Feline osteochondromatosis in a 12-year-old feline leukaemia virus-negative cat.

Feline osteochondromatosis is a spontaneous osteocartilaginous exostosis associated with feline leukaemia virus (FeLV) infection or due to a frameshift variant in the exostosin glycosyltransferase 1 (EXT1) gene. Osteochondromatosis was diagnosed in an indoor-only, 12-year-old, neutered female, Russian Blue cat. Radiographs revealed bilateral calcified proliferations in the elbow, costochondral and sternochondral joints, which distorted the normal skeletal structure. Grossly, the proliferated joints presented with consistent, rounded masses, causing complete ankylosis. The main histopathological finding was an osteocartilaginous proliferation composed of multiple irregular islands of well-differentiated hyaline cartilage surrounded and delimited by osteoid tissue. Immunohistochemistry of the osteochondromas, bone marrow and mediastinal lymph nodes, using a primary anti-FeLV gp70 antibody, and FeLV proviral DNA real-time polymerase chain reaction on bone marrow were negative. Sequencing of exon 6 of the EXT1 gene was performed and nucleotide BLAST analysis demonstrated the absence of a frameshift variant. This study reports the only case of spontaneous feline osteochondromatosis in an animal more than 10 years old.

Sacroiliac joint involvement in osteochondromatosis: identifying its prevalence and characteristics from cross-sectional imaging

PURPOSE: Apart from a few case reports, sacroiliac joint (SIJ) involvement in osteochondromatosis has not been studied. We aimed to determine the prevalence and characteristics of such involvement using cross-sectional imaging. METHODS: In this retrospective study, three observers (one junior radiologist and two musculoskeletal radiologists) independently reviewed computed tomography (CT) or magnetic resonance imaging (MRI) of patients in our database who had osteochondromatosis (≥2 osteochondromas across the skeleton) for SIJ involvement. The final decision was reached by the consensus of the two musculoskeletal radiologists in a later joint session. RESULTS: Of the 36 patients with osteochondromatosis in our database, 22 (61%) had cross-sectional imaging covering SIJs (14 females, 8 males; age range 7-66 years; mean age 23 years; 13 MRI, 9 CT). Of these, 16 (73%) had intra-articular osteochondromas. For identifying SIJ osteochondromas on cross-sectional imaging, interobserver agreement was substantial [κ = 0.67; 95% confidence interval (CI): 0.34, 1.00] between the musculoskeletal radiologists and moderate (κ = 0.59; 95% CI: 0.23, 0.94) between the junior radiologist and the final consensus decision of the two musculoskeletal radiologists. In the cohort with cross-sectional imaging, the anatomical variations of the accessory SIJ (n = 6, 27%) and iliosacral complex (n = 2, 9%) were identified in six different patients with (n = 2) and without (n = 4) sacroiliac osteochondromas. CONCLUSION: Cross-sectional imaging shows frequent (73%) SIJ involvement in osteochondromatosis, which, although a rare disorder, nevertheless needs to be considered in the differential diagnosis of such SIJ anatomical variants as the accessory SIJ and iliosacral complex. Differentiating these variants from osteochondromas is challenging in patients with osteochondromatosis.

A frameshift variant in the EXT1 gene in a feline leukemia virus-negative cat with osteochondromatosis.

Osteochondromatosis is a benign proliferative disorder characterized by cartilage-capped bony protuberances. In humans and most mammals, variants in the EXT1 or EXT2 gene are strongly correlated with the etiology of osteochondromatosis. However, in cats, osteochondromatosis has only been associated with feline leukemia virus infection. In this study, to explore other factors involved in the etiology of feline osteochondromatosis, we examined the EXT1 and EXT2 genes in a feline leukemia virus-negative cat with osteochondromatosis. Genetic analysis revealed a heterozygous single base pair duplication in exon 6 of the EXT1 gene (XM_023248762.2:c.1468dupC), leading to a premature stop codon in the EXT1 protein. Notably, this frameshift variant is recognized as one of the most common pathogenic variants in human osteochondromatosis. Our data suggest for the first time that genetic variants can have etiologic roles in osteochondromatosis in cats, as in humans and other animals.

