Osteoporosis with vertebral fractures in young males, due to bone marrow mastocytosis: a report of two cases.

Male osteoporosis in young patients is an unusual condition, always worth investigating as a possible manifestation of secondary osteoporosis. Mastocytosis is a clonal disorder of mast cells with heterogeneous presentations; when pathologic cells accumulate only in the bone marrow, vertebral fractures and systemic osteoporosis may represent the sole clinical presentation at the onset of the disease. We report on two young male patients who came to our attention because of multiple dorsal and lumbar vertebral fractures, with no other signs of systemic mastocytosis (SM). Lumbar and femoral dual x-ray absorptiometry showed reduced bone mineral density values; biochemical investigations did not report significant anomalies, suggestive of secondary osteoporosis. One of the patients underwent iliac crest bone biopsy, which was not diagnostic. A vertebral intralesional CT-guided bone biopsy was performed in both patients, which allowed the diagnosis of SM. Our experience pointed out that bone biopsy still remains the gold standard for the diagnosis of SM. However, iliac crest biopsy can be not significant because of circumscribed bone marrow involvement: in these cases only intralesional bone biopsy could be diagnostic.