A somatic activating KRAS variant identified in an affected lesion of a patient with Gorham-Stout disease.

Gorham-Stout disease (GSD), a rare disorder of unknown etiology, is characterized by massive osteolysis that is associated with proliferation and dilation of lymphatic vessels. Variants in cancer-associated genes have been described in complex lymphatic anomalies. To explore the pathogenesis of GSD, we performed the amplicon-based deep sequencing on 50 cancer-related genes to assay affected tissues from the six patients with GSD. In one patient, a somatic activating KRAS c.182A > G variant (p.Q61R) was detected in 1% of the tissue sample. Conversely, the mutant allele was not detected in uninvolved normal skin and blood samples. Histopathology of the patient's tissue sample showed proliferation of abnormal lymphatic and blood vascular endothelial cells, osteoclasts, and activated macrophages. The activating KRAS variant is a known 'hotspot' variant, frequently identified in several types of human cancer. This is the first report of identifying a pathogenic variant in a patient with GSD. This finding may set the stage for elucidation of pathophysiology and the development of novel therapies for GSD.

The Impact of Mast Cell Density on the Progression of Bone Disease in Multiple Myeloma Patients.

BACKGROUND: Osteolytic bone disease is a major hallmark in multiple myeloma (MM) progression and affects many patients. Several inflammatory cells are involved in MM progression. Among them, mast cells (MCs) accumulated in the bone marrow (BM) microenvironment are known to play an important role in the mechanism of neovascularization. METHODS: In 52 newly diagnosed active MM patients, we measured BM MC density (MCD) using an immunohistochemical stain for tryptase, serum levels of matrix metalloproteinase-9 (MMP-9) and receptor activator of nuclear factor x03BA;B ligand (RANKL) by a solid-phase sandwich enzyme-linked immunosorbent assay, along with urine levels of N-terminal propeptide of procollagen type I (Ntx) by a competitive inhibition enzyme-linked immunosorbent assay, in various clinical stages and skeletal grades. RESULTS: MCD, RANKL and Ntx were higher in MM patients. All values increased in association with both the clinical stage and skeletal grade. Furthermore, MCD correlated positively with MMP-9, RANKL and Ntx. CONCLUSIONS: Our data suggest that MCs may contribute to osteolytic processes during MM progression. Although the major role of MCs in tumor progression is to enhance angiogenesis, it seems that they may affect MM bone disease and may secrete a plethora of mediators that may directly and indirectly have an impact on osteolysis.

PTEN hamartoma tumor syndrome and Gorham-Stout phenomenon.

PTEN: hamartoma tumor syndrome (PHTS) is a group of syndromes caused by mutations in PTEN. Gorham-Stout phenomenon (GSP) is a rare condition characterized by proliferation of vascular structures in bones, resulting in progressive osteolysis. Here we present a 1-year-old boy with PHTS and GSP. The lesion that later proved to be GSP was evident from the age of 4 months, and became symptomatic at the age of 1 year. Eventually, he developed a fatal chylothorax. Mutation analysis revealed a germline heterozygous mutation c.517 C>T (p.Arg173Cys) in exon 6 of PTEN. Analysis of the lymphatic malformation (LM) tissue revealed no loss of heterozygosity (LOH) nor a second, somatic PTEN mutation of the remaining wild type allele. The germline p.Arg173Cys mutation was also present in the mother and the propositus' younger sister and brother. Further molecular work-up showed a heterozygous variant c.2180C>T (p.Ala727Val) FLT4 in the LM tissue, which was also present in the germline of mother and two siblings. GSP has not been reported before in a patient with a PTEN mutation. Up to this date, this mutation is the only genetic defect possibly involved in the etiology of GSP which is plausible given the known function of PTEN in angiogenic signaling.

Gorham-Stout case report: a multi-omic analysis reveals recurrent fusions as new potential drivers of the disease.

BACKGROUND: Gorham-Stout disease is a rare condition characterized by vascular proliferation and the massive destruction of bone tissue. With less than 400 cases in the literature of Gorham-Stout syndrome, we performed a unique study combining whole-genome sequencing and RNA-Seq to probe the genomic features and differentially expressed pathways of a presented case, revealing new possible drivers and biomarkers of the disease. CASE PRESENTATION: We present a case report of a white 45-year-old female patient with marked bone loss of the left humerus associated with vascular proliferation, diagnosed with Gorham-Stout disease. The analysis of whole-genome sequencing showed a dominance of large structural DNA rearrangements. Particularly, rearrangements in chromosomes seven, twelve, and twenty could contribute to the development of the disease, especially a gene fusion involving ATG101 that could affect macroautophagy. The study of RNA-sequencing data from the patient uncovered the PI3K/AKT/mTOR pathway as the most affected signaling cascade in the Gorham-Stout lesional tissue. Furthermore, M2 macrophage infiltration was detected using immunohistochemical staining and confirmed by deconvolution of the RNA-seq expression data. CONCLUSIONS: The way that DNA and RNA aberrations lead to Gorham-Stout disease is poorly understood due to the limited number of studies focusing on this rare disease. Our study provides the first glimpse into this facet of the disease, exposing new possible therapeutic targets and facilitating the clinicopathological diagnosis of Gorham-Stout disease.

