Subperiosteal hematoma of the iliac bone: imaging features of acute and chronic stages with emphasis on pathophysiology

Neoplastic and Non-neoplastic Bone Lesions of the Knee

Numerous anatomical variants are described around the knee, many of which look like bony lesions, so it is important to know them to avoid unnecessary complementary tests and inadequate management. Likewise, several alterations in relation to normal development can also simulate bone lesions.However, numerous pathologic processes frequently affect the knee, including traumatic, inflammatory, infectious, and tumor pathology. Many of these entities show typical radiologic features that facilitate their diagnosis. In other cases, a correct differential diagnosis is necessary for proper clinical management.Despite the availability of increasingly advanced imaging techniques, plain radiography is still the technique of choice in the initial study of many of these pathologies. This article reviews the radiologic characteristics of tumor and nontumor lesions that may appear around the knee to make a correct diagnosis and avoid unnecessary complementary radiologic examinations and inadequate clinical management.

[Radiological diagnosis of apophyseal injuries of the pelvic region]

Avulsion injuries of the pelvis are common sports-related findings in skeletally immature adolescent patients. They usually present as an avulsion of the unfused apophysis, resulting from forced muscular contraction during typical athletic movements or from chronic traction injuries. Acute apophyseal avulsion injuries are usually easily detected with radiography. Occasionally, advanced imaging such as ultrasound or magnetic resonance imaging is required in order to detect or fully assess the extent of injury. Chronic injuries can mimic aggressive entities, such as neoplasms and may thus cause difficulties in differential diagnosis. Profound knowledge of typical locations of apophyseal tendon attachment sites at the osseous pelvis and correct interpretation of imaging findings can facilitate accurate diagnosis. This article discusses the clinical and radiological findings of pelvic apophyseal avulsion injuries in pediatric patients and highlights potential complications and differential diagnoses.

Beyond the abdominal and pelvic cavity: abdominal wall and spinal "Aunt Minnies"

Abdominal wall and spinal soft tissue findings are frequently encountered on CT or MR imaging of the abdomen and pelvis. Many of these entities have specific imaging findings, for which a definitive diagnosis can be made without the need for further work up. These abdominal wall and spinal findings may be diagnostically challenging for sub-specialized abdominal radiologists who are unfamiliar with their appearance and appropriate management. This review article describes and illustrates pathognomonic or characteristic abdominal wall and spinal pathologies, which reside outside the abdominopelvic cavity. The cases selected all have findings that allow a confident diagnosis without further imaging or intervention. The cases presented include myonecrosis, intramuscular abscess, myositis, iliopsoas bursitis, Morel-Lavallée lesion, hydrocele of canal of Nuck, Klippel Trenaunay Weber syndrome, neurofibroma with target sign, perineural cysts, filum terminale lipoma, calvarial bone flap, transverse rectus abdominis muscle (TRAM) flap, liposuction, and hidradenitis suppurativa, among others. Although not all-encompassing, this paper will help abdominal radiologists to accurately diagnose a variety of abdominal and pelvic extra-cavitary soft tissue pathologies by identifying key radiologic findings.

Initial Characterization of Focal Bone Lesions with Conventional Radiographs or Computed Tomography: Diagnostic Performance and Interobserver Agreement Assessment

Objectives: To ascertain the role of CT and conventional radiographs for the initial characterization of focal bone lesions.Methods: Images from 184 patients with confirmed bone tumors included in an ethics committee-approved study were retrospectively evaluated. The reference for benign-malignant distribution was based on histological analysis and long-term follow-up. Radiographs and CT features were analyzed by 2 independent musculoskeletal radiologists blinded to the final diagnosis. Lesion margins, periosteal reaction, cortical lysis, endosteal scalloping, presence of pathologic fracture, and lesion mineralization were evaluated. Results: The benign-malignant distribution in the study population was 68.5-31.5% (126 benign and 58 malignant). In the lesions that could be seen in both radiographs and CT, the performance of these methods for the benign-malignant differentiation was similar (accuracy varying from 72.8% to 76.5%). The interobserver agreement for the overall evaluation of lesion aggressiveness was considerably increased on CT compared to radiographs (Kappa of .63 vs .22). With conventional radiographs, 18 (9.7%) and 20 (10.8%) of the lesions evaluated were not seen respectively by readers 1 and 2. Among these unseen lesions, 50%-61.1% were located in the axial skeleton. Compared to radiographs, the number of lesions with cortical lysis and endosteal scalloping was 26-34% higher with CT. Conclusion: Although radiographs remain the primary imaging tool for lesions in the peripheral skeleton, CT should be performed for axial lesions. CT imaging can assess the extent of perilesional bone lysis more precisely than radiographs with a better evaluation of lesion fracture risk.

