Ultrasonido en tumores óseos como hallazgo inesperado: Elementos de sospecha y caracterización

Abstract

Introduction. The swelling of the soft tissues can be studied with a variety of techniques, amongst which the emphasis is on high resolution ultrasound (US) for its high availability. Bone tumors are a very rare cause of increased volume in soft tissue. Before the ultrasound finding of a bone tumor it is important to try to specify their nature to determine the need for additional studies. Objective. To present an ultrasound schema that allows for a better diagnostic approach to the unusual finding of a bone tumor. Method. Retrospective study. All soft tissue ultrasound performed at our institution over a period of five years (2009-2013), were reviewed. Two expert radiologists consensually analyzed the US which demonstrated a bone tumor underlying an increased volume of soft tissue. The series consists of 30 ultrasonographic studies. Results. In all of the cases, the US showed a dermoepidermal complex, of the subcutaneous tissue and the normal aponeurosis plane. In the deep planes altered cortical bone was identified. Complementary studies and in some cases biopsies, allowed us to determine the nature of the evaluated lesions. They corresponded to osteomas, osteochondromas, subungual exostoses, bone hemangioma, brown tumor, enchondroma and bone metastases. It was possible to identify certain ultrasound patterns of the soft tissue bone lesions. We described three patterns which we named: Type I - Raised hyperechoic lesion with acoustic shadowing; Type II - Hypoechoic lesion: IIa, without bone destruction and IIb: with cortical destruction and soft tissue mass; Type III - Presence of irregular periostitis and soft tissue mass. Conclusions. It was possible to recognize an ultrasound pattern of tumors of bone origin. Most cases are benign lesions (osteomas and subungual exostoses) and are presented as Type I. In contrast the Type III pattern suggests aggressiveness and is present in metastatic lesions. In the hypoechoic lesions, the cortical destruction and soft tissue mass suggest aggressiveness (IIb) however the absence of bone destruction and soft tissue mass rather suggests benign processes. These patterns can be useful for radiologists, to make a better diagnostic approach.