A recurrent craniopharyngioma illustrates the potential usefulness of urinary matrix metalloproteinases as noninvasive biomarkers: case report.

OBJECTIVE: Matrix metalloproteinases (MMPs) are a class of enzymes involved in angiogenesis, tumor growth, and metastasis. Recent reports indicate that urinary MMPs predict the presence of several types of tumors, including those of the breast, prostate, and bladder. Ongoing protocols at our institution are evaluating the efficacy of urinary MMPs as diagnostic markers for brain tumors and gastrointestinal disease.

CLINICAL PRESENTATION: An 8-year-old girl underwent transsphenoidal resection of a craniopharyngioma at the age of 6 years with radiographic gross total resection. Two years later, her urine was analyzed for MMPs as part of an evaluation for gastrointestinal complaints. Despite normal gastrointestinal evaluation results, her urinary MMP levels were markedly elevated. She subsequently sought treatment for recurrent craniopharyngioma.

INTERVENTION: The craniopharyngioma was resected again. Approximately 1 year after surgery, no sources of the elevated MMPs have been found other than the recurrent craniopharyngioma. Follow-up analysis of urinary MMPs demonstrated clearing of markers concordant with tumor treatment.

CONCLUSION: We report the finding of elevated urinary MMPs in the setting of a recurrent craniopharyngioma. These biomarkers correlate with the presence of disease, clear with treatment, and can be tracked from source tissue to urine. The findings of this case support the hypothesis that urinary MMPs may be a useful predictor of the presence or recurrence of brain tumors. To our knowledge, this is the first report supporting the proof-of-principle concept that urinary MMPs may have potential usefulness in predicting the presence of brain tumors, expanding the spectrum of tumors capable of being diagnosed with this technique.