KRAS-driven model of Gorham-Stout disease effectively treated with trametinib.

Gorham-Stout disease (GSD) is a sporadically occurring lymphatic disorder. Patients with GSD develop ectopic lymphatics in bone, gradually lose bone, and can have life-threatening complications, such as chylothorax. The etiology of GSD is poorly understood, and current treatments for this disease are inadequate for most patients. To explore the pathogenesis of GSD, we performed targeted high-throughput sequencing with samples from a patient with GSD and identified an activating somatic mutation in KRAS (p.G12V). To characterize the effect of hyperactive KRAS signaling on lymphatic development, we expressed an active form of KRAS (p.G12D) in murine lymphatics (iLECKras mice). We found that iLECKras mice developed lymphatics in bone, which is a hallmark of GSD. We also found that lymphatic valve development and maintenance was altered in iLECKras mice. Because most iLECKras mice developed chylothorax and died before they had significant bone disease, we analyzed the effect of trametinib (an FDA-approved MEK1/2 inhibitor) on lymphatic valve regression in iLECKras mice. Notably, we found that trametinib suppressed this phenotype in iLECKras mice. Together, our results demonstrate that somatic activating mutations in KRAS can be associated with GSD and reveal that hyperactive KRAS signaling stimulates the formation of lymphatics in bone and impairs the development of lymphatic valves. These findings provide insight into the pathogenesis of GSD and suggest that trametinib could be an effective treatment for GSD.

Massive cranial osteolysis, skin changes, growth retardation and developmental delay: Gorham syndrome with systemic manifestations?

We report on a 16-month-old girl with multiple swellings on her skull due to massive osteolysis, growth retardation, facial anomalies, and wrinkly skin with mosaic hypopigmentation. She also had severe hypercalcemia, which gradually returned to normal levels. The condition likely represents Gorham syndrome with systemic manifestations.

Successful Management of Gorham-Stout Disease in Scapula and Ribs: A Case Report and Literature Review.

Gorham-Stout disease (GSD) is an extremely rare bone condition of unknown etiology characterized by spontaneous and progressive resorption of bones. GSD can occur at any age and is not related to gender, genetic inheritance, or race. Any part of the skeleton can be affected and the symptoms correlate with the sites involved. The diagnosis of GSD is established based on the combination of clinical, radiologic, and histologic features after excluding other diseases. Because of its rarity, current knowledge is limited to case reports and there is no agreement on the best strategy for treatment. The following case report describes a successfully treated case of GSD in a 26-year-old male patient with the left scapula and the 7th-9th left ribs involved. The patient was diagnosed with osteoporosis-related pleural effusion at a local hospital. In our institution, the patient was diagnosed with GSD and treated with radiotherapy and bisphosphonate. The disease was controlled and there was no evidence of disease progression during follow-up. Genetic sequencing was performed to investigate the etiology of GSD. In addition, the present study reviews the theories regarding the etiology, the clinical manifestations, the diagnostic approaches, and treatment options for this rare disease.

Hereditary bilateral conductive hearing loss caused by total loss of ossicles: a report of familial expansile osteolysis.

OBJECTIVE: The objective of this study was to report on three members of a family with familial expansile osteolysis; the important point about these patients was that none of them had middle-ear ossicles. STUDY DESIGN AND SUBJECTS: A retrospective case review including three cases with familial expansile osteolysis. SETTING: Department of Otolaryngology in a tertiary referral center. INTERVENTIONS: Each patient underwent computerized tomography of the temporal bone in the coronal view, audiometric and tympanometric evaluations, biochemical investigation, whole body isotope scans by Tc-99 mMDP and X-ray. Also the patients' pedigree was studied. Two of the patients had exploratory middle-ear surgery as well. RESULTS: The temporal-bone computed-tomography scan in the coronal view of all three patients and also exploratory middle-ear surgery, which was done on two of the patients, showed no ossicles in the middle ear of either ear in all three cases. This feature hadn't been reported in previous studies. Hearing loss was revealed in the medical histories since childhood. Audiometry indicated mild to moderate conductive and mixed hearing loss and also an AD-type tympanogram pattern along with an absence of acoustic reflexes in both ears of the cases. Both serum alkaline phosphatase and hydroxyproline levels were elevated. There was an increase in uptake and activity at multiple foci of the whole skeleton. No improvement in hearing thresholds was obtained after reconstruction of the middle ear. CONCLUSION: The total absence of middle-ear ossicles can probably be regarded as a new symptom in some patients with familial expansile osteolysis. Common ossiculoplasty for improving the hearing thresholds in this condition may be unsuccessful; therefore, both surgeons and patients must be completely aware of the contingent undesirable results.

