A case report of phosphaturic mesenchymal tumor-induced osteomalacia

Unusual presentation of tumor-induced osteomalacia mismanaged due to misdiagnosis: A literature review based on a case report

Key Clinical Message

Tumor-induced osteomalacia is a rare but potentially serious disease with nonspecific misguiding manifestations that can result in a wrong diagnosis and being treated for rheumatologic or other similar diseases. In patients with unexpected fractures, resistant musculoskeletal pains, and hypophosphatemia, this diagnosis should be considered by the physicians and approached through a complete history taking, physical exam laboratory, and radiologic evaluation to give the opportunity of on-time treatment to the patient.

Abstract

Tumor-induced osteomalacia (TIO) is an uncommon mesenchymal tumor that results in disproportionate phosphorus excretion, primarily leading to bone-related symptoms. Laboratory, imaging, and histopathological evaluation can confirm this pathologic condition. In this case, we present the history and subsequent clinical parts of a 50-year-old woman who presented with an unusual presentation of generalized musculoskeletal pains and a right ankle mass. Her disease was diagnosed with multidisciplinary evaluation and was approached by a surgical treatment. The patient was treated with total resection of the tumor, which led to complete resolution of musculoskeletal and metabolic abnormalities, which were resolved following total tumor resection. TIO is a paraneoplastic disease that results in abnormal secretion of phosphatonins, particularly fibroblast growth factor 23 (FGF23). This can cause hypophosphatemia, hyperparathyroidism, lower bone density, and increased risk of pathologic fractures. These tumors are mostly cured by surgical ± radiotherapy. The present study aims to provide insight into the fact that a TIO diagnosis is not always straightforward. However, in suspicious cases such as unexplained hypophosphatemia, it should be considered to prevent delayed diagnosis of the progressive pathology. The earlier treatment can prevent several complications and reduce the risk of mortality.

The Nose that Broke the Hip! Tumor Induced Osteomalacia Secondary to Phosphaturic Mesenchymal Nasal Tumor : A Case Report

Tumor induced osteomalacia is a rare paraneoplastic syndrome caused by usually small mesenchymal tumors. The tumors are commonly located in the extremities whereas occurrence in the nasal cavity is quite rare. An 18 year old male presented with asymmetric weakness of both lower limbs and difficulty in walking since one year. On evaluation he was found to have open femur head physes and iliac apophyses, low serum Phosphorus, low vitamin D, normal serum calcium, elevated PTH & alkaline phosphatase levels. FGF-23 levels in serum were elevated. DOTA NOC PET CT revealed tumor in the left nasal cavity abutting the nasal septum. Surgical excision of the tumor resulted in normalisation of the serum levels of phosphorus, vitamin D and FGF-23. This case report indicates the importance of maintaining high clinical suspicion and early detection of causative tumor using appropriate imaging techniques.

Supernumerary derivative 22 chromosome resulting from novel constitutional non-Robertsonian translocation: t(20;22)-Case Report

Background

Maternal non-Robertsonian translocation-t(20;22)(q13;q11.2) between chromosomes 20 and 22resulting in an additional complex small supernumerary marker chromosome as derivative (22)inherited to the proband is not been reported yet.

Case presentation

A 4 years old boy with a history of developmental delay, low set ears, and facial dysmorphism was presented to the genetic clinic. Periauricular pit, downward slanting eyes, medially flared eyebrows, downturned mouth corners, and micrognathia were observed. He had congenital heart defect with atrial septal defect (ASD), ventricular septal defect (VSD), and central nervous system (CNS) anomalies with the gross cranium. Karyotype analysis, Fluorescent in-situ hybridization analysis (FISH), and Chromosomal microarray analysis (CMA) were used to determine the chromosomal origin and segmental composition of the derivative 22 chromosome. Karyotype and FISH analyses were performed to confirm the presence of a supernumerary chromosome, and Microarray analysis was performed to rule out copy number variations in the proband's 22q11.2q12 band point. The probands' karyotype revealed the inherited der(22)t(20;22)(q13;q11.2)dmat. Parental karyotype confirmed the mother as the carrier, with balanced non-Robertsonian translocation-46,XX,t(20;22)(q13;q11.2).

Conclusion

The mother had a non-Robertsonian translocation t(20;22)(q13;q11.2) between chromosomes 20 and 22, which resulted in Emanuel syndrome in the proband. The most plausible explanation is 3:1 meiotic malsegregation, which results in the child inheriting derivative chromosome. The parental karyotype study aided in identifying the carrier of the supernumerary der(22), allowing future pregnancies with abnormal offspring to be avoided.

