Category: Calcium/Bone Disorders

Monitor: 29

29 - Tumor-induced osteomalacia

Saturday, Apr 27
10:00 AM – 10:30 AM

Objective :

52 year old male patient presenting with osteomalacia due to phosphate wasting syndrome secondary to a suspected mesenchymal tumor.

Methods : n/a

Results :


Discussion : Case of a 52 year old male patient with past medical history of benign prostatic hyperplasia presenting with progressive symptoms of arthralgia, weakness, and non-fragility fractures. No evidence of leg bowing or short stature in physical examination. Biochemical work-up done due to hypercalcemia symptoms, revealed primary hyperparathyroidism for which parathyroidectomy of the adenoma was performed, and hypophosphatemia. Due to continued polyarthralgias imaging were done (abdominopelvic CT scan, bone scan, and skeletal survey) with evidence of a calcified left lung granuloma, inflammatory changes in both sacroiliac bones, left iliac crest bone lesion with non-diagnostic bone biopsy, left tibial osteochondroma, and left scapular lytic lesion. Bone scan showed progression of costochondral osteogenesis resembling a rachitic rosary, for which diagnosis of osteomalacia was entertained. DXA scan reveled a low BMD (T score at lumbar spine at -2.7 and Z score at -3.2) for which denosumab was prescribed. Due to persistent hypophosphatemia, elevated alkaline phosphatase, low 1,25 vitamin D, and imaging findings, patient was started on calcitriol and phosphate supplementation. He was referred to our endocrinology clinics for suspected osteomalacia. Laboratory values revealed an elevated 24-hour urine collection for phosphorous at 2,317, elevated alkaline phosphatase 433 U/L (30ng/mL), and elevated FGF23 at 1600RU/mL (<180RU/mL). After ruling out secondary causes of renal phosphate wasting and evidence of elevated FGF23, in the setting of multiple site involvement, tumor-induced osteomalacia secondary to a mesenchymal tumor was suspected. FDG-PET and octreotide scintigraphy has been negative at the moment. Phosphate supplementation optimized with clinical improvement.

Conclusion :

Tumor-induced osteomalacia lesions are typically small, benign mesenchymal tumors that may be found in bone or soft tissue, anywhere in the body. Octreotide scintigraphy is successfully used to locate tumors in up to 95% of patients. High-resolution magnetic resonance imaging of the whole body is the currently proposed method of choice to confirm the location of the tumor. Locating the tumor is critical, as complete removal is curative. In 5% of patients the tumors cannot be found; in these cases long-term medical treatment with phosphate supplements and active vitamin D is recommended with active surveillance usually successful. However medical treatment can be cumbersome and associated with complications.


Anardi A. Agosto Mujica

Endocrinology Fellow
University of Puerto Rico-Medical Science Campus
Canovanas, Puerto Rico

Doctor Agosto finished his graduate studies in the "Universidad Autonoma de Guadalajara, Mexico", followed by his speciality in internal medicine in Ponce, Puerto Rico (Hospital Damas). At the moment is a fellow resident in the University of Puerto Rico, Medical Sciences Campus, School of Medicine.

Andres J. Ortiz Nieves

University of Puerto Rico-Medical Science Campus
ponce, Not Applicable, Puerto Rico

Dr. Ortiz is a former endocrinology fellow in the University of Puerto Rico, Medical Sciences Campus, School of Medicine.

Milliette Alvarado-Santiago

Attending Physician
Univeristy of Puerto Rico- Medical Science Campus

Dr. Milliette Alvarado Santiago is an Endocrinology Specialist in Rio Piedras, Puerto Rico. She graduated with honors from University Of Puerto Rico School Of Medicine in 2010. Having more than 8 years of diverse experiences, especially in ENDOCRINOLOGY, INTERNAL MEDICINE, Dr. Milliette Alvarado Santiago has dedicated her early career to the academic field, being full time assistant professor at the Endocrinology Fellowship at the University of Puerto Rico.

Margarita Ramirez-Vick

Attending Physician
University of Puerto Rico - Medical Science Campus

Dr. Margarita Ramirez-Vick is an endocrinology specialist in San Juan, PR and has been practicing for 29 years. She graduated from University of Puerto Rico School of Medicine in 1989 and received her medical degree from University of Puerto Rico School of Medicine. She specializes in endocrinology, diabetes & metabolism.

Loida A. Gonzalez-Rodriguez

Assistant Professor
University of Puerto Rico School of Medicine - Endocrinology, Diabetes and Metabolism Division
San Juan, Puerto Rico

Loida A. Gonzalez-Rodriguez, MD is an Endocrinology, Diabetes & Metabolism specialist in San Juan, Puerto Rico. She graduated from University of Puerto Rico - School of Medicine in 2008, completed her specialty in Internal Medicine in 2011 and her sub-specialty in Endocrinology in 2014 at the University Hospital of Puerto Rico. Since then she has been Assistant Professor at the Endocrinology, Diabetes and Metabolism Division of the University of Puerto Rico. Dr. Gonzalez-Rodriguez also participates in different research projects in the area of endocrinology.