Diffuse Pulmonary 99mTc-MDP Uptake on Bone Scintigraphy: A Paraneoplastic Hypercalcemia Clue in Cervical Carcinoma.

Abstract

^99mTc-methylene diphosphonate bone scintigraphy is a cornerstone imaging modality for skeletal assessment; however, extraosseous radiotracer uptake may signal underlying systemic metabolic derangements. Diffuse pulmonary uptake, classically linked to metastatic calcification, is commonly observed in chronic kidney disease patients with calcium-phosphate homeostasis disruption. We present an uncommon case of bilateral pulmonary ^99mTc-Methylene diphosphonate (MDP) uptake in a 48-year-old female with advanced cervical carcinoma, renal insufficiency, and severe hypercalcemia accompanied by paradoxically normal parathyroid hormone levels. While thoracic computed tomography showed no structural abnormalities, bone scintigraphy demonstrated diffuse pulmonary radiotracer accumulation, consistent with metastatic calcification secondary to calcium-phosphate deposition within alveolar walls. This case underscores the critical need for vigilant monitoring of metabolic complications in oncology patients, especially those with renal impairment, and highlights the diagnostic value of bone scintigraphy in identifying occult extraskeletal pathologies, even when conventional imaging appears unremarkable. The findings advocate for integrating metabolic profiling with functional imaging to better understand atypical tracer uptake patterns in high-risk populations.