Severe osteoporosis in familial Hajdu-Cheney syndrome: progression of acro-osteolysis and osteoporosis during long-term follow-up.

Hajdu-Cheney syndrome is an autosomal dominant inherited osteodysplastic bone disease with the hallmarks of acro-osteolysis, skull deformations, and generalized osteoporosis. Very few patients have been followed long-term with respect to the prognosis of acro-osteolysis and osteoporosis. Here we describe a 39-year-old woman and her 19-year-old daughter who are both affected with the Hajdu-Cheney syndrome. Skeletal lesions were followed in the mother between the ages of 22 and 39 years. The acro-osteolytic lesions progressed markedly and caused shortening of several fingers; some end phalanges had completely disappeared. Severe spinal osteoporosis with serial vertebral fractures was found at the age of 22 years. New vertebral fractures developed until the age of 33 years, but did not progress afterward. High turnover osteoporosis was found in the bone histology of iliac crest biopsies performed at the ages of 22 and 34 years. Bone mineral content (BMC) was strikingly decreased at the age of 34 years (T score -5.1 SD) and did not significantly change during further follow-up. In the daughter, BMC failed to increase between the ages of 12 and 19 years and was also markedly decreased (T score -4.4 SD). This suggests that osteoporosis in Hajdu-Cheney syndrome is related to a low peak bone mass and a high bone turnover, leading to insufficient bone formation compared with the increased bone resorption.

Idiopathic multicentric osteolysis: report of two new cases and a review of the literature.

Idiopathic multicentric osteolysis is a rare skeletal disorder, usually presenting in early childhood with a clinical picture mimicking juvenile rheumatoid arthritis. Progressive destruction of the carpal and tarsal bones usually occurs and other bones may also be involved. Chronic renal failure is a frequent component of this syndrome. Mental retardation and minor facial abnormalities have been noted in some patients. We report on 2 unrelated, sporadic cases, one with facial anomalies and the other with nephropathy. Our second patient is the first black child to be diagnosed with this disease. The mode of presentation, differential diagnosis, and natural history of this disorder are briefly reviewed.

Cystic kidney disease in Hajdu-Cheney syndrome.

We report on 2 unrelated patients with Hajdu-Cheney acroosteolysis syndrome, who had cystic kidneys with ultrasonographic changes similar to those of autosomal dominant polycystic kidney disease. Neither had a family history of Hajdu-Cheney syndrome or polycystic kidneys, nor manifestations of any other syndrome. On the basis of the findings in these 2 patients and a review of published cases, we suggest that cystic kidneys are an important component of Hajdu-Cheney syndrome.

Distal osteolysis, short stature, mental retardation, and characteristic facial appearance: delineation of an autosomal recessive subtype of essential osteolysis.

We describe the concurrence of severe distal osteolysis, mental retardation, short stature, and characteristic facial appearance with maxillary hypoplasia and relative exophthalmos in two adult sibs, a 57-year-old woman and her deceased brother. Apparently they represent a distinct, autosomal recessive entity in the group of the so-called essential osteolysis. Furthermore, this observation confirms that the facial changes that may occur in patients with essential osteolysis, ie, maxillary hypoplasia and relative exophthalmos, may be present in all types of osteolysis, independent of their localisation or inheritance.

Expansile bone lesions in a three-generation family.

We report on a three-generation family with "expansile" bone lesions of the distal radius and ulna, cortical thickening of the proximal long bones, and pathologic fractures. The differential diagnosis of expansile bone lesions includes isolated bone cysts and tumors, such as enchondromas and fibrous dysplasia; familial expansile osteolysis; and the genochondromatoses. Our patients have findings most similar to the genochondromatoses; however, the distribution of the lesions and the accompanying manifestations may be evidence for a unique genetic condition in this family.

Inherited multicentric osteolysis with arthritis: a variant resembling Torg syndrome in a Saudi family.