Exostosis múltiple: variabilidad clínica y factores relacionados a la calidad de vida en niños y en adultos / Osteochondromatosis: clinical variability and factors related to quality of life in children and adults

Introducción. La exostosis múltiple hereditaria es una enfermedad poco frecuente autosómica dominante caracterizada por presencia de múltiples proyecciones óseas. Objetivo. Analizar factores asociados a la calidad de vida relacionada con la salud (CVRS) en niños >2 años y en adultos en seguimiento en un hospital de pediatría de alta complejidad de Argentina. Población y métodos. Estudio transversal de una cohorte en seguimiento. La CVRS se midió con Pediatric Quality of Life Inventory (PedsQL) y Short Form Health Survey (SF-36). Se registró sexo, edad, características sociodemográficas, estatura, radiología, alteración de eje y función de miembros, presencia de dolor y malignización. Se clasificó la gravedad según Pedrini y col. Se realizaron pruebas paramétricas, no paramétricas y análisis de regresión. Resultados. Se incluyeron 66 casos (47 niños y 19 adultos). Relación sexo masculino/femenino: 1,7/1. Mediana de edad: 13,4 años (r: 2,2155,3). Presentaron dolor 30 de 47 niños y 17 de 19 adultos. Si se considera la edad ósea adulta (o cierre epifisario) como punto de corte para definir el estado de adulto, 11 de 37 niños y 18 de 27 adultos presentaron forma grave de enfermedad, y se observó baja estatura en 2 de 38 niños y en 9 de 27 adultos. El valor promedio del componente físico de CVRS en niños fue 65,9 (DE: 22,5) y, en adultos, 27,2 (RIC: 18,5-34,7). La presencia de dolor y la gravedad clínica se asoció significativamente a menor CVRS tanto en niños como en adultos. Conclusiones. En este estudio se observó que el dolor y la gravedad de la enfermedad tuvieron un efecto negativo en la CVRS.

Introduction. Hereditary osteochondromatosis is an uncommon, autosomal, dominant condition characterized by the presence of multiple bone growths. Objective. To analyze factors associated with health-related quality of life (HRQoL) among children > 2 years and adults receiving follow-up at a tertiary care children's hospital in Argentina. Population and methods. Cross-sectional study of a follow-up cohort. HRQoL was measured using the Pediatric Quality of Life Inventory (PedsQL) and the Short Form Health Survey (SF36). Sex, age, sociodemographic characteristics, height, radiology, axis alteration and limb function, presence of pain, and malignant change were recorded. Severity was classified as per Pedrini et al. Parametric and non-parametric tests and regression analysis were done. Results. A total of 66 cases (47 children and 19 adults) were included. Male/female ratio: 1.7/1. Median age: 13.4 years (r: 2.21-55.3). Pain was observed in 30/47 children and in 17/19 adults. Considering the adult bone age (or epiphyseal closure) as the cutoff point to define adult status, 11/37 children and 18/27 adults had a severe disease and 2/38 children and 9/27 adults had short stature. The average value of the physical component of HRQoL in children was 65.9 (SD: 22.5) and, in adults, 27.2 (IQR: 18.534.7). The presence of pain and clinical severity were significantly associated with a lower HRQoL, both in children and adults. Conclusions. This study found that pain and disease severity had a negative effect on HRQoL.

Osteochondromatosis: clinical variability and factors related to quality of life in children and adults. / Exostosis múltiple: variabilidad clínica y factores relacionados a la calidad de vida en niños y en adultos.

