Tumour-induced osteomalacia: a diagnostic conundrum

Area of Science:

• Oncology
• Endocrinology
• Orthopedics

Background:

• Phosphaturic mesenchymal tumors (PMTs) are rare neoplasms characterized by fibroblast growth factor 23 (FGF23) production.
• These tumors often lead to osteomalacia due to excessive renal phosphate wasting, presenting with non-specific symptoms that can cause diagnostic delays and prolonged patient morbidity.
• The varied histological appearance and subtle clinical presentation contribute to the challenges in diagnosing PMTs.

Purpose of the Study:

• To report a case of phosphaturic mesenchymal tumor (PMT) presenting as osteomalacia.
• To illustrate the diagnostic and management pathway for a patient with a PMT.
• To emphasize the need for established diagnostic and treatment guidelines for PMTs.

Main Methods:

• A case study of a patient with generalized body ache, weakness, and difficulty walking was investigated.
• Biochemical tests revealed increased renal phosphate wasting.
• Functional imaging (somatostatin receptor scintigraphy) and CT scan identified a lesion in the distal tibia, followed by en bloc tumor resection.

Main Results:

• The patient presented with symptoms consistent with osteomalacia and demonstrated significant renal phosphate wasting.
• Imaging successfully localized a somatostatin receptor-positive lesion in the left distal tibia.
• En bloc resection of the tumor was performed, and the patient recovered fully with oral phosphate and vitamin D supplementation at 1-year follow-up.

Conclusions:

• Phosphaturic mesenchymal tumors (PMTs) require a high index of suspicion for timely diagnosis and treatment.
• Surgical resection combined with appropriate supplementation can lead to complete recovery.
• Development of standardized diagnostic and treatment guidelines is crucial for optimizing patient outcomes and reducing morbidity associated with PMTs.