Male osteoporosis and hymenoptera venom anaphylaxis [Osteoporosi maschile e anafilassi da imenotteri]

Mastocytosis is one of the rare causes of unexplained osteoporosis, above all in males. On the other hand, a strict association between severe systemic reactions after hymenoptera sting and mastocytosis was recently demonstrated. Here we report a case of unexplained severeosteoporosis with multiple vertebral fractures in a 48 years old male, which also suffered an anaphylactic reaction afterhymenoptera sting. Among laboratory tests performed to clarify the cause of osteoporosis, serum tryptaseconcentrations were determined. The value of tryptase was 43.6 μg/L, four times higher than the upper reference limit.Skin did not show abnormalities; bone marrow vertebral biopsy was not valuable, but bone marrow aspirate from iliaccrest demonstrated the presence of atypical mast cells expressing CD25; D816V mutation of KIT gene was alsoidentified. These findings, in association with an increase of serum tryptase concentrations, fulfil all minor criteriarequested for the diagnosis of systemic mastocytosis. Osteoporosis treatment with zolendronate and vitamin Dsupplementation was started, but later, for the persistence of bone pain, therapy with -interferon was added. This caseconfirms that an unexplained osteoporosis, especially if associated with hymenoptera sting systemic reaction, requiresexclusion of a systemic mastocytosis.