Acro-osteolysis: imaging, differential diagnosis, and disposition review.

Acro-osteolysis is the osseous destruction of the hand or foot distal phalanges. The categories of the disease include terminal tuft, midshaft, or mixed types. Recognition of acro-osteolysis is straightforward on radiographs, but providing an accurate differential diagnosis and appropriately recommending advanced imaging or invasive tissue diagnosis can be more elusive. A radiologist's ability to provide advanced assessment can greatly aid clinicians in expedient diagnosis and management of the array of diseases presenting with acro-osteolysis.

MRI Does Not Reliably Detect Kaplan Fiber Injury In Skeletally Immature Patients with an Acute ACL Tear.

Background: To our knowledge, there have been no previous efforts to evaluate the prevalence of Kaplan fiber (KF) injury in skeletally immature patients with an acute anterior cruciate ligament (ACL) tear on magnetic resonance imaging (MRI) nor has there been any comparison of the reliability of previously described KF diagnostic criteria in this cohort. Purpose: To define the prevalence of KF injury in the setting of acute ACL tears using MRI performed within 90 days of injury among skeletally immature patients, and to compare the reliability of MRI in detecting KF injuries using 2 previously described diagnostic criteria. Study Design: Cohort study; Level of evidence, 3. Methods: Skeletally immature patients with an acute ACL tear confirmed using MRI within 90 days of injury were assessed. Two fellowship-trained musculoskeletal radiologists independently interpreted each MRI scan twice. KF injury was first assessed using the Van Dyck scheme (grade 0, normal; grade 1, periligamentous; grade 2, partial tear; and grade 3, complete tear). MRI scans were then reviewed again using the KF injury criteria proposed by Batty. Discrepancies in KF injury schemes were adjudicated by a third musculoskeletal radiologist. Interrater agreement for both methods was determined using Cohen κ. Results: Included were 45 patients (33 male, 12 female) with a mean age of 13.2 ± 1.6 years. KF injuries were identified in 17 of 45 (37.7%) knees of using the traditional Van Dyck grading scheme (interrater agreement κ = 0.40). The Batty diagnostic criteria identified KF injury in 5 of 45 (11.1%) (interrater agreement κ = 0.45); 17 (37.8%) MRI scans required a third reviewer adjudication for the Van Dyck scheme, while 4 (8.9%) required a third reviewer using the Batty criteria. Conclusion: The Batty diagnostic criteria detected a lower KF injury prevalence than previously reported in the adult population, while the Van Dyck prevalence was similar to rates in adult populations. Both grading criteria had poor interrater reliability in diagnosing a KF injury.

Nerve Sheath Myxoma in the Lower Extremity: A Rare Case with Description of Magnetic Resonance Imaging and Sonographic Findings.

BACKGROUND This report is of a nerve sheath myxoma presenting as a slow-growing mass in the back of the left ankle of a 36-year-old man that was investigated by ultrasound and magnetic resonance imaging (MRI) before the diagnosis was confirmed by histopathology. CASE REPORT We report a nerve sheath myxoma of the ankle in a 36-year-old man. The palpable abnormality was falsely assumed to be a ganglion cyst prior to advanced imaging. Magnetic resonance imaging demonstrated a lobular mass with high T2 and intermediate T1 signal as well as moderate enhancement. T2 sequences also demonstrated distinctive internal septae. These internal septae were also noted on sonographic evaluation prior to biopsy. The patient was treated with surgical excision, and pathologic analysis showed myxoid nodules with loose arrangements of spindled cells separated by fibrous septae. S-100 protein and glial fibrillary acidic protein positivity by immunohistochemistry staining was demonstrated. Follow-up imaging at 12 months showed no evidence of tumor recurrence. CONCLUSIONS This case highlights that while nerve sheath myxomas are rare tumors, they should be considered in cases of cutaneous soft-tissue masses with myxoid imaging features. Ultrasound and magnetic resonance imaging features of thin internal septae may be present and correspond well with the unique histopathological characteristics of these lesions. This report shows the importance of imaging of peripheral soft-tissue masses, including ultrasound and MRI, which can identify localized and benign features and the solid, cystic, and myxoid areas, which were characteristic in this case of benign nerve sheath myxoma.

Desmoid-type fibromatosis of the lower extremity: A unique case of complete lesion resolution following core needle biopsy.

