A 6-year-old child from rural Maharashtra presents with a 3-week history of low-grade fever and mild cough. Chest X-ray shows a small calcified nodule in the mid-zone of the right lower lobe with calcified hilar lymph nodes. The child is asymptomatic otherwise and has normal sputum smear microscopy. The radiological findings represent the structure marked **C** in the diagram. Which of the following BEST describes the pathological significance of this finding?