Oncogenic osteomalacia: localization of underlying peripheral mesenchymal tumors with use of Tc 99m sestamibi scintigraphy.

OBJECTIVE: To highlight a strategy for potential detection of mesenchymal tumors in oncogenic malacia, as illustrated by 3 cases. METHODS: Three case reports are presented in which successful localization of the offending neoplasm was accomplished by using whole-body Tc 99m sestamibi scanning. Alternative localization techniques are also reviewed. RESULTS: Oncogenic osteomalacia occurs infrequently and is caused by neoplasms that secrete phosphatonins, substances that interfere with proximal tubular resorption of phosphorus and can result in phosphaturia, hypophosphatemia, reduced 1,25-dihydroxyvitamin D concentration, and osteomalacia. Removal of the underlying neoplasm results in complete resolution of all biochemical, pathologic, and physical manifestations of this disorder, as shown in our 3 patients. Because the neoplasms are small and can occur in any tissue compartment, they are difficult to localize, a feature that often results in therapeutic failure. CONCLUSION: We conclude that use of whole-body Tc 99m sestamibi scanning may be an appropriate and cost-effective initial strategy for the localization of peripheral phosphatonin-secreting tumors.

Osteomalacia after Roux-en-Y gastric bypass.

OBJECTIVE: To emphasize the potential for Roux-en-Y gastric bypass treatment of morbid obesity to result in late development of metabolic bone disease and to illustrate the error of treating a low bone mineral density with bisphosphonates in the presence of unrecognized osteomalacia. METHODS: We conducted a retrospective case review of clinical, laboratory, and radiologic details in a patient who underwent Roux-en-Y gastric bypass as well as a review of the literature relative to metabolic bone disease associated with bariatric surgical procedures. RESULTS: A 42-year-old woman was diagnosed with high bone turnover osteoporosis and failed to respond to bisphosphonate (alendronate) therapy. Her past medical history included corticosteroid-dependent asthma and a Roux-en-Y gastric bypass surgical procedure for obesity approximately 6 1/2 years before the current assessment. Evaluation revealed vitamin D deficiency in conjunction with pronounced secondary hyperparathyroidism and biochemical evidence of osteomalacia. Aggressive calcium and vitamin D supplementation corrected the vitamin D-deficient state and was accompanied by rapid improvement in clinical symptoms, biochemical variables, and bone mineral density. CONCLUSION: This case exemplifies two principles: (1) the potential for a Roux-en-Y gastric bypass surgical procedure to lead to the development of metabolic bone disease and (2) the importance of recognizing mineralization defects as a cause for low bone mineral density, before initiation of therapy with bisphosphonates.

The American College of Endocrinology and Endocrine University.

Subspecialty training in endocrinology depends in part on local expertise, with fellows having "hands-on" experience in some areas but only "book knowledge" in others. To provide more uniform training in new technologies, The American College of Endocrinology developed Endocrine University, which provides on-site didactic and interactive sessions on thyroid ultrasound, bone densitometry, and other topics over 6 to 7 days. The inaugural event in 2002 was attended by 137 fellows. A second conference in 2003 had capacity attendance of 143. A third course is scheduled for 2004. Fellows pay a token registration fee; the College provides grants to defray the cost of registration, travel, etc. Financial support comes from the College and industry, with plans for an endowment to sustain the program. Fellows value the educational sessions and also the unique opportunity to meet and visit with their peers. This innovative program can serve as a model for other specialties.