Tubular phosphate transport: a comparison between different methods of urine sample collection in FGF23-dependent hypophosphatemic syndromes

OBJECTIVES

Tubular maximum phosphate reabsorption per glomerular filtration rate (TmP/GFR) is used to evaluate renal phosphate reabsorption and it is a useful tool for the differential diagnosis of hypophosphatemic syndromes. TmP/GFR is typically calculated from fasting plasma and second morning void urine samples, obtained 2 h after the first void (TmP/GFR 2 h). The purpose of this study was to evaluate if TmP/GFR calculated from 24 h urine collection (TmP/GFR 24 h) can be used as an alternative for TmP/GFR 2 h in patients with urine phosphate wasting.

METHODS

We enrolled adult patients with X-linked hypophosphatemia (XLH) or tumor-induced osteomalacia (TIO). All patients underwent blood and urine sample collections, to calculate TmP/GFR 24 h and TmP/GFR 2 h.

RESULTS

Twenty patients (17 XLH and 3 TIO), aged 24-78 years, were included. All patients had low TmP/GFR 2 h (0.35 mmol/L, IQR 0.24-0.47 mmol/L) and TmP/GFR 24 h (0.31 mmol/L, IQR 0.22-0.43 mmol/L). The concordance correlation coefficient between TmP/GFR 2 h and TmP/GFR 24 h was 0.86 (95 % CI: 0.69-0.93), with a systematic bias of 0.05 mmol/L (95 % limits of agreement: -0.10 to 0.20). Furthermore, in 70 % (i.e., 14 patients out of 20) and 80 % (i.e., 16 patients out of 20) of cases the difference between TmP/GFR 2 h and TmP/GFR 24 h was within ±30 % and ±35 %, respectively.

CONCLUSIONS

Despite TmP/GFR 2 and 24 h show a relatively suboptimal agreement, the difference between the two parameters appears to be small and not clinically significant in the setting of adult patients with FGF23-dependent urine phosphate wasting and secondary hypophosphatemia.

Tumour-induced osteomalacia: the long road to diagnosis and recovery

Tumour-induced osteomalacia is caused by tumorous production of fibroblast growth factor 23 (FGF23) leading to urinary phosphate wasting, hypophosphataemia and decreased vitamin D activation. The resulting osteomalacia presents with muscle weakness and bone pain but progresses to multiple pathological fractures. Patients often remain undiagnosed for years with severe physical, psychological and economic ramifications. A young woman presented with multiple spontaneous fractures including bilateral femoral fractures. Laboratory tests revealed severe hypophosphataemia, elevated bone turnover markers and low to normal calcium and 25-hydroxy-vitamin D levels. Treatment with phosphate, alfalcalcidol, calcium and magnesium was initiated. 68Gallium-DOTATOC positron emission tomography imaging revealed a mass in the right foot and venous sampling of FGF23 from all extremities confirmed this tumour as the culprit. Biopsy and histology were consistent with a phosphaturic mesenchymal tumour, which was surgically resected. Phosphate levels quickly normalised postoperatively but a long convalescence with hungry bone syndrome, fracture healing and physical therapy followed.

Membranous Nephropathy as a Paraneoplastic Syndrome in Cancer of Unknown Primary

BACKGROUND/AIM

Membranous nephropathy (MN) is a nephrotic syndrome with both idiopathic and secondary etiologies. The mechanism of cancer-associated MN is presumed to involve the immunological production of antibodies against a tumor antigen, although little is known about the detailed mechanism. Lung cancer is a major neoplasm associated with cancer-associated MN. However, the simultaneous occurrence of secondary MN in patients with cancer of unknown primary (CUP) remains unclear.

CASE REPORT

Here, we present a case of secondary MN in a 72-year-old female as a paraneoplastic syndrome in CUP. Thoracic radiotherapy up to a total of 60 Gy was initially performed on the right subclavian and mediastinal lymph nodes. Computed tomography revealed marked shrinking of these lymph nodes, and the secondary MN also improved without any symptoms.

CONCLUSION

The presence of proteinuria in patients with CUP suggests the possibility of secondary MN as a rare differential diagnosis.

Thymic carcinoma presenting with overlap polyarthritis and myositis: A rare paraneoplastic syndrome in childhood

Thymic tumors are very rare neoplasms in children and account for less than 1% of mediastinal tumors in pediatric patients. One-third of the pediatric patients present with symptoms related to the compression of the tumor mass on the surrounding anatomic structures, and paraneoplastic syndromes such as myasthenia gravis, pure red cell aplasia, acquired hypogammaglobulinemia, and connective tissue disorders, which rarely occur in children with thymic tumors. Herein, we report a case of thymic carcinoma mimicking the symptoms of a connective tissue disease with symmetrical polyarthritis accompanying myositis, fever, weight loss, and malaise in a 15-year-old male patient. To our knowledge, this is the first case pediatric thymic carcinoma accompany with severe polyarthritis and myopathy, thus we have reviewed the current literature regarding the cases of thymic malignancies coexisting with paraneoplastic syndromes in children.

Lung Cancer Wherein Durvalumab Induced Both Anti-CRMP-5 Antibody-related Paraneoplastic Neurological Syndromes and Neurological Adverse Events

A 68-year-old man with small-cell lung cancer developed anti-collapsin response-mediator protein (CRMP)-5 antibody-related paraneoplastic neurological syndrome (PNS) presenting with ataxia and chorea during treatment with durvalumab. As a result of steroid therapy, anti-CRMP-5 antibodies became negative, hyperintense lesions on brain magnetic resonance imaging disappeared, and neurological symptoms improved. After resuming durvalumab, he became unable to walk due to neurological adverse events (nAEs). There have been no reported cases manifesting PNSs and nAEs as a result of the same immune checkpoint inhibitors (ICIs) administered at different times. Resuming ICIs in patients diagnosed with PNSs should be performed with prudence.