Report of a Rare Case of Beta-Thalassemia Major With Subperiosteal Hematomas

Beta-thalassemia represents a range of hemoglobinopathies that are a consequence of an impairment in the synthesis of beta-globin chains. They result in different degrees of hemolysis and ineffective erythropoiesis, depending on the underlying mutations. They can lead to severe complications mainly resulting from anemia. However, there is no bleeding tendency in this disorder, and it is uncommon to see hematoma formation in affected patients.

To our knowledge, subperiosteal hematomas have been rarely described in the context of beta-thalassemia. Herein, we report a unique case of a 19-year-old boy who was diagnosed with transfusion-dependent beta-thalassemia and secondary hemochromatosis and developed atraumatic subperiosteal hematomas along the humerus.

Florid Reactive Periostitis of the Clavicle: A Case Report

Florid reactive periostitis (FRP) is a rare benign fibro-osseous proliferation, occurring mostly in the short tubular bones of hands and rarely in the long tubular bones. We report a surgically confirmed case of FRP involving the clavicle in a 26-year-old male. On MRI scans, a soft tissue mass with T2 high signal intensity was found that originated from the periosteum of the clavicle and included surrounding a periosteal elevation and perilesional soft tissue edema. Strong contrast enhancement was noted inside the mass and along the periosteum involving more than half of the circumference of the clavicle. Serial radiographs revealed a soft tissue mass without mineralization that turned into an ossified mass with a solid periosteal reaction within a month.

Solitary bone tumor imaging reporting and data system (BTI-RADS): initial assessment of a systematic imaging evaluation and comprehensive reporting method

OBJECTIVES

Identify the most pertinent imaging features for solitary bone tumor characterization using a multimodality approach and propose a systematic evaluation system.

METHODS

Data from a prospective trial, including 230 participants with histologically confirmed bone tumors, typical "do not touch" lesions, and stable chondral lesions, were retrospectively evaluated. Clinical data, CT, and MR imaging features were analyzed by a musculoskeletal radiologist blinded to the diagnosis using a structured report. The benign-malignant distribution of lesions bearing each image feature evaluated was compared to the benign-malignant distribution in the study sample. Benign and malignant indicators were identified. Two additional readers with different expertise levels independently evaluated the study sample.

RESULTS

The sample included 140 men and 90 women (mean age 40.7 ± 18.3 years). The global benign-malignant distribution was 67-33%. Seven imaging features reached the criteria for benign indicators with a mean frequency of benignancy of 94%. Six minor malignant indicators were identified with a mean frequency of malignancy of 60.5%. Finally, three major malignant indicators were identified (Lodwick-Madewell grade III, aggressive periosteal reaction, and suspected metastatic disease) with a mean frequency of malignancy of 82.4%. A bone tumor imaging reporting and data system (BTI-RADS) was proposed. The reproducibility of the BTI-RADS was considered fair (kappa = 0.67) with a mean frequency of malignancy in classes I, II, III, and IV of 0%, 2.2%, 20.1%, and 71%, respectively.

CONCLUSION

BTI-RADS is an evidence-based systematic approach to solitary bone tumor characterization with a fair reproducibility, allowing lesion stratification in classes of increasing malignancy frequency.

TRIAL REGISTRATION

Clinical trial number NCT02895633 .

KEY POINTS

• The most pertinent CT and MRI criteria allowing bone tumor characterization were defined and presented. • Lodwick-Madewell grade III, aggressive periosteal reaction, and suspected metastatic disease should be considered major malignant indicators associated with a frequency of malignancy over 75%. • The proposed evidence-based multimodality reporting system stratifies solitary bone tumors in classes with increasing frequencies of malignancy.

Subperiosteal hematoma of the iliac wing presenting with leg weakness in a young adult footballer

We present the case of a 17 year old football player with a 2 week history of left leg weakness and difficulty weight-bearing. Magnetic resonance imaging revealed a well-circumscribed lesion deep to the left iliacus muscle. The patient proceeded to computed tomography-guided biopsy. The likely diagnosis was that of a subperiosteal haematoma of the iliac wing, which was exerting mass effect upon the left femoral nerve resulting in leg pain and weakness. Imaging was repeated at an interval of 1 month, at which time the lesion had almost entirely resolved. Subperiosteal haematoma of the iliac bone is a rare entity but should be considered as a potential diagnosis in young adults, particularly where there is a history of trauma or recent sports injury.

