Diagnosis Of Phosphaturic Mesenchymal Tumor Research Articles

Phosphaturic mesenchymal tumor: A chondromyxoid fibroma-like type.

Phosphaturic mesenchymal tumor (PMT) is a rare neoplasm that causes tumor-induced osteomalasia (TIO) in most affected patients, usually through the production of fibroblast growth factor 23 (FGF23). This tumor is often misdiagnosed due to its relative rarity and its widely varied histomorphologic spectrum. Here we describe a case of a 78-year-old woman who presented with a left middle tumor without symptoms of TIO. The histological features resembled chondromyxoid fibroma with smudgy calcification in the tumor matrix. In addition, we evaluated FGF23 expression through immunohistochemical study and reverse transcription polymerase chain reaction. PMT with chondromyxoid fibroma features are extremely rare. Examining the expression of FGF23 is useful in the diagnosis of PMT.

Unexpected Phosphaturic Mesenchymal Tumor of the Femoral Head.

Osteonecrosis of femoral head (ONFH) is clinically common and easily diagnosed via imaging examination, especially when there is a definite cause, such as a fracture, long-term hormonotherapy, etc. However, some rare neoplastic lesions of the femoral head can mimic its image performance in some situations, leading to misdiagnosis. We present the case of a 57-year-old male with bone pain in the left hip joint that persisted for 2 years. CT and MRI images were performed and both were suggestive of ONFH. Unexpectedly, the histopathologic results of left proximal femur resection revealed the diagnosis of phosphaturic mesenchymal tumor (PMT), a rare mesenchymal tumor. His hip pain was obviously relieved after surgery, and the course of 1-year follow-up was uneventful.

Phosphaturic Mesenchymal Tumors: Rethinking the Clinical Diagnosis and Surgical Treatment

The diagnosis of phosphaturic mesenchymal tumors (PMT) is easily delayed clinically, and their surgical treatment is unstandardized. This study aimed to evaluate our experience in the diagnosis and treatment of PMT and provide a research basis for the accurate and standardized treatment of PMT. Twelve patients diagnosed with PMT in our department and who underwent surgical treatment were included in this study. Preoperative demographic and clinical information were recorded. CT, MRI, and technetium-99m (Tc99m)-octreotide PET/CT imaging techniques were used to evaluate the general conditions and lesion boundaries of the tumors. Surgical treatment was performed using radical resection and microwave ablation-assisted extended curettage according to the lesion location and size. Patients were strictly followed up with and evaluated for oncological prognosis, radiological results, bone healing, serum ion levels, limb function, and pain level; the occurrence of complications was also recorded. Three patients underwent radical resection, and nine underwent microwave ablation-assisted extended curettage. The average duration of symptoms in this group was 1.5 years (9-35 months) before diagnosis. Serum phosphate and AKP levels returned to normal one and two weeks postoperatively, respectively. There was no apparent specificity in the pathological findings; however, the immunohistochemistry of FGF-23 was positive, and the original fracture sites were effectively healed during the follow-up. The limb function and pain scores were significantly improved. The MSTS score increased from 15.3 to 29.0, and the VAS score decreased from 5.3 to 0.4. All patients recovered, and 90% resumed their original jobs. Accurate diagnosis and standardized surgical treatment are crucial to achieving a clinical cure for PMT. Combining clinical manifestations, biochemical examinations, imaging characteristics, and pathological findings is an effective way to diagnose PMT accurately. Radical resection and microwave ablation-assisted extended curettage are reliable surgical treatment methods for PMT.

Phosphaturic Mesenchymal Tumor; A Diagnostically Elusive Cause Of Oncogenic Osteomalacia; Case Study

Abstract Casestudy: Phosphaturic mesenchymal tumor (PMT) is a rare, benign neoplasm. It is associated with oncogenic osteomalacia, a paraneoplastic condition caused by secretion of a peptide hormone-like substance, fibroblast growth factor 23, which increases renal clearance of phosphate and increased mobilization of calcium and phosphate from bone. PMT is difficult to diagnose as a primary etiology because patients usually experience non- specific symptoms associated with hypophosphatemia like bone pain, muscular weakness, and pathologic fractures. Because PMT is a benign neoplasm, surgical excision is curative and rapid resolution of symptoms typically ensues. Discussed here is a case of PMT arising in the soft tissue of the medial thigh of a 65 year old man with a five year history of osteomalacia with pathologic fractures and complicated healing. Lab studies revealed hypophosphatemia, hyperphosphaturia, hypercalcemia, and elevated serum fibroblast growth factor 23 during workup for fracture. A small superficial soft tissue mass was discovered in the proximal thigh via octreotide scan which was subsequently excised. On histologic examination it was composed of an encapsulated proliferation of spindle cells in a chondromyxoid background with distinctive areas of flocculent calcification and osteoclast-like giant cells. A diagnosis of PMT was rendered. The patient’s symptoms resolved rapidly after surgery. Despite the benign characteristics and behavior of this rare neoplasm; delayed or mis-diagnosis can have severe implications for patient’s health. Interdisciplinary communication, shrewd clinical index of suspicion, and awareness of the causes of, and the tests available to diagnose oncogenic osteomalacia can speed accurate diagnosis leading to better outcomes for patients.