Tumor-induced osteomalacia: An overview

Tumor-induced osteomalacia (TIO) is rare paraneoplastic syndrome of hypophosphatemic osteomalacia, caused by phosphaturic factors secreted by small mesenchymal origin tumors with distinct pathological features, called 'phosphaturic mesenchymal tumors'. FGF23 is the most well-characterized of the phosphaturic factors. Tumors are often small and located anywhere in the body from head to toe, which makes the localisation challenging. Functional imaging by somatostatin receptor-based PET imaging is the first line investigation, which should be followed with CT or MRI based anatomical imaging. Once localised, complete surgical excision is the treatment of choice, which brings dramatic resolution of symptoms. Medical management in the form of phosphate and active vitamin D supplements is given as a bridge to surgical management or in inoperable/non-localised patients. This review provides an overview of the epidemiology, pathophysiology, pathology, clinical features, diagnosis, and treatment of TIO, including the recent advances and directions for future research in this field.

Whole-Exome Sequencing Reveals the Genomic Profile and IL6ST Variants as a Prognostic Biomarker of Paraneoplastic Pemphigus-Associated Unicentric Castleman Disease

Unicentric Castleman disease (UCD) is a rare lymphoproliferative disorder. Paraneoplastic pemphigus (PNP) is a major complication associated with poor UCD prognosis. However, the genomic profiles and prognostic biomarkers of PNP-associated UCD remain unclear. In this study, we performed whole-exome sequencing analysis for 28 matched tumor-normal pairs and 9 tumor-only samples to define the genomic landscape of Chinese patients with PNP-associated UCD. An integrative analysis was performed to identify somatic variants, the mutational signatures, and key pathways in tumors. Besides, we analyzed the relationship among mutated genes, clinical characteristics, and prognosis. Sixty-one somatic mutant genes were identified in >1 patient with PNP-associated UCD. Specifically, IL6ST and PDGFRB were the most frequently mutated genes (32%), followed by DPP6 (18%) and MUC4 (18%). Signaling molecules and interactions, cellular processes, and signal transduction pathways were enriched. Furthermore, we found that poor overall survival was related to IL6ST variants (P = .02). Finally, we classified PNP-associated UCD into 4 genomic subgroups: IL6ST, PDGFRB, IL6ST-PDGFRB, and an unknown subgroup. In summary, we defined the molecular profile of PNP-associated UCD and identified a potential molecular biomarker for predicting prognosis, which may provide therapeutic targets for treating this severe disorder.

Clinical Characteristics of Malignant Phosphaturic Mesenchymal Tumor Causing Tumor-Induced Osteomalacia

CONTEXT

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome usually caused by oversecretion of fibroblast growth factor 23 (FGF23) from a phosphaturic mesenchymal tumor (PMT). PMTs are usually benign neoplasms but some of them show malignant characteristics.

OBJECTIVE

The aim of this study was to compare the clinical characteristics of benign and malignant PMTs inducing TIO.

METHODS

On March 31, 2023, we performed a systematic review of individual patient data analysis in Medline, Google Scholar, Google book, and Cochrane Library using the terms "tumor induced osteomalacia," "oncogenic osteomalacia," "hypophosphatemia," with no language restrictions and according to Preferred Reporting Items for Systematic reviews and Meta-Analyses criteria.

RESULTS

Overall, we collected data from 837 patients with TIO in which the diagnosis of benign and malignant PMT was specified. Of them, 89 were affected by malignant PMT and 748 by benign PMT. Patients with malignant PMTs were younger and presented bone pain, functional impairment, and bone deformities more frequently. Malignant PMTs showed higher values of intact FGF23 and a higher mortality rate.

CONCLUSION

The study results identify the clinical characteristics of patients with malignant TIO, permitting the early identification of patients with PMT at increased risk of malignancy. This may significantly improve the diagnostic approach to disease. Further experimental studies are mandatory to clarify the role of FGF23 in the pathogenesis of malignancy in PMTs.

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

BACKGROUND Phosphaturic mesenchymal tumor (PMT) is an extremely rare mesenchymal neoplasm that is commonly seen in bone and soft tissue. It is associated with a paraneoplastic syndrome, oncogenic osteomalacia, due to tumor-induced urinary phosphate wasting. It is demonstrated to be predominantly mediated by fibroblast growth factor 23 (FGF23)/fibroblast growth factor receptor 1 (FGFR1) axis. Clinically, PMT usually presents as a solitary lesion in the bone. The diagnosis of PMT is challenging due to its non-specific clinical manifestation, radiologic findings, and morphological features. CASE REPORT We report the case of a 50-year-old man presenting with multiple lytic bone lesions and associated pathologic fracture of the right femur, clinically suspicious for multiple myeloma or other metastatic malignant process. Resection from the right femur showed a hypercellular lesion composed of oval-to-spindled cells infiltrating the native trabecular bone with admixed multinucleated giant cells. Immunohistochemical (IHC) staining and in situ hybridization (ISH) demonstrated the tumor cells were positive for SATB2, ERG, FGFR1, and FGF23 ISH. DNA and RNA next-generation sequencing showed marked increases in mRNA levels of FGF23 and FGFR1. The constellation of clinicoradiologic, histomorphologic, IHC, and molecular findings supported a diagnosis of primary benign PMT. CONCLUSIONS This case report discusses a patient with PMT presenting with multifocal lesions due to tumor-induced osteomalacia at initial presentation. We hope that this report will increase the awareness of clinician and pathologists of PMT as a differential diagnosis in patients presenting with multifocal lytic bone lesions. In turn, this will prevent misdiagnosis and overtreatment of a typically benign process.