Tumor-induced osteomalacia - a mystery illness beyond aches, pains, and depression

Objective. Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterized by chronic hypophosphatemia and osteomalacia. We present case of a patient with a protracted clinical course of TIO. TIO profoundly affected every aspect of his life with subsequent profound physical and psychosocial disabilities. Method. The review of a complex clinical presentation, serial laboratory investigations, and imaging modalities of a patient with TIO caused by a mesenchymal tumor. Results. The patient presented with chronic lower back pain, severe bilateral leg weakness, and multiple pathological fractures due to severe osteoporosis. His investigations revealed hypophosphatemia, low 1,25 dihydroxyvitamin D, phosphaturia and normal serum calcium, and parathyroid hormone. Elevated fibroblast growth factor 23 (FGF23) confirmed the diagnosis of TIO and ⁶⁸Ga-DOTATATE-positron emission tomography/computed tomography (PET/CT) imaging correctly identified a tumor in the left femoral head. His clinical features and biochemical abnormalities promptly recovered after successful surgical resection of the mesenchymal tumor. Conclusion. The present case demonstrated the need to extensively investigate causes of generalized bone pain in patients with hypophosphatemia, as TIO is highly curable. Importantly, ⁶⁸Ga-DOTATATE PET/CT imaging successfully identified the FGF23 producing tumor, which was undetectable by conventional imaging, favoring its early use in suspected TIO presentation. The present report highlights the importance of timely diagnosis of this complex medical condition, aiming to improve general awareness and enable better clinical outcomes for this rare disorder.

Clinicopathological Significance of Papillary Thyroid Carcinoma Located in the Isthmus: A Meta-Analysis

BACKGROUND

The thyroid isthmus is located directly anterior to the trachea and is covered by the strap muscles. Several studies have suggested that papillary thyroid carcinoma (PTC) in the isthmus is more aggressive and is associated with a poor prognosis. The purpose of this meta-analysis was to assess the clinicopathological characteristics and recurrence rates of PTC in the isthmus compared to PTC at other sites.

METHODS

Relevant articles were obtained by searching the PubMed database. A meta-analysis was performed using 11 eligible studies.

RESULTS

The rate of extrathyroidal extension was 0.502 (95% confidence interval [CI]: 0.239-0.764) and 0.454 (95% CI: 0.331-0.582) for isthmus PTC and PTC at other site, respectively; however, the difference in the rates was not statistically significant. Lymphovascular invasion did not significantly differ between isthmus PTC (0.179 [95% CI: 0.102-0.297]) and PTC at other sites (0.114 [95% CI: 0.066-0.188]). The rate of central lymph node (LN) metastasis was significantly higher in isthmus PTC (0.527 [95% CI: 0.435-0.617]) than in PTC at other sites (0.352 [95% CI: 0.280-0.432]). No significant difference was observed between the two groups in terms of lateral cervical LN metastasis rate. Isthmus PTC was more likely to have a prominent recurrence rate (0.046 [95% CI: 0.022-0.094]) than PTC at other sites (0.010 [95% CI: 0.001-0.070]); however, the difference was not statistically significant (because of the small number of included studies).

CONCLUSIONS

The results of this meta-analysis indicated that isthmus PTC was associated with an increased risk of central LN metastasis. Isthmus PTC seems to have a slightly higher recurrence rate than PTC at other sites. Therefore, considering the potential of the isthmus location as an unfavorable factor, more attention should be focused on isthmus PTC, and a more aggressive approach such as prophylactic central LN dissection might provide better outcomes in PTC management.

The phosphaturic mesenchymal tumor as a cause of oncogenic osteomalacia. Three cases and review of the literature

INTRODUCTION

The phosphaturic mesenchymal tumour (PMT) is a very uncommon cause of oncogenic osteomalacia (OO), which is a paraneoplastic syndrome with severe clinical osteomalacia. The PMT is a neoplasia that produces the fibroblast growth factor FGF23, resulting in reduced proximal tubular phosphate reabsorption leading to hyperphosphaturia and hypophosphatemia. Our aim is to present our experience and complications in diagnosis and treatment of PMT in three patients.

MATERIAL AND METHODS

We propose an observational, descriptive and retrospective study of three cases of OO secondary to PMT found in our database of bone and soft tissue tumours. The inclusion criteria were: symptoms related with OO, presence of hyperphosphaturic hypophosphatemia, elevated levels of FGF23 in blood and pathological diagnosis of PMT.

RESULTS

In all cases, the disease showed asthenia, non-specific bone pain, progressive functional weakness, and pathological fractures. The average delay time in diagnosis was 7 years. All presented with hyperphosphaturic hypophosphatemia, elevated levels of alkaline phosphatase as well as FGF23. The use of Octreoscan and PET-CT were essential to find the producing tumour and its subsequent biopsy. Treatment was surgery in two cases and one case was treated by CT-guided cryotherapy with neurophysiological control. Once the surgery was performed, the blood parameters normalized. There is no recurrence.

