HMMA is also an acronym for hydroxy-methylmandelate (or 4-hydroxy-3-methoxymandelate), a metabolite of epinephrine, whose presence in the urine is used as a fairly low sensitivity approach to diagnosis phaeochromocytoma. It has now been largely abandoned as a diagnostic tool as other metabolites, such as VMA and metanephrins, are more sensitive. - Source: Wikipedia