Cytological findings of phosphaturic mesenchymal tumor: Report of a case with summary of prior published cases

Phosphaturic mesenchymal tumor (PMT) is a rare neoplasm causing tumor-induced osteomalacia (TIO) and is characterized by secretion of FGF23, renal phosphate wasting and hypophosphataemia. It can be completely cured by resection and therefore its diagnosis is of utmost importance. Although the histology is well described, there is sparse literature on cytology of PMT and only three cases have been described so far. A 45-year-old lady presented with a non-tender mass in hard palate for 2 years from which fine-needle aspiration was done. The smears were paucicellular and showed bland spindle cells embedded in osteoid-like stromal matrix in a hemorrhagic background. Here we take the opportunity to describe the cytological findings of PMT along with its cytological differentials and a summary of prior published cases.

Paraneoplastic Dermatoses and Cutaneous Metastases

Paraneoplastic syndromes include a variety of cutaneous presentations that have an associated internal malignancy. Some syndromes have a strong correlation to specific internal malignancies, whereas others are associated with a multitude of tumors. There are many cutaneous manifestations that suggest hematologic disorders, which will be reviewed in detail. Cutaneous metastases are commonly from breast and lung cancers and can present as nodules, vascular lesions, eczematous dermatitis, or inflammatory lesions. The most common histologic presentation of cutaneous metastasis is that of a dermal-based or subcutaneous-based nodule with sparing of the epidermis. Determination of origin of tumor requires immunohistochemistry and clinical correlation.

Risk factors and prognosis of malignant peritoneal mesothelioma with paraneoplastic syndrome

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is a rare and highly aggressive tumor. Its clinical manifestations are diverse, and the symptoms are not specific. Some patients will develop paraneoplastic syndrome (PS) during the disease course. This study aims to analyze the risk factors of PS in patients with MPM and their impacts on prognosis.

METHODS

The clinical data of MPM patients who underwent cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) at our center from June 2015 to May 2023 were retrospectively analyzed. MPM patients were divided into PS group and non-PS group according to the diagnostic criteria. Univariate and multivariate analyses were performed to explore the risk factors of PS in MPM patients, and to analyze the impact of PS on prognosis.

RESULTS

There were 146 MPM patients in this study, including 60 patients (41.1%) with PS and 86 patients (58.9%) without PS. The highest incidence of PS was thrombocytosis (33.6%), followed by neoplastic fever (9.6%). Univariate analysis revealed 8 factors (P < 0.05) with statistically significant differences between the two groups: prior surgical scores, targeted therapy history, Karnofsky performance status score, preoperative carbohydrate antigen (CA) 125 level, vascular tumor embolus, peritoneal cancer index, completeness of cytoreduction (CC) score and intraoperative ascites. Multivariate analysis identified 3 independent factors associated with PS: preoperative CA 125 level, vascular tumor embolus, and CC score. Survival analysis demonstrated that MPM patients with PS had worse prognosis, although PS was not an independent prognostic factor.

CONCLUSIONS

PS is not rare in patients with MPM, and is independently associated with preoperative CA 125 level, vascular tumor embolus and CC score. PS often indicates advanced disease and poor prognosis.

Clinical Features of Cutaneous Paraneoplastic Syndromes in Hodgkin Lymphoma

Cutaneous paraneoplastic syndromes due to Hodgkin lymphoma present with a wide spectrum of clinical manifestations from generalized pruritus to exfoliative erythroderma. We summarize the clinical findings and outcomes of 14 patients with Hodgkin lymphoma and associated cutaneous paraneoplastic syndromes treated at Mayo Clinic over the past 3 decades. Cutaneous paraneoplastic syndromes may be present at the time of lymphoma diagnosis, whereas in other patients, it may appear at the time of relapse, including patients with initial absence of cutaneous manifestations during the initial lymphoma presentation. Our results indicate that complete resolution of the paraneoplastic syndrome is associated with significantly improved overall survival. Recognition of cutaneous paraneoplastic syndromes is a crucial surrogate of relapsed malignancy and treatment requires targeting the underlying malignancy.

[Bazex syndrome: a rare paraneoplastic disease]

Bazex syndrome is a paraneoplastic disorder most commonly linked to squamous cell carcinomas of the upper aerodigestive tract, followed by lung cancer and other malignancies. It manifests through three stages of skin involvement that mirror the tumor's progression. Remarkably, skin lesions precede tumor symptoms or diagnosis in two-thirds of cases, underscoring the crucial role of suspecting this condition as it can promptly reveal an underlying neoplasm. Treatment primarily focuses on addressing the root neoplasm, with recurrent skin lesions potentially indicating tumor relapse. In this context, we present a clinical case involving a male patient whose manifestation of this syndrome facilitated the timely diagnosis of lung adenocarcinoma. This case underscores the significance of understanding this uncommon syndrome and its link to cancer, enabling early and accurate oncological diagnosis.

Digital Gangrene as a Paraneoplastic Manifestation of Peripheral T-cell Lymphoma Not Otherwise Specified Type

BACKGROUND

Peripheral T cell lymphoma (PTCL), not otherwise specified (NOS) is a heterogenous group of predominantly nodal T cell lymphomas that generally presents with lymphadenopathy with or without extra nodal involvement. Acral vascular syndrome clinically presents as digital ischemia with Raynaud's phenomenon and acral cyanosis. Although, this condition is commonly associated with connective tissue disorder, smoking and vasculitis, its association with lymphoid malignancy is very rare. Here, we present a case report of a patient with digital gangrene of all toes and fingers as a presenting symptom of PTCL-NOS.

CASE DESCRIPTION

A 62 year old male presented with digital ischemia associated with pain, low grade fever, loss of appetite and significant weight loss of 6 kilograms over a period of 3 months. On examination, he was found to have bilateral inguinal and axillary lymph nodes with gangrenous changes over toes and fingers but peripheral pulses were palpable. On evaluation he had anemia, elevated ESR and CRP. CT angiogram revealed thinned out digital arteries with multifocal areas of narrowing. Patient was screened for other causes of digital gangrene and was tested negative for ANCA, ANA, cryoglobulins and viral markers. Lymph node biopsy with IHC was suggestive of peripheral T-cell lymphoma-NOS and was started on CHOP regimen. Lymph nodes size decreased and gangrenous changes resolved.

