Rare Case of Progressive Osteolysis and Chylothorax in an Adolescent Male.

An 18-year-old man with no prior medical history presented to the tertiary care center with a 6-month history of progressively worsening bone pain. The pain was localized to the right posterior ribs, mid-thoracic spine, and right iliac bone and was described as deep, throbbing, and exacerbated by physical activity, which significantly limited his mobility. Concurrently, he reported recurrent episodes of dyspnea and chest tightness, particularly in the supine position. Physical examination revealed reduced tactile fremitus and diminished breath sounds over the bilateral lower lung fields, with dullness to percussion. Bilateral pitting edema extended from the ankles to the knees (grade 1+), with no signs of joint swelling, skin rash, or lymphadenopathy. Vital signs were notable for low-grade fever (38.2 °C) and tachycardia (heart rate: 92 beats/min).