A 15-year-old adolescent with no significant medical history admitted to the emergency room due to polydipsia, abdominal pain,nausea, vomiting, sudden dyspnea, and chest pain; On admission he was diagnosed with diabetic ketoacidosis in addition tospontaneous penumomediastinum by tomography. It is emphasized that pneumomediastinum associated with ketoacidosis is a rarecomplication but with a favorable evolution in most cases.  

We present the case of a 25-year-old woman with fever of unknown origin, whose cervical node biopsy study was reported as Castleman disease, but who at follow-up turned out to be multisystem tuberculosis. He received antituberculous treatment with good clinical and laboratory evolution at follow-up. It is emphasized that, in the face of diseases of low prevalence, such as Castleman disease, tuberculosis should be ruled out in countries like ours.