Snapping scapula syndrome manifests as an audible or palpable crackling during the sliding movements of the scapula over the rib cage, often perceived during physical or professional activities. It can be caused by morphological alteration of the scapula and rib cage, by an imbalance in periscapular musculature forces (dyskinesia), or by neoplasia (bone tumors or soft tissue tumors). In this pictorial essay, we review the main causes of snapping scapula syndrome, exemplified by a collection of didactic cases.

Lipoma arborescens (LA) is an uncommon non-neoplastic disorder that may affect almost any joint, mainly the knee. LA is very rare in the elbow, and there are only a few cases reported in the literature. This study aimed to describe a case of LA in the elbow, presenting with features of a high-grade tumor. The authors report the case of a 51-years-old male who presented to this institution with pain and swelling on the left elbow. The patient had a seven-year history of investigation, with inconclusive diagnosis. Magnetic resonance imaging (MRI) showed an expansive mass with local aggressiveness. Due to these characteristics, it was not possible to discard soft tissue sarcoma at the differential diagnosis. After biopsy and a multidisciplinary team meeting, the authors opted for surgical resection. The final anatomopathological result confirmed the diagnosis of LA. Despite not being a true neoplasm, LA can cause many symptoms and functional impairment of the affected joint. It is important to keep this diagnosis in mind when any expansive mass surrounding a joint is observed.

Objective: To evaluate the incidence and imaging findings of lymphoma after liver transplantation in children. Materials and Methods: The authors reviewed records and imaging studies of children submitted to liver transplantation in the period between 2000 and 2008 in a single institution. Results: Among 241 children submitted to liver transplantation, with a mean follow-up period of 41.4 ± 26.4 months, 16 (6.6%) had lymphoma. The mean age of the patients who developed lymphoma at the moment of transplantation was lower than in children who did not develop malignancy (23.9 ± 18.9 versus 38.0 ± 48.9 months; p = 0.02). The time interval between liver transplantation and the diagnosis of lymphoma ranged from 6 to 103 months. Clinical and radiological presentation was variable and the abdomen was the most common location of the tumor (n = 13; 81.3%), followed by chest and head and neck (n = 4; 25.0% each). Imaging findings included adenopathy, mediastinal, pulmonary and mesenteric masses, bowel wall thickening and hepatic and renal nodules. Four children (25.0%) died because of complications of lymphoma. Conclusion: Lymphomas are relatively uncommon and potentially fatal complications that may occur any time after pediatric liver transplantation, presenting different clinical and imaging findings. Keywords: Lymphoma; Hepatic transplantation; Pediatrics; Imaging diagnosis; Postoperative complications.Objetivo: Avaliar a incidência e os aspectos de imagem do linfoma pós-transplante hepático em crianças. Materiais e Métodos: Foram revisados os prontuários e exames de imagem de crianças submetidas a transplante hepático entre 2000 e 2008 em uma única instituição. Resultados: De 241 crianças submetidas a transplante hepático, com seguimento médio de 41,4 ± 26,4 meses, 16 (6,6%) tiveram linfoma. A média de idade no transplante hepático das crianças que desenvolveram linfoma foi inferior à das crianças que não desenvolveram (23,9 ± 18,9 vs. 38,0 ± 48,9 meses; p = 0,02). O tempo entre o transplante e o desenvolvimento do linfoma variou de 6 a 103 meses. A apresentação clínica e radiológica foi variável e a localização mais comum do tumor foi no abdome (n = 13; 81,3%), seguida de tórax e cabeça e pescoço (n = 4; 25,0% cada). Os achados de imagem incluíram: linfonodomegalias, massas mediastinais, pulmonares e mesentéricas, espessamento parietal de alças intestinais e nódulos hepáticos e renais. Quatro crianças (25,0%) faleceram devido a complicações do linfoma. Conclusão: Linfomas são complicações relativamente incomuns e potencialmente fatais que podem acontecer a qualquer momento após o transplante hepático em crianças, e que têm diversas apresentações clínicas e de imagem. Unitermos: Linfoma; Transplante hepático; Pediatria; Diagnóstico por imagem; Complicações pós-operatórias. AbstractResumo

Primary bone lymphoma is a rare neoplasm that can initially present as local pain, a palpable mass, and pathologic fracture. It can also be discovered as an incidental finding on an imaging examination. It is defined as a bone marrow tumor with no involvement of other sites, lasting at least six months. The diagnosis is confirmed by biopsy and immunohistochemical analysis. Although the imaging characteristics are nonspecific, there are certain findings that, when correlated with clinical and epidemiological aspects, can increase the level of suspicion of primary bone lymphoma. The classic imaging aspect is a bone lesion with a soft-tissue component that preserves the cortical layer more than would be expected given the invasive nature of the lesion. Magnetic resonance imaging is the best imaging method to evaluate the extent of involvement of adjacent compartments, whereas computed tomography depicts the cortical layer in greater detail, as well as being an important tool for biopsy guidance. Other imaging modalities are also discussed, such as X-ray, ultrasound, bone scintigraphy, and positron emission tomography/computed tomography. The aim of this paper is to describe the most common findings obtained with the various imaging methods used in patients with a confirmed diagnosis of primary bone lymphoma.

Primary osseous angiosarcoma is a rare entity with variable biological behavior and poor prognosis. Little is known about the oncologic treatment and its etiology is still unknown. This study presents a case of lytic lesion in the right femur with dissemination to other bones, such as the vertebral column and skull, and to the lungs and central nervous system. Orthopedic surgery was performed in order to improve quality of life. Surgical specimen confirmed the diagnosis of high-grade malignant osseous angiosarcoma. Despite oncologic and orthopedic treatment, the patient had rapid and aggressive progression with a poor outcome.