Diagnosis

The differential diagnosis based on the imaging findings included ossification of subperiosteal hematomas, ectopic calcification in the setting of a connective tissue disorder, and periostitis deformans secondary to fluoride intoxication. Laboratory assays were requested by the patient’s rheumatologist, which were notable for a mildly elevated alkaline phosphatase level (216 U/L, reference range=40–115 U/L) and a markedly elevated serum fluoride level (3.9 mg/L, normal range <0.2 mg/L), confirming the diagnosis of fluoride intoxication. The findings were discussed with the patient, who admitted to chronically “huffing” Freon, or inhaling the chlorofluorocarbon gas from a plastic bag.