INTRODUCTION: Hereditary osteochondromatosis is an uncommon, autosomal, dominant condition characterized by the presence of multiple bone growths. OBJECTIVE: To analyze factors associated with health-related quality of life (HRQoL) among children > 2 years and adults receiving follow-up at a tertiary care children's hospital in Argentina. POPULATION AND METHODS: Cross-sectional study of a follow-up cohort. HRQoL was measured using the Pediatric Quality of Life Inventory® (PedsQL) and the Short Form Health Survey (SF- 36). Sex, age, sociodemographic characteristics, height, radiology, axis alteration and limb function, presence of pain, and malignant change were recorded. Severity was classified as per Pedrini et al. Parametric and non-parametric tests and regression analysis were done. RESULTS: A total of 66 cases (47 children and 19 adults) were included. Male/female ratio: 1.7/1. Median age: 13.4 years (r: 2.21-55.3). Pain was observed in 30/47 children and in 17/19 adults. Considering the adult bone age (or epiphyseal closure) as the cutoff point to define adult status, 11/37 children and 18/27 adults had a severe disease and 2/38 children and 9/27 adults had short stature. The average value of the physical component of HRQoL in children was 65.9 (SD: 22.5) and, in adults, 27.2 (IQR: 18.5- 34.7). The presence of pain and clinical severity were significantly associated with a lower HRQoL, both in children and adults. CONCLUSIONS: This study found that pain and disease severity had a negative effect on HRQoL.

Introducción. La exostosis múltiple hereditaria es una enfermedad poco frecuente autosómica dominante caracterizada por presencia de múltiples proyecciones óseas. OBJETIVO: Analizar factores asociados a la calidad de vida relacionada con la salud (CVRS) en niños >2 años y en adultos en seguimiento en un hospital de pediatría de alta complejidad de Argentina. Población y métodos. Estudio transversal de una cohorte en seguimiento. La CVRS se midió con Pediatric Quality of Life Inventory® (PedsQL) y Short Form Health Survey (SF-36). Se registró sexo, edad, características sociodemográficas, estatura, radiología, alteración de eje y función de miembros, presencia de dolor y malignización. Se clasificó la gravedad según Pedrini y col. Se realizaron pruebas paramétricas, no paramétricas y análisis de regresión. RESULTADOS: Se incluyeron 66 casos (47 niños y 19 adultos). Relación sexo masculino/femenino: 1,7/1. Mediana de edad: 13,4 años (r: 2,21- 55,3). Presentaron dolor 30 de 47 niños y 17 de 19 adultos. Si se considera la edad ósea adulta (o cierre epifisario) como punto de corte para definir el estado de adulto, 11 de 37 niños y 18 de 27 adultos presentaron forma grave de enfermedad, y se observó baja estatura en 2 de 38 niños y en 9 de 27 adultos. El valor promedio del componente físico de CVRS en niños fue 65,9 (DE: 22,5) y, en adultos, 27,2 (RIC: 18,5-34,7). La presencia de dolor y la gravedad clínica se asoció significativamente a menor CVRS tanto en niños como en adultos. CONCLUSIONES: En este estudio se observó que el dolor y la gravedad de la enfermedad tuvieron un efecto negativo en la CVRS.

Osteocondromatosis sinovial de hombro. Una enfermedad poco frecuente / Shoulder synovial osteocondromatosis. A rare disease

RESUMEN La osteocondromatosis sinovial es una condición poco común que se caracteriza por la formación de nódulos cartilaginosos u óseos comúnmente visto en las articulaciones sobretodo en la rodilla, sin embargo en el hombro esta condición es rara. Presentamos un caso clínico de una mujer de 35 años de edad con dolor en hombro izquierdo de larga evolución, tratado de manera conservadora antes de ser referido a un ortopedista. Luego de un diagnostico clínico y radiológico se sometió a tratamiento quirúrgico en la que se realizó un desbridamiento y escisión de los cuerpos condrales con éxito. Palabras claves: Condromatosis sinovial, tratamiento, adulto joven, mujer

ABSTRACTSynovial osteochondromatosis is a rare condition characterized by the formation of cartilage or bone nodules commonly seen in the joints, especially in the knee, however, this condition is rare in the shoulder. We present a clinical case of a 35-year-old woman with a long history of left shoulder pain, treated conservatively before being referred to an orthopedist. After a clinical and radiological diagnosis, she underwent surgical treatment in which a successful debridement and excision of the chondral bodies was performed

Synovial sarcoma presenting as an intra-articular mass in a pediatric patient: a case report.

