Intrapulmonary Mercury Deposition more than a Decade after Ingestion of a Mercury-Containing Traditional Remedy: A Case Report.

Isolated intrapulmonary metallic density nodules are rare clinical findings. Elemental mercury deposition in the lung parenchyma is exceptionally uncommon and is typically associated with intravenous injection or occupational exposure. Cases resulting from oral ingestion with latency periods exceeding a decade present significant diagnostic challenges. A 52-year-old male farmer presented with an incidentally discovered thoracic opacity on imaging. Chest computed tomography revealed a solitary hyperdense nodule with a precise attenuation of 2809 Hounsfield Units located in the posterior basal segment of the left lower lobe. The patient denied typical mercury exposure but recalled ingesting a traditional medicine explicitly stated to contain mercury over ten years prior for joint pain. During video assisted thoracoscopic surgery, the lesion was identified within the lung parenchyma. Intraoperative fluoroscopy confirmed the metallic content in the resected specimen. Gross examination revealed silvery liquid mercury pooling within the lesion. Histopathological analysis demonstrated granulomatous inflammation with black particulate deposits, and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy identified characteristic mercury peaks within these deposits, confirming localized mercury deposition. Notably, comprehensive evaluation revealed that systemic blood and urinary mercury biomarkers remained strictly within normal limits. This case demonstrates that localized pulmonary mercury deposition following oral exposure can remain entirely asymptomatic and eventually manifest solely as an incidental radiological finding more than a decade later. Precise preoperative localization of highly dense lesions near the diaphragm can be challenging. The integration of intraoperative fluoroscopy and a detailed traditional medicine history is crucial for an accurate diagnosis. This report highlights the silent but enduring health risks associated with the unregulated use of heavy metals in traditional remedies.