Description 

A 94-year-old man presented with complaints of increasing fatigue and generalised weakness for 1 month’s duration. On admission, the patient had tachycardia of 112 bpm and fever of 101.1 °F. His initial physical examination was otherwise normal. Lactic acid was elevated (4.13 pg/mL), but other laboratory markers were within normal limits. No apparent source of infection was identified by initial urinalysis, chest radiography or CT of the abdomen without contrast. The lactic acidosis resolved after administration of normal saline, but he continued to have fever, which prompted more thorough physical examination that revealed a painless right-sided neck mass. CT of the neck without contrast confirmed a low-density neck mass in the right posterior cervical region measuring 7 cm in the maximum diameter (figures 1 and 2), suspicious for necrotic tumour or an abscess. Ultrasound-guided drainage of the mass recovered 50 mL of purulent material that was submitted for microbiological analysis and cytology. The sample contained inflammatory cells and debris, but was negative for malignancy. Numerous acid-fast bacilli (AFB) were identified on AFB smear, …