Phosphaturic mesenchymal tumor

Phosphaturic mesenchymal tumors (PMTs) are very unusual tumors, commonly associated with tumor induced osteomalacia (TIO). The tumor cells produce a peptide hormone-like substance known as fibroblast growth factor 23 (FGF23), which regulates phosphate levels. When FGF23 is over expressed by the tumor cells it leads to phosphaturia, which inturn causes mobilization of calcium and phosphate from bones, and decreased osteoblastic activity, which finally leads to severe osteomalacia. Usual presentation of PMT will be gradual muscular weakness and diffuse bone pain from pathologic fractures. The majority of PMTs are benign, malignant PMTs are extremely rare, but exist. However, very rarely PMT present without phosphaturia and TIO i.e., the nonphosphaturic variant. The challenge in diagnosis of PMT is due to the vague nature of the symptoms and lack of clinical suspicion. The diagnosis is often missed due to the rarity of PMTs. The usual location for PMT involves the extremities followed by head and neck sites. We report a case of a 37 year old male who presented to the outpatient department with a swelling in the left parotid region. He had no associated symptoms. CT scan showed a well-defined heterogeneous mass measuring 2.3 × 2.0 cm with calcification and soft tissue density seen superficially in the left pre auricular region. Per operatively the tumor was found to be intramuscular, embedded in the left masseter muscle. The final histopathology report was confirmative of phosphaturic mesenchymal tumor.

Phosphaturic mesenchymal tumor of the nasal cavity and paranasal sinuses: A clinical curiosity presenting a diagnostic challenge

Phosphaturic mesenchymal tumor (PMT) is a rare mesenchymal neoplasm associated with tumor-induced osteomalacia (TIO) and elevated serum FGF-23. Common in extremities, PMT rarely occurs in sinonasal region. We report a series of sinonasal PMT diagnosed at our institute over a 6-year period.Six cases of sinonasal PMT were identified during this period, of which five presented with features of TIO. Median age of patients was 45.5 years. All six tumors were composed of stellate to spindled cells, with prominent staghorn vasculature in four cases. Typical smudgy matrix was seen in all cases, but only focally; grungy calcification was absent.Accurate diagnosis of PMTs is imperative, as complete excision leads to dramatic resolution of TIO symptoms. Lack of knowledge of this entity prevents clinicians from ordering relevant investigations. Absence of specific morphological features, like grungy calcification, and presentation at atypical locations makes the diagnosis challenging. Awareness of this entity is essential in order to suspect PMT in patients presenting with a soft tissue mass and features of TIO, however unusual the location may be.

Characterization of FN1–FGFR1 and novel FN1–FGF1 fusion genes in a large series of phosphaturic mesenchymal tumors

AbstractPhosphaturic mesenchymal tumors typically cause paraneoplastic osteomalacia, chiefly as a result of FGF23 secretion. In a prior study, we identified FN1–FGFR1 fusion in 9 of 15 phosphaturic mesenchymal tumors. In this study, a total of 66 phosphaturic mesenchymal tumors and 7 tumors resembling phosphaturic mesenchymal tumor but without known phosphaturia were studied. A novel FN1–FGF1 fusion gene was identified in two cases without FN1–FGFR1 fusion by RNA sequencing and cross-validated with direct sequencing and western blot. Fluorescence in situ hybridization analyses revealed FN1–FGFR1 fusion in 16 of 39 (41%) phosphaturic mesenchymal tumors and identified an additional case with FN1–FGF1 fusion. The two fusion genes were mutually exclusive. Combined with previous data, the overall prevalence of FN1–FGFR1 and FN1–FGF1 fusions was 42% (21/50) and 6% (3/50), respectively. FGFR1 immunohistochemistry was positive in 82% (45/55) of phosphaturic mesenchymal tumors regardless of fusion status. By contrast, 121 cases of potential morphologic mimics (belonging to 13 tumor types) rarely expressed FGFR1, the main exceptions being solitary fibrous tumors (positive in 40%), chondroblastomas (40%), and giant cell tumors of bone (38%), suggesting a possible role for FGFR1 immunohistochemistry in the diagnosis of phosphaturic mesenchymal tumor. With the exception of one case reported in our prior study, none of the remaining tumors resembling phosphaturic mesenchymal tumor had either fusion type or expressed significant FGFR1. Our findings provide insight into possible mechanisms underlying the pathogenesis of phosphaturic mesenchymal tumor and imply a central role of the FGF1-FGFR1 signaling pathway. The novel FN1–FGF1 protein is expected to be secreted and serves as a ligand that binds and activates FGFR1 to achieve an autocrine loop. Further study is required to determine the functions of these fusion proteins.

The Phosphaturic Mesenchymal Tumor: Why is Definitive Diagnosis and Curative Surgery Often Delayed?

