Purpose: This case report describes an unusual presentation of diffuse pulmonary uptake of Tc-99m dicarboxypropane diphosphonate (Tc-99m DPD), attributed to pulmonary microcalcification resulting from coronary stent thrombosis. Materials and Methods: A 64-year-old man with hypertension, hyperlipidemia, and a previous drug-eluting coronary stent placement underwent Tc-99m DPD bone scintigraphy for suspected avascular necrosis of the femoral head. Results: Bone scintigraphy revealed focal uptake in the femoral head, indicative of avascular necrosis, as well as unexpected diffuse pulmonary uptake of Tc-99m DPD. These findings were interpreted as evidence of pulmonary microcalcification secondary to coronary stent thrombosis, likely due to microembolic vascular inflammation and subsequent calcium deposition. Conclusion: This case highlights the diagnostic utility of detecting extraosseous radiotracer uptake and emphasizes the need to correlate nuclear imaging results with cardiovascular history to identify systemic disease manifestations.