Silent subperiosteal iliac hematoma with bone radiolucency in adolescent male athletes

Background

Subperiosteal hematoma of the iliac bone is reported as a rare disorder that specifically occurs in young patients after obvious trauma. This report presents seven cases of male adolescent athletes with subperiosteal iliac hematoma without blunt trauma that was identified as an incidental radiolucent lesion on the iliac bone mimicking neoplasm. The purpose of this report is to describe clinical features and radiological findings of silent subperiosteal hematoma of the iliac bone.

Subjects and methods

We retrospectively reviewed the clinical data and radiological appearance of 7 patients who presented with subperiosteal hematoma of iliac bone.

Results

All seven patients had no obvious trauma and no serious symptoms. All patients were middle school or high school male students who regularly participated in vigorous sports activity; five soccer players, one baseball catcher, and one basketball player. The X-ray showed radiolucent lesion on the iliac bone. Lens-shaped mass without involvement of psoas muscle with ghost native cortex sign and overlying periosteal calcification on CT scan was characteristic radiological finding on subperiosteal iliac hematoma.

Conclusion

Subperiosteal iliac hematomas can be caused by vigorous sports activity in adolescence. This condition is not always associated with serious symptom. It can be identified as a radiolucent lesion mimicking a neoplasm.

Subperiosteal Hematoma of the Iliac Bone: An Unusual Cause of Acute Hip Pain after a Fall

BACKGROUND Subperiosteal hematoma (SPH) of the iliac bone is an extremely uncommon clinical entity that occurs mostly in young patients with a history of a recent fall or sports-related injury. Patients usually complain of severe hip pain after a fall, mimicking femoral neck fracture. CASE REPORT An 18-year-old female was transported to our hospital complaining of pain in her left hip after falling on her buttocks while engaging in martial arts. Ultrasound of her left iliac region revealed a subperiosteal mass on the internal aspect of the iliac bone lifting the iliac muscle. SPH of the iliac bone was suspected, which was also evident on pelvis and hip magnetic resonance imaging. Repetitive ultrasound did not reveal hematoma expansion. She was discharged from the hospital the next day without femoral neuropathy. CONCLUSIONS Physicians should be aware of our report, which highlights a patient with the rare clinical condition of SPH of the iliac bone occurring immediately after a fall. The differential diagnosis of acute hip pain, which mimics femoral neck fracture, should be considered in young patients. Ultrasound of the iliac region may be useful in detection and further management of SPH of the iliac bone.

Peering beneath the surface: juxtacortical tumors of bone (part II)

Juxtacortical or surface tumors of bone are neoplasms arising from or just outside the cortex, and are composed of different histologic types. Although the imaging appearances of these lesions have similarities to their intramedullary counterparts, their location alters their radiographic and MR characteristics, creating difficulties in diagnosis. Meanwhile, several non-neoplastic lesions, such as stress reaction/stress fracture and indolent infectious processes, compound the differential diagnosis. Neoplastic juxtacortical lesions of bone have been classified into five categories: cartilaginous, fibrous, lipomatous, osseous, and metastatic tumors. Our goal in part two of this review is to illustrate the characteristic radiographic, CT and MR imaging features of various juxtacortical neoplasms, including pathognomonic imaging findings that can aid in diagnosis, and to develop an appropriate differential diagnosis for surface lesions based on imaging characteristics, lesion location and patient age.

MRI findings of post-traumatic subperiosteal hematoma of the iliac bone with resultant femoral nerve palsy in an adolescent boy

Post-traumatic subperiosteal hematoma of the iliac bone may present insidiously without external evidence of bleeding or go undetected in the acute setting. In some cases, the patient may come to medical attention due to femoral nerve palsy rather than hip or groin pain. In this report, we describe a case of femoral nerve palsy caused by acute post-traumatic subperiosteal hematoma of the iliac bone using MRI to highlight the subperiosteal location. Anatomy of the femoral nerve is also discussed.

Bone tumor mimickers: A pictorial essay

Focal lesions in bone are very common and many of these lesions are not bone tumors. These bone tumor mimickers can include numerous normal anatomic variants and non-neoplastic processes. Many of these tumor mimickers can be left alone, while others can be due to a significant disease process. It is important for the radiologist and clinician to be aware of these bone tumor mimickers and understand the characteristic features which allow discrimination between them and true neoplasms in order to avoid unnecessary additional workup. Knowing which lesions to leave alone or which ones require workup can prevent misdiagnosis and reduce patient anxiety.