Desmoid-type fibromatosis (DF) is a rare neoplasm characterized by fibroblastic and myofibroblastic proliferation. While characterized as a benign lesion that does not metastasize, desmoid-type fibromatosis exhibits a wide range of behavior from aggressive local tissue invasion and post-surgical recurrence to spontaneous regression. Tumor regression can occur following systemic medical therapy or rarely may occur in the absence of therapy. We present a case of a 50-year-old female with a left thigh vastus medialis intramuscular mass which underwent imaging work-up and subsequent core needle ultrasound-guided biopsy showing results of desmoid-type fibromatosis. Following biopsy, the tumor showed prompt, complete regression with complete MRI resolution 2 months following biopsy. The patient showed no evidence of disease recurrence out to one year on MRI surveillance. This case report will discuss desmoid-type fibromatosis imaging features, treatment strategies, spectrum of disease behavior, and atypical behavior such as the spontaneous tumor regression as seen in this case report. To our knowledge there have been no reported cases of DF spontaneous regression 2 months following a core needle biopsy. Understanding the variable behavior of desmoid-type fibromatosis can assist the radiologist in guiding management of these lesions with the goal of optimizing clinical outcomes and preventing unnecessary aggressive treatments for stable or regressing disease.

Sigmoid cancer mimicking ovarian echotexture on transvaginal ultrasound: Case report with literature review.

Ultrasound is a first line imaging modality for the evaluation of female pelvic pain. Pelvic pain constitutes one of the most common reasons for presentation to the emergency department with increasing use of point of care ultrasound. Infrequently, point of care or formal ultrasound evaluation may lead to misdiagnosis of extraovarian disease. This can have serious consequences, especially if an extraovarian malignancy is mistaken for a normal ovary or an ovary with a benign process. We present a case of a 41-year-old female who presented to the emergency department for a chief complaint of pelvic pain and vaginal bleeding. Transvaginal ultrasound demonstrated a left adnexal mass, later characterized as a sigmoid colon cancer on MRI and pathology, simulating ovarian echotexture with peripheral hypoechoic components resembling follicles. This article will review the literature of various cases of extraovarian pathology misidentified as ovarian processes and highlight the importance of considering these extraovarian mimickers to prevent potential morbidity and mortality of a missed diagnosis.

Diffuse skeletal muscle extramedullary plasmacytomas: a rare case and review of the literature.

Extramedullary plasmacytomas are rare neoplasms arising from proliferations of monoclonal plasma cells. In primary form, these malignancies occur without other sites of plasma cell disease. Secondary extramedullary plasmacytomas occur in association with multiple myeloma and may be discovered during initial intramedullary disease or may occur during multiple myeloma relapse. In very rare instances, secondary extramedullary plasmacytomas have multifocal skeletal muscle involvement. We present a case of multifocal skeletal muscle plasmacytomas in a 58-year-old man with shoulder-reduced range of motion, pain, and a history of previously treated multiple myeloma. To our knowledge, the patient's unique relapse presentation of torso and shoulder soft tissue masses and the vast extent of skeletal muscle involvement are unique to cases in the current literature. This case also has MRI findings of a muscular plasmacytoma with internal hemorrhage which has not been previously reported. This case report will review imaging features and clinical presentations of intramuscular extramedullary plasmacytomas. Since imaging surveillance for multiple myeloma relapse is commonly performed, radiologists should be aware of these uncommon relapsing features including multifocal intramuscular masses which may contain internal hemorrhage.

Osteoid Osteoma at the Lesser Trochanter: A Lesson in Mimicry.

A 16-year-old female soccer player presented with an eight-month-old, insidious right-hip pain. The imaging workup demonstrated a cortically based lytic lesion at the level of the lesser trochanter with surrounding sclerosis, adjacent periosteal reaction, and a small soft-tissue mass. A biopsy revealed findings related to an osteoid-forming lesion with features of nuclear atypia. The patient's pathology referral returned a diagnosis of osteoid osteoma, and she was treated with CT-guided cryoablation. She had an excellent response and returned to full activities through nearly two years of surveillance. In similar patients approaching skeletal maturity, the differential diagnosis for bone lesions involving the lesser trochanter ranges from post-traumatic to primary oncologic processes. Given the implications of a missed malignancy, vigilance is required when treating young and active patients.

Traumatic knee injury: correlation of radiographic effusion size with the presence of internal derangement on magnetic resonance imaging.

