Calculating minimum safety distance against wildfires at the wildland-urban interface in Chile and Spain.

Wildfires in the urban-forest interface constitute a civil protection emergency, causing considerable personal injury and damage to properties. The potential impacts of wildfires on buildings can be minimized by reducing the surrounding fuel and the use of structural materials with low flammability. However, the costs associated with implementing these actions and the responsibility for maintenance usually present conflicts with the property owners. This study aimed to identify minimum safety distances in wildland-urban interfaces within priority areas. The priority areas were identified based on the integration of fire risk and fuel hazard. Radiant heat is a variable in the behavior of fire that directly influences the definition of safety distances. In this research the radiant heat transfer was calculated based on the potential fire behavior for each study area. A comparative study of the horizontal heat transfer method and the radiant heat flux model was carried out. The horizontal heat transfer method indicated the highest vegetation-free distances, ranging from 23 m to 32 m. Some safety distances were validated using experimental fires and wildfires. The findings from the experimental fires and wildfires emphasize the need for a progressive fuel load reduction to mitigate radiant heat transfer. This may include both the removal of surface fuel and removal of trees to mitigate against crown fires. Our findings provide relevant information for decision-making on the effectiveness and efficiency of safety distances at the wildland-urban interface.

Rosai-Dorfman Disease of Bone and Soft Tissue.

CONTEXT.­: Rosai-Dorfman disease is a rare histiocytic proliferative disorder of unknown pathogenesis that may be diagnostically difficult in extranodal sites. It is commonly an unsuspected diagnosis when arising in bone and soft tissue, especially when it presents without associated lymphadenopathy. Its variable clinical presentation and nonspecific imaging findings make the diagnosis quite challenging, particularly in small biopsies. The problem is compounded by its less-characteristic histomorphologic features in comparison with nodal disease. Awareness of the potential diagnostic pitfalls in Rosai-Dorfman disease of bone and soft tissue should raise the degree of diagnostic accuracy. OBJECTIVE.­: To review the clinical manifestations, imaging characteristics, and histomorphologic features of Rosai-Dorfman disease of bone and soft tissue along with a brief discussion of its differential diagnosis, pathogenesis, and current management. DATA SOURCES.­: Thorough review of the literature with focus on clinical manifestations, imaging findings, key histomorphologic features, pathogenesis, and treatment. CONCLUSIONS.­: The diagnosis of Rosai-Dorfman disease of bone and soft tissue may be quite challenging because of its variable clinical presentation and nonspecific imaging findings. It may be asymptomatic without systemic manifestations or associated lymphadenopathy. The definitive diagnosis relies on histopathologic identification of the characteristic S-100-positive histiocytes demonstrating emperipolesis. Bone and soft tissue lesions tend to have lower numbers of characteristic histiocytes and less conspicuous emperipolesis and often demonstrate areas of fibrosis or storiform spindle cell areas resembling fibrohistiocytic lesions. Awareness of these unusual features is necessary in order to consider Rosai-Dorfman disease in the differential diagnosis when confronting these rare and often misleading lesions.

Differentiation of Saccadic Eye Movement Signals.

Saccadic electrooculograms are discrete biosignals that contain the instantaneous angular position of the human eyes as a response to saccadic visual stimuli. These signals are essential to monitor and evaluate several neurological diseases, such as Spinocerebellar Ataxia type 2 (SCA2). For this, biomarkers such as peak velocity, latency and duration are computed. To compute these biomarkers, we need to obtain the velocity profile of the signals using numerical differentiation methods. These methods are affected by the noise present in the electrooculograms, specially in subjects that suffer neurological diseases. This noise complicates the comparison of the differentiation methods using real saccadic signals because of the impossibility of establishing exact saccadic onset and offset points. In this work, we evaluate 16 differentiation methods by the design of an experiment that uses synthetic saccadic electrooculograms generated from parametric models of both healthy subjects and subjects suffering from Spinocerebellar Ataxia type 2 (SCA2). For these synthetic electrooculograms the exact velocity profile is known, hence we can use them as a reference for comparison and error computing for the tasks of saccade identification and saccade biomarker computing. Finally, we identify the best fitting method or methods for each evaluated task.

Epiphyseal Ewing Sarcoma in a skeletally mature patient: A case report and review of the literature.

