Unexpected (Tco4-)-Tc-99m Uptake By Lung Adenocarcinoma

A 76-year-old woman underwent (TcO4-)-Tc-99m thyroid scintigraphy to clarify thyrotoxicosis. In addition to suppressed thyroid uptake, an atypical tracer accumulation appeared on already know pulmonary adenocarcinoma in the left lung upper lobe. Surgical pathology was reviewed confirming the diagnosis of lung adenocarcinoma with focal mucins production and excluding a misdiagnosed differentiated thyroid carcinoma metastasis.