CONCLUSIONS

Phosphaturic mesenchymal tumor is a very rare entity as part of bone and soft tissue tumors, it may occur in both tissues. The phosphate-calcium homeostasis is altered due to high serum levels of FGF23 because of PMT. Delay in diagnosis is usual, leading to renal and skeletal comorbidities. To avoid this, knowledge of this entity together with high diagnostic suspicion are critical. Surgical treatment leads to normalization of serum levels and systemic symptoms.

Performance of 68Ga-DOTA-SST PET/CT, octreoscan SPECT/CT and 18F-FDG PET/CT in the detection of culprit tumors causing osteomalacia: a meta-analysis

Objectives

The objective of this study was to assess and compare the performance of ⁶⁸Ga-DOTA-conjugated-somatostatin-receptor-targeting-peptides (⁶⁸Ga-DOTA-SST) PET/CT, octreoscan-SPECT/CT and ¹⁸F-FDG-PET/CT in the detection of tumor-induced osteomalacia (TIO).

Methods

Relevant studies reporting the performance ⁶⁸Ga-DOTA-SST PET/CT, octreoscan-SPECT/CT and ¹⁸F-FDG-PET/CT in TIO were identified by searching PubMed, EMBASE, and Web of Science (last updated June 2019). Two authors independently extracted the numbers of true and false positives, and true and false negatives. The pooled estimates on a per-patient basis were calculated with 95% confidence interval (CI) obtained using a random-effects model.

Results

Fourteen studies comprising 346 patients were included in this meta-analysis. The meta-analysis provided the following results on a per-patient analysis. The pooled sensitivities of both ⁶⁸Ga-DOTA-SST PET/CT (90%, 95% CI 82–95%) and octreoscan-SPECT/CT (83%, 95% CI 75–89%) were found to be significantly higher (P < 0.005) than that of ¹⁸F-FDG PET/CT (67%, 95% CI 53–80%). There was no statistically significant difference between the sensitivity of ⁶⁸Ga-DOTA-SST PET/CT and octreoscan-SPECT/CT (P = 0.161). Owing to the low number of articles with true negative findings, the pooled specificities were not calculated. A total of 287 tumors were identified in 287 patients according to the data the included studies offered. The majority of the tumors were located in the lower extremities (59.6%, 171/287), followed by craniofacial regions (24.0%, 69/287), torso (9.4%%, 27/287), and upper extremities (6.9%, 20/287).

Conclusion

This meta-analysis demonstrates that somatostatin receptor-based imaging modalities outperformed ¹⁸F-FDG PET/CT in the detection of TIO, with ⁶⁸Ga-DOTA-SST PET/CT performing slightly better than octreoscan-SPECT/CT.

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Left maxillary sinus tumour-induced hypophosphataemic osteomalacia and combined with thyroid papillary carcinoma: a case report and literature review

Tumour-induced osteomalacia (TIO) is a rare disease characterised by hypophosphataemia and clinical symptoms of osteomalacia. Herein we report the case of a 29-year-old man who was admitted to hospital with progressive bone pain and was diagnosed with TIO caused by maxillary sinus tumours. In the preoperative evaluation, it was found that the patient had thyroid malignant tumours at the same time. Two operations were performed separately on the left maxillary sinus tumour and thyroid tumour after complete examination. After tumour resections, the symptoms of bone pain were relieved and the level of blood phosphorus was restored, long-term replacement therapy was needed for thyroid. When a patient is diagnosed with TIO, it is necessary to screen for the presence of other malignant tumours and explore the treatment options in order to benefit patients preferably.

Surgical treatment of recurrent spinal phosphaturic mesenchymal tumor-induced osteomalacia: A case report

RATIONALE

Tumor-induced osteomalacia (TIO) is a highly unusual disease with enormous difficulties in clinical diagnosis and curative managements. The objective of this study is to report a very rare case who underwent surgical treatment of recurrent spinal phosphaturic mesenchymal tumor. The management of these unique cases has yet to be further elucidated.

PATIENT CONCERNS

A 52-year-old man presented with a 3-year history of back pain and 1-year history of continuous and progressive systemic bone pain. The patient, who had been diagnosed of TIO for 3 years, received surgical treatment of extended resection of spinal phosphaturic mesenchymal tumor at L5. Somatostatin receptor tomography revealed the expression of somatostatin in the spine increased significantly, with high suspicion of recurrent phosphaturic mesenchymal tumor.

DIAGNOSIS

Magnetic resonance imaging of spine and positron emission tomography-computed tomography showed the mass in L5, which was highly indicative of the recurrent pathogenic tumor. Postoperative pathology confirmed the diagnosis of phosphaturic mesenchymal tumor in the spinal region.