While Ewing sarcoma of bone is the second most common primary osseous malignancy in childhood where it typically involves the diaphysis or metadiaphyses of long bones of skeletally immature patients, primary epiphyseal involvement of the long bone in skeletally mature patients is rare with no cases reported in the literature to our knowledge, rendering this case the first of its kind. We present the first case of primary Ewing Sarcoma of the epiphyses of the long bones in a skeletally mature 20-year-old male patient. The patient initially presented with left knee stiffness and pain that was empirically treated with non-steroidal anti-inflammatory medications. His pain progressed despite treatment. An x-ray of the left knee was obtained 5 months later demonstrating an irregular lucent lesion in the medial femoral condyle. A subsequent MRI revealed an enhancing lesion in the medial femoral condyle, and when biopsied it was consistent with Ewing sarcoma (positive for EWSR1gene rearrangement by fluorescence in situ hybridization). The lesion was resected surgically, and the patient underwent neoadjuvant chemotherapy with a good clinical outcome.

Giant Cell Tumor of Distal Radius After Open Reduction Internal Fixation for Distal Radius Fracture.

CASE: A 77-year-old woman presented with volar wrist pain 1.5 years after undergoing distal radius volar locked plating for fracture. Radiographs and CT were notable only for plate prominence, and she was admitted for removal of hardware. Intraoperatively, a large cavitary bone lesion was found. Histopathology demonstrated a giant cell tumor of the bone. Definitive management consisted of wide en bloc resection and osteoarticular allograft reconstruction, which achieved local control and an acceptable clinical result. CONCLUSION: Although not previously described, a giant cell tumor of the bone may develop after fracture. Metal artifact in an area of previous internal fixation can make recognition challenging, but dual-energy CT can be used to decrease this artifact. Local control can be achieved with wide excision and reconstruction.

NFAT restricts osteochondroma formation from entheseal progenitors.

Osteochondromas are common benign osteocartilaginous tumors in children and adolescents characterized by cartilage-capped bony projections on the surface of bones. These tumors often cause pain, deformity, fracture, and musculoskeletal dysfunction, and they occasionally undergo malignant transformation. The pathogenesis of osteochondromas remains poorly understood. Here, we demonstrate that nuclear factor of activated T cells c1 and c2 (NFATc1 and NFATc2) suppress osteochondromagenesis through individual and combinatorial mechanisms. In mice, conditional deletion of NFATc1 in mesenchymal limb progenitors, Scleraxis-expressing (Scx-expressing) tendoligamentous cells, or postnatally in Aggrecan-expressing cells resulted in osteochondroma formation at entheses, the insertion sites of ligaments and tendons onto bone. Combinatorial deletion of NFATc1 and NFATc2 gave rise to larger and more numerous osteochondromas in inverse proportion to gene dosage. A population of entheseal NFATc1- and Aggrecan-expressing cells was identified as the osteochondroma precursor, previously believed to be growth plate derived or perichondrium derived. Mechanistically, we show that NFATc1 restricts the proliferation and chondrogenesis of osteochondroma precursors. In contrast, NFATc2 preferentially inhibits chondrocyte hypertrophy and osteogenesis. Together, our findings identify and characterize a mechanism of osteochondroma formation and suggest that regulating NFAT activity is a new therapeutic approach for skeletal diseases characterized by defective or exaggerated osteochondral growth.

A 15-Year-Old Male Baseball Player With a Mass in the Brachialis Muscle.

A 15-year-old boy presented with a mass in his right arm after suffering a minor injury playing baseball. He had been diagnosed with a hematoma. There was no other outstanding medical/surgical history. Magnetic resonance images showed a heterogeneous mass arising from the brachialis muscle that mainly enhanced peripherally with extremely scant internal nodular enhancement. Core needle biopsy cells were positive for CD31 and CD34, markers for atypical endothelial cells, as well as MIB-1 and p53. The final diagnosis was an angiosarcoma of the brachialis muscle. Pediatric angiosarcoma, particularly within deep tissue, is exceedingly rare. Histological and immunohistochemical modalities led to the diagnosis. Magnetic resonance images suggested a mass with a large cystic/hemorrhagic space that could have been misconstrued as a hematoma had there been absolutely no nodular or septal enhancement. The patient underwent neoadjuvant chemotherapy and radiation before undergoing limb-sparing surgery that included resection of the mass with the brachialis muscle and short head of the biceps muscle. Neoadjuvant treatment was deemed successful due to a drastic reduction in the size of the tumor and 95% tumor necrosis. The patient was disease free 2 years postoperatively. There had been no local/systemic recurrences. He was pain free, had normal elbow function, and had returned to playing baseball. It is important to be extremely suspicious when a patient presents with a hemorrhagic, painless, enlarging mass after sustaining minor trauma. A careful and meticulous biopsy must be completed to achieve the correct diagnosis. Magnetic resonance imaging with gadolinium is recommended for evaluation because these masses can be often misinterpreted as hematomas. [Orthopedics. 2016; 39(3):e545-e548.].