BACKGROUND: Synovial sarcoma (SS) is one of the reported sarcomas in the pediatric and adult populations. Delay in diagnosis and treatment is common in SS cases. SS may be excised before the correct diagnosis is made. CASE PRESENTATION: we present a case involving a 4-year-old boy who visited our service with complaints of left knee pain and limited knee flexion. Initially, the child was diagnosed with osteochondromatosis. Surgical excision was opted, and initial histopathological examination revealed a fibrous histiocytoma. The slide and blocks were then brought to the King Faisal Specialist Hospital Research Center (KFSH&RC) and histopathologic analysis has shown a well-circumscribed nodule in the synovium with a sub-synovial monomorphic spindle cell sarcoma, confirmed by fluorescence in situ hybridization (FISH). CONCLUSIONS: Therefore, we strongly recommend considering all differential diagnoses for soft-tissue masses when planning surgical management.

Diagnóstico de osteocondromatosis como hallazgo casual en cirugía de fallo de enclavado endomedular de cadera / Diagnosis of osteochondromatosis as an incidental finding in revision surgery after failed intramedullary nailing of the hip

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Clinical Results of Surgical Resection and Histopathological Evaluation of Synovial Chondromatosis in the Shoulder: A Retrospective Study and Literature Review

BACKGROUND: Synovial chondromatosis occurs rarely in the shoulder, and its details remain unclear. The purpose of this study was to clarify the clinical results of surgical resection and the histopathological findings of synovial chondromatosis in the shoulder.METHODS: Ten shoulders with synovial chondromatosis that had been operatively resected were reviewed retrospectively. Osteochondral lesions were present in the glenohumeral joint in six shoulders and in the subacromial space in four shoulders. Two patients had a history of trauma with glenohumeral dislocation without recurrent instability, and the other seven patients (eight shoulders) did not have any traumatic episodes or past illness involving the ipsilateral shoulder girdle. The occurrences of osteochondral lesions, inferior humeral osteophytes, and acromial spurs were assessed on radiographs before resection, just after resection, and at final follow-up. The Constant scores were compared before resection and at final follow-up with Wilcoxon signed-rank tests. Resected lesions were histopathologically differentiated between primary and secondary synovial chondromatosis.RESULTS: Inferior humeral osteophytes were found in five shoulders with synovial chondromatosis in the glenohumeral joint, and all four shoulders with synovial chondromatosis in the subacromial space had acromial spur formation. Osteochondral lesions appeared to have been successfully removed in all shoulders on postoperative radiographs. At the final follow-up, however, one shoulder with secondary synovial chondromatosis in the subacromial space showed recurrence of osteochondral lesions and acromial spur formation. The mean Constant score improved significantly from 53.0 points before resection to 76.0 points at a mean follow-up of 6.0 years (p = 0.002). On histopathological evaluation, one shoulder was diagnosed as having primary synovial chondromatosis, while nine shoulders had secondary synovial chondromatosis.CONCLUSIONS: The present study showed that resection of shoulder osteochondral lesions successfully relieved the clinical symptoms and that primary synovial chondromatosis is less common than secondary synovial chondromatosis in the shoulder. Although most of the present osteochondral lesions were clinically determined to be primary chondromatosis, only one case was histopathologically categorized as primary synovial chondromatosis. These results suggest that histopathological identification is needed to differentiate between primary and secondary synovial chondromatosis.

