes a day and drinks an average of 4 beers each weekend. The patient does not use illegal drugs and has not had multiple sexual partners. Physical examination is unremarkable. Chest imaging reveals a large, anterior mediastinal mass. Subsequent blood work shows elevated levels of β-hCG and alpha fetoprotein. Which of the following is the most likely diagnosis?

Question

A 27-year-old man comes to the office due to cough, chest discomfort, and dyspnea on exertion.  Symptoms began approximately a month ago and were initially mild but have gradually worsened.  He has also lost 4.5 kg (10 lb) over the past 2 months.  The patient has no chronic medical conditions.  He smokes a pack of cigarettes a day and drinks an average of 4 beers each weekend.  The patient does not use illegal drugs and has not had multiple sexual partners.  Physical examination is unremarkable.  Chest imaging reveals a large, anterior mediastinal mass.  Subsequent blood work shows elevated levels of β-hCG and alpha fetoprotein.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_3988_7c68_9249_bdd47e96b2fe_MD0001_00 Masses that arise within the mediastinum are typically classified according to their compartment. Within the anterior mediastinum, the most common etiologies are the 4 Ts: thymoma, teratoma (and other germ cell tumors [GCTs]), "terrible" lymphoma, and thyroid neoplasm. This patient with a large, anterior mediastinal mass and elevated β-hCG and alpha fetoprotein (AFP) levels most likely has a GCT. In adults, the anterior mediastinum is the most common location for extragonadal GCTs, which may be either benign (eg, benign teratoma) or malignant (eg, seminomas, nonseminomatous GCTs). These occur predominantly in young men and can cause chest discomfort and compressive symptoms (eg, cough, dyspnea) due to mass effect on adjacent structures (eg, trachea). GCT type can usually be distinguished by differences in serum tumor markers: (Choice B) Bronchogenic cysts, congenital cysts that arise due to abnormal development of the bronchopulmonary foregut, are an uncommon cause of mediastinal mass; they are typically located in the middle (vs the anterior) mediastinum and do not cause elevated AFP and β-hCG levels. (Choice C) Lymphomas, including Hodgkin lymphoma, can arise in any of the mediastinal compartments, including the anterior mediastinum. They can cause weight loss but classically produce additional systemic symptoms (eg, fever, night sweats); they do not cause elevated AFP and β-hCG levels. (Choice F) Thymomas are a common cause of anterior mediastinal mass. However, they do not cause elevated AFP and β-hCG levels, and they are often associated with paraneoplastic syndromes (eg, myasthenia gravis). Educational objective: The most common masses in the anterior mediastinum are the 4 Ts: thymoma, teratoma (and other germ cell tumors), "terrible" lymphoma, and thyroid neoplasm. An anterior mediastinal mass with elevated serum levels of alpha fetoprotein and β-hCG is classic for a nonseminomatous germ cell tumor.

A 27-Year-Old Man Comes to the Office Due to Cough