Chondroid Syringoma of the Foot: A Rare Diagnosis.

Chondroid syringoma is a rare tumor with the potential for malignant transformation and distant metastasis. The site of predilection for benign chondroid syringoma is the head and neck region, and it is less likely to involve the foot. In contrast, malignant chondroid syringoma is more commonly encountered in the extremities and is characterized by rapid growth, local invasion, and distant metastasis. We report an unusual case of benign chondroid syringoma in a 47-year-old female who presented with a 20-year history of a mass in her left foot to bring such cases to the attention of foot and ankle specialists. We highlight the histologic diagnosis and surgical procedures with a 6-month postoperative follow-up period. It is unlikely that a treating physician would anticipate this histologic tumor type, considering the rarity of the condition, the long history of this patient's lesion, and the benign presentation in the extremities.

Recurrent temporal bone tenosynovial giant cell tumor with chondroid metaplasia: the use of imaging to assess recurrence.

Tenosynovial giant cell tumor (TGCT) is a benign proliferative lesion of unclear etiology. It is predominantly monoarticular and involves the synovium of the joint, tendon sheath, and bursa. TGCT of the temporomandibular joint (TMJ) is rare and aggressive resulting in destruction of surrounding structures. The diagnosis may be suggested by imaging, mainly by the MR features and PET/CT, and confirmed by histopathology. We describe the case of a 50-year-old man who presented with right-sided hearing loss, tinnitus and TMJ pain. Pathology revealed tenosynovial giant cell tumor with chondroid metaplasia. Six years later he developed a recurrence, which was documented to our knowledge for the first time with CT, MR and FDG PET/CT imaging.

Myofibroblastic differentiation of stromal cells in giant cell tumor of bone: an immunohistochemical and ultrastructural study.

The nature of the mononuclear stromal cells (MSCs) in giant cell tumor of bone (GCTB) has not been thoroughly investigated. The purpose of this study was to evaluate the degree and significance of myofibroblastic differentiation in 18 cases of GCTB by immunohistochemistry (IH) and/or electron microscopy (EM). All immunostained cases were found positive for smooth muscle actin (SMA) and/or muscle specific actin (MSA), most in 1-33% of the MSCs. Ultrastructurally, most MSCs were fibroblasts, and a significant number of cells displayed myofibroblastic differentiation. Myofibroblasts are an important component of MSCs in GCTB. The myofibroblastic population may be responsible in part for the production of matrix metalloproteinases (MMPs), which probably play a role in bone destruction, tumor aggression, and recurrence.

Intraosseous ganglion cyst within the L4 lamina causing spinal stenosis.

BACKGROUND CONTEXT: There are rare reports of intraosseous ganglion cysts in the cervical spine. However, to our knowledge, there are no previous reports of these cysts occurring in the lumbar spine. PURPOSE: To report a case of symptomatic lumbar spinal stenosis caused by an intraosseous ganglion cyst of the L4 lamina that communicated with the spinal canal. STUDY DESIGN: Case report. METHODS: An 86-year-old woman was referred to our spine service for a 2-year history of anterior thigh and leg pain. Magnetic resonance imaging revealed a benign-appearing intraosseous cyst in the left L4 lamina communicating with a posterior epidural cyst at L4-L5 causing marked spinal stenosis. The patient was treated successfully with a laminectomy and resection. RESULTS: The patient underwent partial laminectomies of L4 and L5 preserving the interspinous ligaments between L5-S1 and L3-L4. The cyst was removed en bloc without violation of the cyst wall. Histopathologic examination revealed focal myxoid changes without a cellular lining of the cyst wall, confirming the diagnosis of intraosseous ganglion cyst. CONCLUSIONS: This is the first report to describe an intraosseous ganglion cyst occurring in the lumbar spine. Although spinal stenosis is commonly a result of degenerative joint or disc disease, it occasionally may result from more obscure causes. This case illustrates a patient with an intraosseous ganglion cyst within the spinal lamina resulting in spinal stenosis, treated successfully with a laminectomy and resection.