CONCLUSION

Though digital ischemia is a rare paraneoplastic presentation of lymphoma, it should be considered if there is a rapid progression of gangrene. Early initiation of chemotherapy may result in the reduction of further progression of digital gangrene and thus prevent permanent disability. In our patient, progression of gangrene was prevented even though it was an aggressive variant of T cell lymphoma.

Management of Paraneoplastic Syndromes in the Era of Immune Checkpoint Inhibitors

OPINION STATEMENT

Our understanding of paraneoplastic neurologic syndromes (PNS) has blossomed over the past few decades. Clinicians have access to more robust diagnostic criteria and have a heightened index of suspicion for these disorders. Nonetheless, treatment, which typically includes immunosuppression, and response to treatment, varies. Due to persistent difficulty in making a definitive diagnosis, we favor empiric treatment when a possible diagnosis of PNS is suspected, and other alternative causes have substantially been excluded (e.g., infections, toxic-metabolic derangements, metastasis, or leptomeningeal disease). Treatment of the underlying cancer, if identified, is the first therapeutic step and can prevent disease worsening and in rare cases, can reverse neurologic symptoms. In addition to anti-cancer treatment, first line immunotherapies, which include corticosteroids, intravenous immunoglobulins (IVIG), or plasma exchange (PLEX) are typically used. If partial or no benefit is seen, second line immunotherapeutic agents such as rituximab are considered. Additionally, the severity of the initial presentation and possible risk for relapse influences the use of the latter agents. Symptomatic management is also an important component in our practice and will depend on the syndrome being treated. One of the more novel entities we are facing currently is the management of immune checkpoint (ICI)-induced PNS. In those cases, current American Society of Clinical Oncology (ASCO) guidelines are followed.

Atezolizumab-induced cerebellar ataxia in a patient with metastatic small cell lung cancer: A case report and literature review

INTRODUCTION

The use of immune checkpoint inhibitors, which have an important role in the treatment of malignant tumors, is increasing. Although rarely observed, neurological immune-related adverse events associated with immune checkpoint inhibitors result in high morbidity and mortality. Small cell lung cancer is a common cause of neurological paraneoplastic syndromes. The differentiation between paraneoplastic syndromes and neurological immune-related adverse events is important in patients using immune checkpoint inhibitors. Cerebellar ataxia caused by atezolizumab is a rare immune-related adverse event.

CASE REPORT

In this context, we present a 66-year-old man with small cell lung cancer who developed immune-mediated cerebellar ataxia after three cycles of atezolizumab, a programmed cell death ligand-1 inhibitor. The admission of brain and spinal gadolinium-based contrast-enhanced magnetic resonance imaging supported the preliminary diagnosis and indicated leptomeningeal involvement. However, the blood tests and a lumbar puncture did not reveal any structural, biochemical, paraneoplastic, or infectious cause.

MANAGEMENT AND OUTCOME

High-dose steroid treatment resulted in an improvement in the radiological involvement, as evidenced both clinically and on follow-up whole spine magnetic resonance imaging. Therefore, the immunotherapy was discontinued. The patient was discharged on day 20 without neurological sequelae.

DISCUSSION

In light of this, we present this case to emphasize the differential diagnosis of neurological immune-related adverse events originating from immune checkpoint inhibitors, which require rapid diagnosis and treatment, and clinically similar paraneoplastic syndromes and radiologically similar leptomeningeal involvement, in a case of small cell lung cancer.

Advances of autoimmune rheumatic diseases related to malignant tumors

BACKGROUND

Malignant neoplasms are a well-recognized global public health concern, with significant impacts on human health and quality of life. The interplay between tumors and autoimmune rheumatic diseases is complex, and the resulting tumor-associated rheumatic diseases represent a rare and intricate group of conditions that occur in the context of malignant tumors. In addition, various rheumatic diseases can arise as a consequence of oncology treatment. These diseases present with intricate clinical manifestations and pathological features, often rendering them challenging to diagnose and impacting patients' quality of life. Despite this, they have yet to be fully recognized.

METHODS

This article presents a literature review of published original articles and review articles concerning paraneoplastic rheumatic syndromes and rheumatic diseases associated with cancer treatment. We conducted a comprehensive literature search in PubMed, Web of Science and Google Scholar databases, excluding duplicated and irrelevant studies. In cases of duplicated research, we selected articles with higher impact factors for the review.

RESULTS

This review focuses on the clinical features, diagnosis, and treatment of paraneoplastic rheumatic diseases, as well as the pathogenesis of these diseases. Additionally, we summarize the autoimmune rheumatic diseases associated with cancer treatment. Ultimately, the goal of this review is to enhance recognition and improve the management of autoimmune rheumatic diseases related to tumors.

Diagnosis and management of tumor-induced osteomalacia: a single center experience

PURPOSE

The aim of this study is to review the clinical and laboratory characteristics, diagnostic and treatment modalities of tumor-induced osteomalacia (TIO) cases managed in a single center.

MATERIAL METHODS

Demographic and clinical features, biochemical findings, diagnostic procedures, treatment modalities, and outcomes of nine patients who had the diagnosis of TIO were reviewed retrospectively.

RESULTS

Mean age of the study group (F/M: 4/5) was 45.8 ± 10.8 years, and mean time from the onset of symptoms to diagnosis was 4.7 ± 2.8 years. The clinical manifestations were muscle weakness and difficulty in walking (8/9), hip pain (3/9), multiple fractures (2/9), stress fracture (2/9). Mean plasma phosphorus concentration was 1.28 ± 0.4 mg/dl at presentation. We performed radionuclide imaging modalities (18F-FDG PET/CT, Ga68-DOTATATE PET/CT, octreotide scintigraphy) in seven of nine patients, and tumor was detected in all. Lower extremity (n = 6; %67), head region (n = 2; %22) and thorax (n = 1; %11) were the tumor locations of our cases. Eight patients underwent surgery and remission was achieved postoperatively in all of the operated patients and plasma phosphorus level normalized in 4 ± 2 days. Pathological examination revealed mesenchymal tumors with different subtypes. Recurrence occurred in three patients at 13 ± 10.5 months after the first surgery. Two patients were reoperated and radiotherapy was also performed in one of them.

