Primary phosphaturic mesenchymal tumour of the lumbar spine: utility of ⁶⁸Ga-DOTATOC PET/CT findings

Abstract

Primary phosphaturic mesenchymal tumours (PMTs) frequently occur in the soft tissue or bone, but rarely in the spine. The majority of patients experience long-term ostalgia and recurrent fractures. Detection of PMT can be challenging, but the clinical symptoms dramatically improve after removal of the tumour.Wepresent a case of primary PMT in the lumbar spine. CT scan showed a low-density tumour with a well-defined sclerotic margin in the L5 vertebra. MRI revealed a hypointense tumour on T2 weighted imaging and heterogeneous enhancement. 68Ga-labelled 1,4,7,10-tetraazacyclododecane-N,N′,N″, N‴-tetraacetic acid-D-Phe1-Tyr3-octreotide (68Ga-DOTATOC) positron emission tomography/CT scan demonstrated intense focal uptake within the tumour. Histologically, proliferation of oval to short spindle-shaped cells with fibrocollagenous stroma, abundant various-sized vessels, microcysts and thickened anastomosed bone trabeculae were seen. Mitotic figures were rarely seen. Immunohistochemically, the tumour cells were focally positive for fibroblast growth factor 23. The imaging findings in the current case are in accordance with the histological features. Among them, 68Ga-DOTATOC positron emission tomography/CT scan for somatostatin receptor imaging provides valuable information for determining PMT localization and characterization.

A 50-Year-Old Man Presenting with Multiple Bone Lesions and a Diagnosis of Phosphaturic Mesenchymal Tumor of the Femur

“…Clinically, PMT generally presents as a solitary lesion in various areas of bone, such as femur [ 25 , 26 ], tibia [ 27 , 28 ], cervical vertebra [ 29 , 30 ], lumbar vertebra [ 31 ], sacrum [ 32 ], phalanx [ 33 ], metacarpal [ 34 ], maxilla [ 20 ], and mandible [ 35 ]. Notably, Nathan et al reported a patient with the first PMT in the tibia, and the second in the maxillary sinus occurring 2 years later [ 36 ].…”

Clinical Applications of Somatostatin Receptor (Agonist) PET Tracers beyond Neuroendocrine Tumors

“…Small studies by Agrawal et al [ 46 ] and Jadhav et al [ 47 ] also reported higher sensitivity and specificity for SSTR tracers compared with [ 18 F]FDG. Multiple other case and small studies summarized in Table 2 report localization of culprit lesions in patients with TIO using SSTR tracers [ 14 , 38 , 39 , 40 , 41 , 42 , 44 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 ]. An example showing culprit lesions identified in 3 patients using [ 68 Ga]Ga-DOTATATE PET-CT from a small study by John et al [ 38 ] is shown in Figure 5 .…”

Phosphaturic Mesenchymal Tumor-induced Osteomalacia Masquerading as an Orthopedic Polytrauma Patient: A Case Report and Review of the Literature

“…Tumor cells stimulate upregulation of fibroblast growth factor 23 (FGF-23), preventing formation of 1, 25-dihydroxyvitamin D3 (calcitriol), which inhibits reabsorption of phosphate in the kidneys [ 5 , 7 , 9 , 10 ]. PMTs have been reported in bone and soft tissue, including the thigh, foot, hip, head, neck, and spine [ 1 , 2 , 3 , 4 , 5 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ].…”