Surgical treatment of a rare bilateral synovial chondromatosis

Synovial chondromatosis (SC) in the temporomandibular joint (TMJ) is an uncommon entity, mostly when the involvement is bilateral. The authors report a rare case of bilateral SC, with a follow-up of 13 months, and a literature review. A 60-year-old Caucasian woman, with the chief complaint of pain for 6 years in the bilateral pre-auricular region, had a progressive clacking and discomfort on the left side during mouth opening. The panoramic image was suggestive of SC. The bilateral lesion was surgically removed by direct access. Histopathological examination confirmed the clinical diagnosis of bilateral SC. This article shows the importance of a multidisciplinary approach for the early diagnosis and appropriate treatment. Also, it encourages the referral of such cases to professionals with a greater familiarity with this entity.

Nora's Lesion: Bizarre Parosteal Osteochondromatous Proliferation Causing Splay Foot Deformity: A Case Report.

Nora's lesion, or bizarre parosteal osteochondromatous proliferation (BPOP), is a rare benign lesion that is made up of varying degrees of cartilage, bone, and spindle cells. Most notably, calcification of the cartilage or "blue bone," is a feature of the disorder. The condition principally affects long tubular bones of the hands and feet, and is generally seen in patients in their second and third decades of life. We present a case of BPOP occurring in the second interspace with symptoms that would be consistent with a more common diagnosis of predislocation syndrome, or a second interspace neuroma. This case study may help the clinician in considering a more subtle cause of a splay deformity in the second interspace, and walk through the diagnostic and treatment course for BPOP.

Osteochondromatosis (multiple cartilaginous exostoses) in an immature killer whale Orcinus orca.

An immature killer whale Orcinus orca found dead on the southeastern Brazilian coast had multiple bone proliferations: on the skull, vertebrae, hemal arches, and ribs. The bony formations were characterized as multiple osteochondromas, as defined by osteochondromatosis. The diagnosis was based on macroscopic and radiographic observations. These benign osseocartilaginous tumors affect young individuals and grow until skeletal maturity is achieved. Case reports of this condition, besides humans, include other mammals, with most reports for pets and domestic mammals such as cattle, and a report in a fossil canid (Hesperocyon) from the Oligocene. The etiology, diagnosis, developmental characteristics, and occurrence of osteochondromas are distinct among different species. This report describes the first case of multiple osteochondromas in a wild cetacean.

Analysis of mutations in EXT1 and EXT2 in Brazilian patients with multiple osteochondromas.

BACKGROUND: Multiple osteochondromas is a dysplasia characterized by growth of two or more osteochondromas. It is genetically heterogeneous, caused by pathogenic variants in EXT1 or EXT2 genes in 70%-90% of patients. The EXT1 is more often mutated than EXT2 gene, with a variable prevalence between populations. There are no data about EXT1 and EXT2 pathogenic variants in patients with multiple osteochondromas in Brazilian population. The aim of this survey is to characterize these to determine the genotype profile of this population. METHODS: DNA sequencing (Sanger Method) and MLPA analysis were performed to identify point mutations and deletions/duplications in the sample of 153 patients in 114 families. RESULTS: Germline variants were identified in 83% of families in which EXT2 variants were detected in 46% and EXT1 in 37% of cases. No variants were detected in 17% of them. We identified 50 different variants, 33 (13 frameshift, 11 nonsense, 5 missense, 2 splice site mutation, and 2 large deletions) in EXT1 and 17 (6 frameshift, 6 splice site mutation, 3 nonsense, 1 missense, and 1 large deletion) in EXT2. Of all 50 variants, 31 (62%) were novel, including 20 out of 33 (60,6%) EXT1 and 11 out of 17 (64.7%) EXT2 alleles. The vast majority of variants (88%) were "loss-of-function" and two novel hotspots in EXT2 gene were observed in our study. CONCLUSION: The prevalence of variants detected in the EXT2 gene differs from other researches from Latin America, European, and Asian population. This uncommon prevalence could be related with the newly characterized variant hotspot sites detected in EXT2 gene (p.Ala409Profs*26 and p.Ser290*). A high number of novel variants were also identified indicating that Brazilian population has a unique genetic profile. Characterizing this population and establishing its genotype is essential to understand the molecular pathogenesis of this disease in Brazil.

