Challenges in the diagnosis and management of tumor-induced osteomalacia: A case report

Abstract

The present case report is aimed to highlight the difficulty and the reason for the delayed diagnosis of phosphaturic mesenchymal tumors, emphasizing the need of standardized protocols for diagnosis, surgery and follow-up in high-volume hospitals. The clinical signs and symptoms, diagnostic and therapeutic procedures, immunohistological features were analyzed. Delayed diagnosis of phosphaturic mesenchymal tumor was primarily due to non-specific clinical symptoms such as fatigue, muscular and bone pain, and multiple fractures. This cryptic clinical picture made the diagnosis tricky that led to treatment of patient for non-specific pain and stress fractures before to consider the tumor-induced osteomalacia syndrome. Some well-documented studies were found in the literature in which the history of trauma is a critical trigger of glomus tumors. Extra-subungual tumors most frequently occur in the knee and ankle regions, particularly among young adults, and the diagnosis is typically made approximately 7.2 years after initial symptom onset. The difficult tumor localization represented an additional obstacle to the prompt treatment, leading to delayed curative surgery.

Keywords: Cancer imaging; Delayed diagnoses; Glomus tumor; Phosphaturic mesenchymal tumor; Tumor-induced osteomalacia syndrome case report.

Fig. 1

Whole-body scintigraphy showing absorption of radiotracer at multiple sites.

Fig. 2

PET/CT scan showing increased uptake at tibia distal epiphysis (A). MRI imaging showing a mass at the articular surface of right tibia (B). MRI examination confirming a mass at inferior articular surface of the right tibia and the presence of lower third of tibia stress fracture (C).

Fig. 3

Microscopically, phosphaturic mesenchymal tumors consist of a hypercellular tumor composed of round cells and eosinophilyc cytoplasm at hematoxylin eosin staining (A). Low Ki67 positivity (B). Vimentin immunostaining showed focal positivity (C). Diffuse positive marking for Smooth muscle actin (D). Magnification: 20×.

Fig. 4

CD34 immunostaining highlighting the vessels present in the lesion at 10x and 20x (A and B). Negative staining for S-100 (C) and desmin (D) markers. Magnification: 20×.