CONCLUSION

Hypophosphatemia necessitates careful evaluation for the etiology. TIO is one of the important causes of adult-onset hypophosphatemic osteomalacia. Diagnosis of TIO is essential because the laboratory and clinical findings resolve after appropriate treatment.

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.

Tumor-Induced Osteomalacia in Patients With Malignancy: A Meta-analysis and Systematic Review of Case Reports

CONTEXT

Tumor-induced osteomalacia (TIO) due to fibroblast growth factor 23 (FGF23) overexpression is becoming recognized in patients with malignancy. The condition may be underdiagnosed, with a scarce medical literature.

OBJECTIVE

To perform a meta-analysis of case reports to allow a better understanding of malignant TIO and its clinical implications.

METHODS

Full texts were selected according to strict inclusion criteria. All case reports were included where patients had hypophosphatemia, malignant TIO, and FGF23 blood levels. Thirty-two of 275 eligible studies (n = 34 patients) met inclusion criteria. A list of desired data was extracted and graded for methodological quality.

RESULTS

Prostate adenocarcinoma (n = 9) were the most tumors reported. Twenty-five of 34 patients had a metastatic disease and a poor clinical outcome was reported for 15 of 28 patients. The median levels of blood phosphate and C-terminal FGF23 (cFGF23) were 0.40 mmol/L and 788.5 RU/mL, respectively. For most of patients, blood PTH was elevated or within range, and calcitriol levels were inappropriately low or normal. Alkaline phosphatase concentrations were increased for 20 of 22 patients. The cFGF23 values were significantly higher for patients with a poor clinical outcome when compared to other patients (1685 vs 357.5 RU/mL). In case of prostate cancer, cFGF23 levels were significantly lower (429.4 RU/mL) than for other malignancies (1007.5 RU/mL).

CONCLUSION

We report for the first time a detailed description of the clinical and biological characteristics of malignant TIO. In this context, FGF23 blood measurement would be of value for the diagnostic workup, prognostication, and follow-up of patients.

Seronegative paraneoplastic encephalomyelitis in occult colonic carcinoma

Paraneoplastic neurological syndromes are immune-mediated neurological attacks triggered by malignancies. They are commonly associated with lung, breast, thymus, gynaecological and haematological malignancies. We report a case of a male patient in his late 40s with paraneoplastic encephalomyelitis due to a colonic adenocarcinoma emphasising a low threshold for extensive cancer evaluation in all subacutely presenting neurological syndromes. We also emphasise that the absence of a positive onconeural antibody does not preclude the diagnosis of a paraneoplastic syndrome.

Paraneoplastic pemphigus misdiagnosed as juvenile dermatomyositis: A case report

Paraneoplastic pemphigus (PNP) is a rare autoimmune skin disease closely related to tumors, characterized by a maculopapular rash with mucosal pain, bronchiole occlusion, and respiratory failure may occur over time, even resulting in death. We report a rare case of a child with autoimmune PNP misdiagnosed as juvenile dermatomyositis (JDM), and summarize the key points of differentiation of clinical manifestations and auxiliary examinations of PNP and JDM. When the diagnosis is not clear because the patient has features not typical of JDM, then skin biopsy and other diagnostic studies should be considered prior to any immunosuppressive therapy, as this could potentially obscure and delay the diagnosis of malignancy.

Presence of Gastrointestinal Paraneoplastic Syndrome at Diagnosis in Dogs With Cutaneous Mast Cell Tumors and Its Influence on Disease-Free Interval and Survival

Paraneoplastic syndrome (PNS) is a combination of signs unrelated to the physical presence of a tumor and/or its metastases. Its presence may result in poorer clinical outcomes and prognosis. Gastrointestinal ulceration is a well-known PNS in animals with cutaneous MCT. This retrospective study analyzed the occurrence of gastrointestinal (GI) PNS at the time of diagnosis. Using medical records, we attempted to correlate the occurrence of these GI signs with clinical and histologic criteria, as well as to evaluate their influence on the disease-free interval (DFI) and survival (ST) over a 6-year follow-up period (2013-2020). The medical records of 41 dogs with a confirmed diagnosis of cutaneous MCT treated between 2013 and 2014 were included. All dogs underwent surgical biopsy or tumor excision, endoscopic and histologic examination to evaluate possible GI lesions. The presence and severity of GI signs were recorded. Clinical data such as the history of recurrence, number of tumors, tumor size, presence of ulceration, local pruritus, edema and erythema, histopathological classification, and mitotic index were extracted from medical records. Clinical signs relating to the GI system were observed in 41.5% of the dogs and were classified as mild in 94.1% at the time of diagnosis. Endoscopic examination of the upper digestive tract showed evidence of inflammation, but histologic examination of the mucosa showed no serious lesions in any case. There was no significant association between the occurrence of clinical GI signs and any of the variables studied. Follow-up issues meant that only 38 dogs were included for evaluation of the ST and 32 for DFI analysis. DFI was 25.1 months for dogs with GI signs and 14.8 months for dogs without GI signs. At the end of the study, 71.1% of patients had died. Survival time for dogs with GI signs was 54.9 months and 48 months for dogs without GI signs. Over the 6 years of the study, no differences were observed between the ST and the DFI, and the presence or absence of GI PNS at the time of diagnosis.

Incidence and clinical relevance of paraneoplastic syndromes in patients with renal cell carcinoma

BACKGROUND

Paraneoplastic syndromes (PNS) are defined as the signs and symptoms attributed to cytokines or hormones released from a tumor or a patient's immune system. PNS have been reported with many cancers for decades and data supporting their relevance in renal cell carcinoma (RCC) are largely historical. The widespread use of electronic medical record (EMR) systems provides a more robust method to capture data. The objective of this study was to establish contemporary data regarding the incidence and relevance of PNS in patients undergoing nephrectomy for suspected RCC.

