A melting, encapsulated, calcified pulmonary nodule in a healthy 51-year-old woman: a case report

BACKGROUND: Foreign body aspiration is less common in healthy adults, which makes diagnosis difficult. Early detection of smaller/sharp foreign bodies in the distal airway is more difficult because patients might have no symptoms and imaging studies could appear normal. Here we describe the course of a small, sharp foreign body (chicken bone) lodged in the distal airway of a healthy middle-aged woman. The chicken bone was initially thought to be an old calcified tuberculoma. However, it was encased in a dilated bronchus without obvious surrounding lymphadenitis or parenchymal infiltration, and it melted with time. Two years later, histopathological examination revealed that the calcified lesion was an aspirated chicken bone with a concomitant tuberculoma. CASE PRESENTATION: A 51-year-old woman showed an old calcified tuberculoma in the upper right lung lobe during routine examinations. It was “encased” in a dilated bronchus, although it was not raised from the surrounding lung parenchyma. The size of the calcified part decreased (“melted”) with time, and the surrounding inflammation progressed 2 years later, a phenomenon never described in association with tuberculosis. Bronchoscopy revealed a fragment of chicken bone lodged in the next two branches of the upper right posterior bronchus. Surgical segmentectomy was performed, and histopathological examination revealed that the calcified lesion was formed by a fragment of chicken bone as well as a tuberculoma. Eventually, the patient recalled an episode of choking on a chicken bone 5 years ago; she believed that she had coughed it out completely at that time. CONCLUSIONS: The “melting” and “encased” phenomena observed in the present case could be useful imaging findings for early detection of small foreign body aspiration in the distal airway.