Tumor-induced osteomalacia is a paraneoplastic syndrome resulting in renal phosphate wasting and decreased bone mineralization. Phosphaturic mesenchymal tumors represent a rare etiology of tumor-induced osteomalacia. Nonspecific symptoms of fatigue, bone pain, and musculoskeletal weakness make the diagnosis elusive and lead to a delay in surgical treatment. In this case series, the following three questions were asked: (1) How do the clinical presentation and features of phosphaturic mesenchymal tumors delay the diagnosis? (2) What is the clinical course after surgical treatment of phosphaturic mesenchymal tumors? (3) How frequently do phosphaturic mesenchymal tumors recur and are there factors associated with recurrence? This study retrospectively reviewed the cases of five adults diagnosed and treated for phosphaturic mesenchymal tumors. Patients were identified through an internal orthopaedic oncology database with clinical, surgical, and histologic data obtained through a systematic chart review. Five patients presented with a long-standing history of osteomalacia, generalized fatigue, pain, and weakness before the diagnosis was reached at an average of 7.2 years (range, 2-12 years) after initial symptom onset. The diagnosis appeared to be delayed owing to the cryptic medical presentation, difficulty in locating tumor by imaging, and confirming histologic appearance. Two patients treated with wide surgical resection did not experience recurrence compared with three patients who did show recurrent signs and symptoms after marginal excision. A postoperative increase in fibroblast-derived growth factor-23 was associated with recurrent disease. Although uncommon, the diagnosis of phosphaturic mesenchymal tumor should be considered in any patient who presents with hypophosphaturic osteomalacia and no other physiologic cause. Definitive treatment is early, wide surgical resection.

Diagnosis of phosphaturic mesenchymal tumor (mixed connective tissue type) by cytopathology

Oncogenic osteomalacia (OO) is a rare paraneoplastic condition in which a bone or soft tissue tumor induces biochemical and clinical signs and symptoms of osteomalacia (or rickets) most often by the production of the phosphaturic protein, fibroblast growth factor-23. Phosphaturic mesenchymal tumor, mixed connective tissue type (PMTMCT) is a rare, histologically distinct tumor that represents the most common cause of OO. As the clinical diagnosis of OO is typically suspected on the basis of clinical and biochemical features and the presence of a bone or soft tissue tumor, cytologic examination might potentially provide the necessary pathologic confirmation of OO. In this case of a 46-year-old female with clinical stigmata of OO and a right distal humeral mass, we report that the fine-needle aspiration findings of short, cytologically bland spindled cells embedded in a fine, fibrillary stromal-rich matrix and the presence of osteoclast-type giant cells associated with the stromal matrix provide strong pathological evidence for PMTMCT and assist in pathologically confirming the clinical impression of OO, thus alleviating the need for a more invasive diagnostic surgical procedure.

RT-PCR Analysis for FGF23 Using Paraffin Sections in the Diagnosis of Phosphaturic Mesenchymal Tumors With and Without Known Tumor Induced Osteomalacia

Phosphaturic mesenchymal tumors of the mixed connective tissue type (PMTMCT) are extremely rare, histologically distinctive neoplasms, which cause tumor-induced osteomalacia (TIO) in most cases through the elaboration of a phosphaturic hormone, fibroblast growth factor-23 (FGF23). Rarely, identical tumors without known TIO may be observed. We studied a large group of PMTMCT for expression of FGF23, using a novel reverse transcription polymerase chain reaction (RT-PCR) assay for FGF23 in formalin-fixed, paraffin-embedded tissues. Twenty-nine PMTMCT (17 with and 12 without TIO) and 23 non-PMTMCT (16 various mesenchymal tumors, including 5 chondromyxoid fibroma, 8 chondroblastoma, 1 hemangiopericytoma, 1 aneurysmal bone cyst, and 1 high grade sarcoma; 5 carcinomas; and 2 non-neoplastic tissues) were retrieved. Total RNA was extracted from formalin-fixed, paraffin-embedded sections for RT-PCR analysis. FGF23 was amplified using 3 sets of primers that spanned the intron/exon boundaries to amplify the 3 exons of FGF23 gene (140, 125, and 175 bp). The housekeeping gene phosphoglycerokinase (189 bp) was coamplified to check the RNA quality. Sixteen of 17 (94%) PMTMCT with TIO were FGF23-positive. Nine of 12 (75%) PMTMCT without TIO were FGF23-positive. Two chondromyxoid fibroma and 1 aneurysmal bone cyst were positive; all other non-PMTMCT were negative. We conclude that RT-PCR for FGF23 is a sensitive and specific means of confirming the diagnosis of PMTMCT both in patients with and without TIO. FGF23 gene expression was present in more than 90% of PMTMCT with known TIO, confirming the role of FGF23 in this syndrome. Rare FGF23-negative PMTMCT with known TIO likely express other phosphaturic hormones (eg, frizzled-related protein 4). Our finding of expression of FGF23 in 75% of histologically identical tumors without known TIO confirms the reproducibility of the diagnosis of PMTMCT, even in the absence of known phosphaturia.