The autosomal recessive multicentric osteolytic disorders of childhood-Torg, Winchester, and François syndromes-predominantly affect the carpal, tarsal, and interphalangeal joints, and their progressive bone loss and crippling arthritic deformities mimic severe juvenile rheumatoid arthritis. In a consanguineous Saudi Arabian family two affected sibs with facial anomalies and short stature displayed a distal arthropathy of the metacarpal, metatarsal, and interphalangeal joints starting in the first few months of life that eventually progressed to the proximal joints and resulted in crippling ankylosis and severe generalized osteopenia. Facial changes included proptosis, a narrow nasal bridge, bulbous nose, and micrognathia. In addition, they had large, painful fibrocollagenous palmar and plantar pads and mild body hirsutism. Affected individuals were of normal intelligence and had normal renal function. Routine hematologic, chemistry, and rheumatoid studies were within normal limits. Histologic examination of bone marrow and an interphalangeal joint biopsy were not informative. The autosomal recessive inheritance, clinical, and radiologic characteristics of the affected sibs suggested that they had a form of multicentric osteolysis most closely resembling the Torg syndrome, but with a unique facial appearance, fibrocollagenous pads, and body hirsutism not noted in the original description of the syndrome.

Hajdu--Cheney syndrome: evolution of phenotype and clinical problems.

Hajdu-Cheney syndrome is a rare, autosomal dominant disorder comprising acroosteolysis of the distal phalanges with associated digital abnormalities, distinctive craniofacial and skull changes, dental anomalies, and proportionate short stature. The clinical and radiologic characteristics of Hajdu-Cheney syndrome develop and progress with age. Many of the medical problems that arise in this syndrome cluster in specific age ranges. Case reports of six affected individuals in two additional families and a summary of the English literature is presented with emphasis on the changing physical findings and medical sequelae over time.

Pregnancy complicated by Gorham disease.

BACKGROUND: A pregnancy with Gorham disease (massive osteolysis syndrome) is described. To our knowledge, this is the first reported case of a pregnancy associated with this disease. CASE: A 25-year-old woman was seen for pre-conception counseling with the diagnosis of Gorham disease. Before pregnancy, magnetic resonance imaging confirmed a stable disease process. The woman and fetus were followed during pregnancy with ultrasound and consultations. Severe preeclampsia developed at delivery, with a significant thrombocytopenia. We delivered the infant by low forceps, with a good outcome. Subsequently, the mother and child were doing well at 18 months postpartum. CONCLUSION: We briefly review this rare bone disease as it relates to pregnancy and provide information for preconception counseling.

Carpo-tarsal osteolysis. Case report and review of the literature.

A hereditary form of multicentric osteolysis is described in an 11-year-old girl whose father is also affected. The results after corrective surgery on the foot with the Ilizarov fixator and the findings during arthroscopy of the knee are discussed. The literature is reviewed.

Idiopathic multicentric osteolysis: family report and review of the literature.

A mother and son affected by idiopathic multicentric osteolysis are reported. This condition usually manifests in early childhood and is characterized by progressive destruction of the carpal and tarsal bones, with or without renal anomalies. Unusual facies might be the clinical features of the syndrome. Review of the literature shows that osteolysis can occur in isolation or may be associated with renal and/or facial anomalies.

[Acro-osteolysis]. / Die Akroosteolyse.

A case of essential carpal osteolysis is reported. The morphological appearance of the hands is described. They showed ulnar deviation; they were short and pudgy, the carpus and metacarpus being almost absent. The fingers were normal, but the left thumb was atrophic. Radiographies of the left hand showed an almost complete disappearance of the carpus and severe irregularities of the ulna and radius. Aetiology, treatment and prognosis are briefly discussed.

[Heterogenicity of Gorham-Stout syndrome: association with lymphatic and venous malformations]. / Heterogenicidad del síndrome de Gorham-Stout: asociación a malformaciones linfáticas y venosas.

INTRODUCTION: Gorham-Stout syndrome is a rare disorder of unknown etiology characterized by osteolysis and microscopic proliferation of abnormal vessels. We report two cases of this syndrome associated with lymphatic and venous malformations. CASE REPORTS: The first case is a 5-year-old boy with disseminated lymphangiomatosis of poor prognosis, with significant pleural involvement and osteolytic lesions. The second case is a 5-year-old girl with a diagnosis of Klippel-Trenaunay syndrome with significant skeletal involvement of the lower extremities and secondary pathological fracture. CONCLUSIONS: Gorham-Stout syndrome may occasionally be associated with various lymphatic and venous malformations. Osteolysis and bone resorption may be induced by lymphatic bone involvement.