A de novo mutation in the EXT2 gene associated with osteochondromatosis in a litter of American Staffordshire Terriers.

BACKGROUND: We aimed to identify mutations associated with osteochondromatosis in a litter of American Staffordshire Terrier puppies. HYPOTHESIS: We hypothesized that the associated mutation would be located in a gene that causes osteochondromatosis in humans. ANIMALS: A litter of 9 American Staffordshire puppies, their sire and dam, 3 of 4 grandparents, 26 healthy unrelated American Staffordshire Terriers, and 154 dogs of 27 different breeds. METHODS: Whole genome sequencing was performed on the proband, and variants were compared against polymorphisms derived from 154 additional dogs across 27 breeds, as well as single nucleotide polymorphism database 146. One variant was selected for follow-up sequencing. Parentage and genetic mosaicism were evaluated across the litter. RESULTS: We found 56,301 genetic variants unique to the proband. Eleven variants were located in or near the gene exostosin 2 (EXT2), which is strongly associated with osteochondromatosis in humans. One heterozygous variant (c.969C > A) is predicted to result in a stop codon in exon 5 of the gene. Sanger sequencing identified the identical mutation in all affected offspring. The mutation was absent in the unaffected offspring, both parents, all available grandparents, and 26 healthy unrelated American Staffordshire Terriers. CONCLUSIONS AND CLINICAL IMPORTANCE: These findings represent the first reported mutation associated with osteochondromatosis in dogs. Because this mutation arose de novo, the identical mutation is unlikely to be the cause of osteochondromatosis in other dogs. However, de novo mutations in EXT2 are common in humans with osteochondromatosis, and by extension, it is possible that dogs with osteochondromatosis could be identified by sequencing the entire EXT2 gene.

Synovial Osteochondromatosis of the Subtalar Joint in an Adolescent Baseball Player / 대한스포츠의학회지

Synovial chondromatosis is an uncommon disorder characterized by cartilaginous proliferation within the synovial membrane of the articular joint. Smaller joints are rarely affected and it may be progressed to osteochondromatosis after ossification or calcification of metaplastic cartilage. It is commonly presented in the third to fourth decade of life, but rarely presented in adolescence. We report a unique case of synovial osteochondromatosis of the subtalar joint in 14-year-old baseball player. Arthroscopic removal of loose body and complete excision of the osteochondral mass with concomitant synovectomy resulted in satisfactory outcome without recurrence at final follow-up.

Osteocondromatose em gato: relato de caso / Osteochondromatosis in a cat: case report

A osteocondromatose é caracterizada por nódulos únicos ou múltiplos decorrentes de um crescimento ósseo excessivo benigno. É encontrada em cães, gatos, equinos e humanos. Em felinos, tem maior incidência dos dois aos quatro anos de idade. A etiologia em gatos está relacionada ao vírus da leucemia felina, e também já foi encontrada relação com o fibrossarcoma. A manifestação clínica depende do local acometido e do tamanho da lesão. O diagnóstico definitivo é por meio de histopatologia e o prognóstico é desfavorável, pois ocorrem muitas recidivas. Este relato de caso objetiva descrever a apresentação dessa enfermidade em um felino jovem.(AU)

Osteochondromatosis is characterized by single or multiple nodules resulting from benign excessive bone growth. It is found in cats and dogs, horses and humans. In cats, a higher incidence is found in individuals from 2 to 4 years of age. The etiology in cats is related to the virus of feline leukemia, and is also related to fibrosarcoma. The clinical presentation depends on the area affected and the size of the lesion. The definitive diagnosis is by histopathology and the prognosis is poor because many relapses occur. This case report aims to describe the presentation of the disease in a young cat.(AU)