Intraosseous pseudotumor of the distal radius in a patient with hemophilia: case report.

Hemophilic pseudotumors are rare, particularly when they occur in the distal extremity of an adult patient. We present the case of a 68-year-old man with well-controlled factor VIII deficiency who presented with a lytic lesion of the distal radius that was identified as an intraosseous pseudotumor.

Benign bone tumors--recent developments.

Benign bone tumors frequently pose a diagnostic challenge for general surgical pathologists. Accurate pathologic diagnosis requires careful clinical and radiological correlation. The most significant recent advances in some benign bone tumors have occurred at the molecular and cytogenetic level. The detection of clonal chromosomal aberrations, various specific molecular genetic events, and the description of the bone cell signaling pathways in the field of osteoimmunology have provided a better understanding of the pathophysiology of certain tumors and an important aid in the diagnostic workup and differential diagnosis of some bone lesions demonstrating overlapping clinical and pathologic features. Future directions include prognostic and therapeutic applications of these findings. Newer less invasive therapeutic techniques and medical management have been developed for the treatment of certain benign bone tumors.

Chondroid tenosynovial giant cell tumor: a clinicopathological and immunohistochemical analysis of 5 new cases.

Tenosynovial giant cell tumor (TGCT) arises from the synovium of joints or tendon sheaths. Chondroid metaplasia in TGCT is rare with only 4 well-documented cases reported in the literature. The authors describe the morphological features and immunophenotype of 5 new cases of chondroid TGCT emphasizing a broader range of matrix patterns in these tumors and an expanded immunophenotype, specifically, staining for clusterin and podoplanin which have recently been found to be expressed in conventional TGCTs. Chondroid metaplasia was extensive in 3 cases. Matrix patterns included chondromyxoid, chondro-osseous, hyaline-like, and lace-like calcification similar to that seen in chondroblastoma. The authors conclude that chondroid TGCT is a rare, distinct synovial tumor with a predilection for the temporomandibular joint that has a similar immunophenotype as conventional TGCT. Chondroid metaplasia may be extensive and have a variety of matrix patterns. Chondroid TGCT needs to be distinguished from other chondroid lesions, including chondroblastoma and chondrosarcoma.

Chronic lymphocytic leukemia/small lymphocytic lymphoma presenting as septic arthritis of the shoulder.

We report a case of a 53-year-old man presenting with shoulder pain mimicking septic arthritis. Laboratory findings were atypical. Biopsy performed to assess for possible osteomyelitis demonstrated chronic lymphocytic leukemia/small lymphocytic lymphoma. Intra-articular lymphoma is a rare but important consideration in patients with atypical clinical presentation. Imaging alone may be insufficient to render diagnosis as lymphoma can mimic infection, synovial hypertrophic processes, and depositional arthropathy.

Multifocal renal oncocytoma in a patient with Von Hippel-Lindau mutation.

Von Hippel-Lindau disease (VHL) is a rare genetic disease with a lifetime risk of clear cell renal cell carcinoma in approximately 70% of cases. We present a case of a 63-year-old man with bilateral, multifocal renal masses. Genetic testing results were consistent with a VHL deletion. The patient had no other disease manifestations consistent with VHL. The patient underwent staged bilateral nephron-sparing procedures. Pathology of all renal masses revealed oncocytoma. To our knowledge, we describe the first reported case of multiple renal oncocytomas in a male patient with a germline VHL mutation.

Giant cell tumor of soft tissue with pulmonary metastases: pathologic and cytogenetic study.

Giant cell tumor of soft tissue (GCTST) has gained general acceptance as an uncommon but distinct primary soft tissue tumor since it was first described in 1972. GCTST is predominantly seen in adults and typically shows uniformly dispersed osteoclast-like giant cells admixed with oval to polygonal mononuclear cells. It usually follows a benign clinical course, although the malignant variant has been described in cases in which the mononuclear cells demonstrate obvious dysplastic features. It is still not clear whether the two variants belong to the spectrum of the same tumor. No cytogenetic chromosomal abnormalities have been reported in the literature of GCTST. Interestingly, the osseous counterpart of giant cell tumor, which shares similar histologic features, quite often displays a telomeric association at the cytogenetic level, a finding that has never been reported in GCTST. We report the case of a 12-year-old girl with GCTST of the right leg that metastasized to the lung. Cytogenetic studies from the primary tumor showed the phenomenon of telomeric association involving multiple chromosomes.