About 1 month ago, a 58-year-old man experienced malaise and fatigue accompanied by mild diffuse swelling in his neck. After 3 days, the malaise and fatigue began to abate. They resolved after a week; however, minimal swelling on the left side of the neck remains. The patient has no other symptoms.
Two years earlier, squamous cell carcinoma of the larynx was diagnosed; the tumor was excised and radiation therapy given. The rest of his medical history is unremarkable. He smokes a pack of cigarettes daily and drinks alcohol(Drug information on alcohol) socially.
The patient is slightly overweight. Temperature is 37.2oC (99oF); heart rate, 92 beats per minute; respiration rate, 18 breaths per minute; and blood pressure, 138/92 mm Hg. Heart and lungs are normal, as is the oral cavity. Examination of the neck reveals mild fullness without significant tenderness on the left side at the level of the mandible, along the jugular chain of lymph nodes; inferior extension may be present.
A CT scan is ordered to evaluate the soft tissues of the neck. Although the CT images obtained before the patient's surgery 2 years earlier are not available, the radiologic report describes minimal fullness of the larynx on the left side (the site of the primary tumor) and no evidence of adenopathy.
New CT images at the level of the mandible and at the level of the submandibular glands reveal prominent lymph nodes lateral to the left internal jugular vein and posterior to the vessels deep to the left sternocleidomastoid muscle (Figure 1). These lymph nodes measure less than 1 cm in short axis; 1 cm or greater is the CT criterion for designating a lymph node abnormal. However, the patient's nodes demonstrate decreased central density—especially the node in the posterior triangle.
Which diagnostic test would you order next and why?
WHICH TEST—AND WHY: A positron emission tomography (PET) scan is the best test to determine whether the tumor has recurred and, if it has, to assess the extent of disease. Because the patient currently has no symptoms other than mild neck swelling, the key concern is recurrence of the squamous cell carcinoma of the neck. Decreased central density on CT suggests more active pathology than a node with homogeneous soft tissue density.