METHODS

In this retrospective single-institution study, 851 patients undergoing nephrectomy for suspected RCC between 2011 and 2018 were assessed for the presence or absence of PNS as defined by laboratory abnormalities. Factors associated with PNS and with all-cause mortality were examined.

RESULTS

The incidence of PNS was 33.1% among 851 patients prior to nephrectomy. The most prevalent PNS were anemia (22.4%), thrombocytosis (7.5%), and elevated C-reactive protein (CRP) (7.4%). PNS were more common in women (39.2% vs. 29.4%, p = 0.0032) and higher stage RCC (31.1% of stage I vs. 54.2% of stage IV, p = 0.0036). Factors associated with the presence of PNS in multivariable analysis included female gender, high comorbidity, and stage IV RCC. Prenephrectomy PNS were associated with poorer survival in multivariable analysis (HR: 2.12, p = 0.0002). Resolution of PNS occurred in 52.1% of patients after nephrectomy, including 55.2% with stage I to III and 38.5% with stage IV RCC (p = 0.10).

CONCLUSIONS

Using EMR data, laboratory evidence of PNS was present in one-third of a contemporary cohort of patients undergoing nephrectomy, with >50% of PNS resolving after surgery. Consistent with prior reports, PNS are more common in higher-stage RCC and are associated with poorer survival in RCC patients.

The Leser-Trélat Sign in a Patient with Gastric Adenocarcinoma

Dear Editor, The Leser-Trélat sign is a rare paraneoplastic cutaneous marker of internal malignancy characterized by sudden eruption of multiple seborrheic keratoses (SK). It is mostly associated with gastrointestinal adenocarcinomas (gastric, colon, rectal), and less frequently with breast cancer and lymphoproliferative disorders/lymphoma (1). It can be also associated with lung, kidney, liver, and pancreas malignancy (1). Pruritus occurs in half of the patients. Lesions rarely require any treatment, as they mostly tend to resolve once management of the underlying malignancy has started (2). A 32-year-old female patient with family history of colorectal cancer presented with an acute eruption of SK. She reported that the first symptoms were the loss of appetite and intense pruritus. The brown papules appeared over a period of 2-3 months, first on her back, then on the abdomen, thorax, neck, and lasty on the extremities (Figures 1a and b.). Physical examination showed numerous brown hyperkeratotic papules and plaques on the trunk, neck, and extremities. The patient complained of night sweating, epigastric pain, and heartburn. Over the last three months, she had lost over 15 kg. The patient had experienced an episode of acute gastritis 10 years ago and had been treated for Helicobacter pylori infection 4 years ago. Laboratory results showed elevated sedimentation rate and decreased levels of hemoglobin, erythrocytes, and hematocrit. CA-19-9 and CEA levels were elevated. Gastroscopy with multiple biopsies confirmed gastric adenocarcinoma. An abdominal CT scan revealed enlarged retroperitoneal lymph nodes. SK withdrew after total gastrectomy and commencement of chemotherapy. The Leser-Thrélat sign was named after two surgeons, Edmund Leser and Ulysse Trélat, who described the eruption of cutaneous lesions in patients with cancer (3). However, the correlation between multiple SK and internal malignancy was described by Hollander in 1900 (4). Acute eruption of SK has also been reported in some other cases, such as benign tumors, pregnancy, human immunodeficiency virus infections, use of adalimumab, and others, which indicates that the Leser-Trélat sign is not highly specific (5). It is also somewhat controversial whether a sudden appearance of SK can be considered a marker for internal malignancy, since both SK and malignancies occur more frequently in the elderly population, thus allowing for a higher likelihood of coincidence (6). However, the patient in this case was young and therefore less likely to suddenly develop such a large number of SK, which are more commonly seen after the age of 50 (7). Although the pathogenesis of Leser-Thrélat sign is not fully understood, there are data suggesting an association with tumor-secreting growth factors including epidermal growth factor and transforming growth factor-alpha, both of which can stimulate the epidermal growth factor receptor (8). Sudden appearance of eruptive SK is uncommon in young patients. This specific sign highlights the importance of considering internal malignancy in the differential diagnosis of patients presenting with eruptive SK.

A Case Series of Nephrotic Syndrome: A Harbinger of Catastrophic Oncologic Diseases

INTRODUCTION

A cancer patient can have numerous complications involving the kidneys, ranging from acute kidney injury, chronic kidney disease, glomerulopathies, electrolyte, and acid-base disorders. It can be due to the malignancy itself or due to chemotherapeutic agents. Paraneoplastic glomerulopathy is a rare presentation of neoplastic disease.

CASE DISCUSSION

We present a case series of two patients presenting with nephrotic syndrome as a paraneoplastic syndrome associated with a gynecologic tumor. Both patients responded only partially to steroids and immunosuppressive therapy. Complete remission was only achieved after treatment of primary malignancy.

CONCLUSION

It is critical to recognize this entity as immunosuppression may induce a flare in the tumor course and worsen outcomes. So, age-appropriate screening of malignancy should ideally be performed in any adult patient with nephrotic syndrome.

[Lichenoid drug eruption with unfavorable evolution. Difficulties in diagnosis]

We report the case of a woman who started with a lichenoid eruption, unfavorable evolution, for which a drug reaction was suspected. The final diagnosis was paraneoplastic pemphigus. Multidisciplinary care and evaluation by an Allergist is important in patients with severe skin reactions, suspected of drug reactions, due to the difficulty in establishing the diagnosis.