INTERVENTIONS

The patient underwent posterior L5 tumor resection, bone cement reconstruction, L4-S1 spinal canal decompression, and L3-S2 internal fixation.

OUTCOMES

The patient's symptoms improved significantly after the surgery, and we noticed that his hypophosphatemia was successfully corrected after the 2nd operation. Follow-up at 1 month after surgery revealed no recurrence, and the serum phosphorus level of the patient turned to be normal postoperatively. There were no complications associated with the operation during the follow-up period.

LESSONS

Taken together, the lesion's clinical features, imaging results, and pathologic characteristics are unique. Combined efforts of specialists from orthopedics, endocrinology, nuclear medicine, radiology, pathology, and medical oncology led to the successful diagnosis and management of this patient. TIO, although rare, should be part of the differential diagnosis when the patient has a history of hypophosphatemia and systemic multiple bone pain. We recommend surgical treatment of the phosphaturic mesenchymal tumor in the spinal region. Osteoplasty by bone cement may be a treatment option for patients with TIO who cannot undergo appropriate surgery or decline open surgery.

Successful treatment of tumor-induced osteomalacia causing by phosphaturic mesenchymal tumor of the foot

Tumor-induced osteomalacia causing by phosphaturic mesenchymal tumor of the foot is exceedingly rare, thus may bring great challenges to the timely and proper diagnosis and treatment of clinicians. The only definitive management is removal of the phosphaturic mesenchymal tumor completely. The objective of this article is to report 2 unusual cases with tumor-induced osteomalacia causing by phosphaturic mesenchymal tumor of the foot.We describe 2 patients with phosphaturic mesenchymal tumor involving the foot who were successfully treated with tumor resection. On presentation to our institution, the patients both had signs of severe osteomalacia, and the patients' most outstanding complaints were diffuse bone pain, general weakness, and disabled walking. A 53-year-old female underwent surgical excision of pathogenic tumor on the sole of left foot. A 62-year-old female underwent complete excision of pathogenic tumor of right plantar. The patients showed appropriate destruction of the tumor, adequate pain relief, and the elevated blood phosphorus levels compared with the previous status.Surgical resection is the most effective treatment option for patients with tumor-induced osteomalacia who can undergo appropriate surgical treatment. This represents a safe and reasonable approach to sustainably relieve pain and other symptoms with tumor-induced osteomalacia in the foot.

Review of paraneoplastic syndromes in children

Paraneoplastic syndromes are defined as clinical syndromes that are not related to direct tumor invasion or compression but are secondary to tumor secretion of functional peptides/hormones or related to immune cross-reactivity with normal host tissue. Paraneoplastic syndromes have a wide range of presentations and can present before the primary malignancy or tumor recurrence is diagnosed. They can mimic non-neoplastic processes, making detection, diagnosis and treatment difficult. However, they can also provide clues to the presence of an underlying malignancy. In this paper, we reviewed a range of paraneoplastic syndromes that can occur in children including: (1) neurologic (opsoclonus-myoclonus, limbic, anti-N-methyl-d-aspartate [NMDA] and anti-Ma2 encephalitis and myasthenia gravis); (2) endocrine (neuroendocrine tumors, hypercalcemia, SIADH [syndrome of inappropriate antidiuretic hormone secretion], osteomalacia/rickets and ROHHAD [rapid onset of obesity, hypoventilation, hypothalamic dysfunction and autonomic dysregulation]); and (3) dermatologic/rheumatologic syndromes (hypertrophic osteoarthropathy and paraneoplastic pemphigus). Familiarity with these syndromes can aid in early diagnosis, treatment and imaging optimization.

Tumor-induced hypophosphatemic osteomalacia caused by a mesenchymal tumor of the mandible managed by a segmental mandibulectomy and microvascular reconstruction with a free fibula flap

BACKGROUND

Tumor-induced osteomalacia is a rare paraneoplastic syndrome in which patients develop hypophosphatemia and osteomalacia.

METHODS AND RESULTS

Here, we report a unique case of a 42-year-old man who presented to our institution with a 1-year history of pain in his ribs, hips, lower back, and feet. Radiologic examination revealed a decrease in bone density and multiple insufficiency fractures. Laboratory evaluation revealed hypophosphatemia, low serum 1,25 dihydroxy vitamin D₃ , and elevated fibroblast growth factor 23 (FGF23). A positron emission tomography/CT scan showed increased uptake in the right mandibular third molar region. Panoramic radiography and CT scanning showed a lytic expansile bone lesion. A mandibular bone biopsy revealed a mixed connective tissue tumor. A right segmental mandibulectomy was performed, followed by microvascular reconstruction. The resection was confirmed by normalization of serum phosphate and FGF23.

CONCLUSION

Successful management of this condition was achieved, with complete surgical resection of the tumor and reconstructive surgery.