Paradoxic technetium-99 methylene diphosphonate localization in malignant mesothelioma

The literature is replete with cases of Tc-99m bone imaging agent uptake in pleural effusions. Far rarer is the report of photopenia in a pleural effusion. In this case of malignant mesothelioma, we describe a unique case of unilateral hemithoracic photopenia from a pleural effusion with concomitant uptake in the contralateral lung resulting from calcified pleural plaques. Although initially perplexing clinically, this case can be readily explained with an understanding of basic physiological principles.