S2k guidelines on the management of paraneoplastic pemphigus/paraneoplastic autoimmune multiorgan syndrome initiated by the European Academy of Dermatology and Venereology (EADV)

BACKGROUND

Paraneoplastic pemphigus (PNP), also called paraneoplastic autoimmune multiorgan syndrome (PAMS), is a rare autoimmune disease with mucocutaneous and multi-organ involvement. PNP/PAMS is typically associated with lymphoproliferative or haematological malignancies, and less frequently with solid malignancies. The mortality rate of PNP/PAMS is elevated owing to the increased risk of severe infections and disease-associated complications, such as bronchiolitis obliterans.

OBJECTIVES

These guidelines summarize evidence-based and expert-based recommendations (S2k level) for the clinical characterization, diagnosis and management of PNP/PAMS. They have been initiated by the Task Force Autoimmune Blistering Diseases of the European Academy of Dermatology and Venereology with the contribution of physicians from all relevant disciplines. The degree of consent among all task force members was included.

RESULTS

Chronic severe mucositis and polymorphic skin lesions are clue clinical characteristics of PNP/PAMS. A complete assessment of the patient with suspected PNP/PAMS, requiring histopathological study and immunopathological investigations, including direct and indirect immunofluorescence, ELISA and, where available, immunoblotting/immunoprecipitation, is recommended to achieve a diagnosis of PNP/PAMS. Detection of anti-envoplakin antibodies and/or circulating antibodies binding to the rat bladder epithelium at indirect immunofluorescence is the most specific tool for the diagnosis of PNP/PAMS in a patient with compatible clinical and anamnestic features. Treatment of PNP/PAMS is highly challenging. Systemic steroids up to 1.5 mg/kg/day are recommended as first-line option. Rituximab is also recommended in patients with PNP/PAMS secondary to lymphoproliferative conditions but might also be considered in cases of PNP/PAMS associated with solid tumours. A multidisciplinary approach involving pneumologists, ophthalmologists and onco-haematologists is recommended for optimal management of the patients.

CONCLUSIONS

These are the first European guidelines for the diagnosis and management of PNP/PAMS. Diagnostic criteria and therapeutic recommendations will require further validation by prospective studies.

Annular and acral/facial dyskeratotic paraneoplastic disorders

Annular and acral/facial dyskeratotic paraneoplastic disorders are inflammatory dermatoses that occur in association with distant cancers but are not precursors, extensions, or metastases of them. There are four classical entities under this rubric: two gyrate entities, erythema annulare centrifugum and erythema gyratum repens, and two acral/facial dyskeratotic entities, acrokeratosis paraneoplastic (Bazex syndrome) and tripe palms. Each of these entities may also occur in association with another etiopathogenesis and may present either as a classical entity or as a barely recognizable disease. We discuss these entities, their associated causes, and their differential diagnoses in turn.

Cutaneous Paraneoplastic Syndrome Affecting the Hand in a Case of Underlying Waldenström Macroglobulinemia

Paraneoplastic syndromes represent the body's immune response to an underlying malignancy. The autoimmune response to cancer can manifest itself in multiple ways, including swelling, thickening, and changes in the hand. We report the case of a 65-year-old man who presented with hand swelling that was initially attributed to a work-related finger laceration. The patient developed edema and stiffness in the hand, which was subsequently diagnosed as Waldenström macroglobulinemia. Hand surgeons should be aware that atypical hand and wrist symptoms should raise the suspicion for the potential of a paraneoplastic syndrome and an underlying malignancy.

Case report: Amphiphysin-IgG autoimmunity: a paraneoplastic presentation of appendiceal goblet cell carcinoma

Background

Appendiceal goblet cell carcinoma (aGCC) is a rare neoplasm with mixed endocrine and exocrine features. No paraneoplastic neurological syndromes or autoantibodies have been identified in cases of aGCC or even appendiceal tumors. Amphiphysin-immunoglobulin G (IgG) autoimmunity was first described in stiff-person syndrome with breast cancer. We firstly described the clinical course and pathological findings of a patient with aGCC-associated amphiphysin-IgG autoimmunity.

Case presentation

A 54-year-old man who developed aGCC was admitted for acute disturbance of consciousness, psychiatric symptoms, cognitive impairment, seizure and hypotension. Amphiphysin-IgG was detected in the patient's serum and CSF by immunoblotting and tissue-based indirect immunofluorescence assay confirming the diagnosis of definite paraneoplastic amphiphysin-IgG-positive encephalitis. Histopathology revealed amphiphysin protein expression and accompanying immune cell infiltration (predominantly CD20+ B cells, CD3+ and CD8+ T cells) within the tumor tissue, suggesting a possible paraneoplastic origin of amphiphysin-associated paraneoplastic neurological syndromes (PNSs) in this case. Although the patient's symptoms resolved after high-dose corticosteroid therapy, he experienced recurrence 6 months later, manifesting as paraneoplastic cerebellar dysfunction. Despite treatment with IV cyclophosphamide and oral mycophenolate mofetil, no improvement was noted.

Conclusions

This case suggests that aGCC may trigger amphiphysin-IgG autoimmunity.

Paraneoplastic syndrome due to angiomatoid fibrous histiocytoma: a known presentation of an uncommon diagnosis in a rare site and age

A woman in her 70s presented with a small subcutaneous retrosacrococcygeal mass and a history of elevated erythrocyte sedimentation rate present for several years. It was misdiagnosed as an inflammatory process of unclear origin. She underwent further investigation with the appearance of weight loss and weakness. A sacrococcygeal mass was noted on CT scan. A core needle biopsy was inconclusive for chordoma versus myoepithelioma. Wide surgical resection of the tumour including the coccygeal bone was performed. Following surgery, all the systemic symptoms resolved with normalisation of inflammatory markers. The pathological examination showed a relatively circumscribed multinodular myxoid tumour with lymphatic tissue cuff. Pan-sarcoma fusion analysis detected an EWSR1 (Exon7)-CREB1 (Exon7) fusion gene. The lesion was diagnosed as angiomatoid fibrous histiocytoma with paraneoplastic syndrome presentation of several years' duration.