PURPOSE: Traumatic knee injury is a common clinical presentation. However, knee internal derangement often goes undiagnosed on physical exam. The authors hypothesize that patients with suprapatellar joint effusion greater than 10 mm anteroposterior diameter on lateral radiograph have a high likelihood of knee internal derangement on magnetic resonance imaging. MATERIALS AND METHODS: A retrospective review of knee radiographs and magnetic resonance imaging in 198 patients age 18-40 years with acute knee injury was performed. Suprapatellar effusion diameter on lateral radiography was correlated to the presence of internal derangement on magnetic resonance imaging. Magnetic resonance imaging anteroposterior effusion size at four locations was correlated to radiographic suprapatellar effusion measurements. RESULTS: Logistic regression showed a positive correlation between radiographic effusion size and the presence of internal derangement on magnetic resonance exams (p value < 0.001). Radiographic effusion > 10 mm was established as a positive test, yielding test sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 55, 96, 93, 71, and 77%, respectively. Statistical analysis showed the radiographic anteroposterior effusion diameter most closely approximated the magnetic resonance effusion diameter at the lateral patellofemoral recess. CONCLUSIONS: This study shows that knee radiography is a highly specific screening test for internal derangement in patients less than 40 years old with acute knee injury. In this patient population, knee effusion > 10 mm on lateral radiograph should prompt consideration for knee magnetic resonance examination. Adopting this approach as a clinical guideline has the potential to decrease delayed diagnosis, improve patient outcomes, and decrease cost-associated disability.

Subtle radiographic signs of hamate body fracture: a diagnosis not to miss in the emergency department.

Hamate fractures are estimated to represent 1.7% of all carpal fractures and can occur at the hamulus (hook) or hamate body depending on mechanism of injury. Fractures of the hamate body can be exceedingly difficult to identify on standard wrist and hand radiographs in the emergency department. If the diagnosis is missed in the emergency department, orthopedic referral is often delayed. This can result in lasting functional disability for the patient, as these fractures have a propensity to destabilize the fourth and fifth carpometacarpal (CMC) joints. In this pictorial essay, we present six radiographic signs indicative of hamate body fracture with computed tomography (CT) imaging correlation. Injury mechanism and fracture classification schemes are portrayed to aid in the understanding of these injuries. Once radiographs raise suspicion for a hamate body fracture, further characterization with CT and orthopedic referral is paramount. Goals of orthopedic management include reestablishment of the fourth and fifth CMC articular surface, stabilization of the CMC joints, and appropriate treatment of concomitant soft tissue injury.

Peroneus Brevis Tendon Variant Insertion on the Calcaneus.

Insertion of the peroneus brevis tendon normally occurs at the lateral aspect of the fifth metatarsal base. However, there is new evidence that congenital variant insertion of the tendon on the calcaneal peroneal tubercle occurs in a small segment of the population. We report a case of 24-year old male presenting with non-traumatic ankle pain who underwent ankle magnetic resonance imaging. Imaging demonstrated insertion of the peroneus brevis tendon on the calcaneal peroneal tubercle with absence of the tendon distal to the calcaneus. Furthermore, in reviewing 200 consecutive ankle magnetic resonance examinations, the authors discovered one additional case of this variant. We discuss the magnetic resonance imaging characteristics of this anatomic variant, the implications for clinical management, and review the literature on peroneal anatomic variations.

CT radiation dose: current controversies and dose reduction strategies.

OBJECTIVE: The purpose of this article is to use clinical scenarios to explore aspects of ionizing radiation imparted to patients undergoing CT examinations. Examination appropriateness, effective doses, cancer risks, and pertinent dose reduction strategies are reviewed. CONCLUSION: CT accounts for the majority of radiation exposure related to medical imaging. Medical professionals should have a working knowledge of the benefits and risks of medical radiation and an understanding of strategies for reducing CT radiation dose.

Case report of xanthogranulomatous cholecystitis, review of its sonographic and magnetic resonance findings, and distinction from other gallbladder pathology.

A case of xanthogranulomatous cholecystitis is presented with a brief review of its sonographic and magnetic resonance features. These imaging features are also compared to those seen in gallbladder adenomyomatosis and gallbladder carcinoma. While there are many overlapping imaging findings in these entities, it is important to recognize distinguishing characteristics so a correct surgical approach is chosen. Laparoscopic cholecystectomy attempted with existing xanthogranulomatous cholecystitis has an increased surgical complication rate compared to open cholecystectomy and often necessitates intraoperative conversion to open cholecystectomy.