Reversibility in male idiopathic osteoporosis possible.

Summary: A 44-year-old athletic man presented in 2009 with severe low back pain. Dual-energy x-ray absorptiometry revealed severe osteoporosis; serum testosterone was 189 ng/dL while serum estradiol (E2) measured by liquid chromatography/mass spectrometry was 8 pg/mL. DNA was extracted and sequenced from a blood sample from the patient since his maternal first cousin also had low bone mass and both patients were screened for aromatase dysfunction by PCR analysis for the CYP19A1 gene, which encodes aromatase. No known pathologic mutations were observed in the coding exons, but novel single nucleotide polymorphisms were detected both in the proband and in his cousin. Treatment with topical testosterone started in August 2010. Over the next 8 years, testosterone dosage was varied and switched from topical gel to injections and maintained on depo-injections of testosterone at about 60 mg once per week. Re-examination in March 2012 included a brain MRI to exclude pituitary lesions; hyperparathyroidism was ruled out (normal serum parathyroid hormone, calcium, and calcium to phosphorous ratio) and celiac disease was excluded (negative transglutaminase antibodies). Follow-up in October 2018 showed improved bone mineral density of the lumbar spine by 29% and of the left femoral hip by 15% compared to baseline measurements. This reveals the importance of measuring serum E2 for making the correct diagnosis, as well as for monitoring a therapeutic effect. Herein, we propose treatment of male osteoporosis where serum E2 levels are below about 20 pg/mL with testosterone to reverse osteoporosis. Learning points: Estrogen deficiency in the diagnosis of male idiopathic osteoporosis. Importance of serum estradiol in male osteoporosis. Role of polymorphisms in aromatase gene on bone health. Reversal of osteoporosis. Tailored testosterone treatment for bone health.