Tumour-induced osteomalacia due to residual benign glomangioma

Tumour-induced osteomalacia (TIO) is a rare paraneoplastic syndrome. The constellation of findings of unprovoked fractures, hypophosphataemia, urinary phosphate wasting and a negative genetic evaluation suggest a TIO diagnosis. Tumours leading to TIO are often small and difficult to localise using standard imaging studies. The 68Ga-DOTATATE CT/positron emission tomography, a somatostatin receptor imaging modality, is the radiographical study of choice for localisation. It is highly sensitive and specific since tumours that cause oncogenic osteomalacia have been shown to express somatostatin receptors. Complete surgical resection is the treatment of choice; however, it may not always be feasible. Burosumab, a human anti-fibroblast growth factor-23 monoclonal antibody, is a therapeutic option in cases of unresectable TIO to normalise phosphorus levels and improve fracture healing. Our patient was initiated on burosumab, which led to healing of his fractures and profound symptomatic improvement of his pain. TIO is often undiagnosed for many years, leading to significant patient morbidity.

Tumour-induced osteomalacia due to a durally-based intracranial phosphaturic mesenchymal tumour

A man in his 40s was referred with persistent hypophosphataemia and bony pain. A serum fibroblast growth factor 23 level was markedly elevated and a diagnosis of tumour-induced osteomalacia was considered. Whole body imaging revealed multiple insufficiency fractures but no osseus tumours. There was, however, a durally-based intracranial lesion whose imaging characteristics were consistent with a meningioma. The tumour was removed, leading to rapid normalisation of the patient's symptoms and serum markers. Histology confirmed a phosphaturic mesenchymal tumour. We review the literature regarding this rare clinical situation.

[Diagnostics and treatment of clinically relevant paraneoplastic syndromes]

Paraneoplastic syndromes (PS) are rare disorders with often complex clinical manifestations that occur in association with a tumor without being triggered by direct tumor invasion or compression. They arise from tumor secretions of hormones, peptides or cytokines or from immune cross-reactivity between malignant and healthy tissue. They are categorized into endocrine, neurological, dermatological, rheumatological, and hematological PS. The PS most commonly occurs in small cell lung carcinoma but also in association with other respiratory tract tumors, gynecological tumors, and hematological malignancies. The PS can precede a tumor diagnosis, therefore timely diagnosis can improve the prognosis of a malignant disease. The diagnostics are based on the clinical presentation as well as diagnostic methods depending on the underlying pathogenesis. The most important treatment approach involves the best possible treatment of the tumor and a targeted treatment is only sometimes possible. This review focuses on the clinically most frequently encountered PS.

Tumor-Induced Osteomalacia: A Systematic Clinical Review of 895 Cases

Tumor-induced osteomalacia (TIO) is a rare and largely underdiagnosed paraneoplastic condition. Previous reviews often reported incomplete data on clinical aspects, diagnosis or prognosis. The aim of this study was to present a systematic clinical review of all published cases of TIO. A search was conducted in Pubmed, Embase, Web of Science from inception until April 23rd, 2020. We selected case reports and case series of patients diagnosed with TIO, with information on tumor localization and serum phosphate concentration. Two reviewers independently extracted data on biochemical and clinical characteristics including bone involvement, tumor localization and treatment. 468 articles with 895 unique TIO cases were included. Median age was 46 years (range 9 months-90 years) and 58.3% were males. Hypophosphatemia and inappropriately low or normal 1,25-dihydroxyvitamin D levels, characteristic for TIO, were present in 98% of cases. Median tumor size was 2.7 cm (range 0.5 to 25.0 cm). Serum fibroblast growth factor 23 was related to tumor size (r = 0.344, P < 0.001). In 32% of the cases the tumor was detected by physical examination. Data on bone phenotype confirmed skeletal involvement: 62% of cases with BMD data had a T-score of the lumbar spine ≤ - 2.5 (n = 61/99) and a fracture was reported in at least 39% of all cases (n = 346/895). Diagnostic delay was longer than 2 years in more than 80% of cases. 10% were reported to be malignant at histology. In conclusion, TIO is a debilitating disease characterized by a long diagnostic delay leading to metabolic disturbances and skeletal impairment. Increasing awareness of TIO should decrease its diagnostic delay and the clinical consequences.

Palmar Fasciitis and Polyarthritis Syndrome Associated with Lung Adenocarcinoma

Palmar fasciitis and polyarthritis syndrome (PFPAS) is a rare paraneoplastic rheumatic disease with characteristic features. We herein report a 77-year-old man with lung adenocarcinoma and contralateral pulmonary metastasis receiving chemotherapy who presented with progressive symmetrical flexion contractures associated with palmar fascial thickening and arthritis of both hands and shoulders. He was diagnosed with PFPAS as paraneoplastic manifestations. Salazosulfapyridine was not effective, but 15 mg/day of oral prednisolone improved his symptoms. Physicians should consider PFPAS and rule out malignancy in patients with arthritis in the extremities and flexion contractures associated with palmar fascial thickening.

Paraneoplastic syndrome in neuroophthalmology

Paraneoplastic syndrome is a group of clinical symptoms that occur in the state of systemic malignant tumors. Paraneoplastic syndrome of the nervous system can affect any part of the central and peripheral nervous system and may also affect the eyes. In neuroophthalmology, paraneoplastic syndrome has a variety of manifestations that can affect both the afferent and efferent visual systems. The afferent system may involve the optic nerve, retina and uvea; the efferent system may involve eye movement, neuromuscular joints or involuntary eye movements and pupil abnormalities and may also have other neurological symptoms outside the visual system. This article discusses the clinical manifestations, pathological mechanisms, detection methods and treatment methods of paraneoplastic syndrome in neuroophthalmology. The performance of paraneoplastic syndrome is diverse, the diagnosis is difficult, and the treatment should be considered systematically. Differential diagnosis, optimal evaluation and management of these manifestations is not only the key to treatment but also a challenge.