Keith Baynes

Fabella fracture with CT imaging: a case report

Fracture of the fabella is rare, may be easily overlooked, and can be a clinically important cause of posterolateral knee pain following traumatic injury or total knee arthroplasty. To date, nine case reports of fabella fracture with radiographic documentation have been reported in the literature. This report documents a 55-year-old male pedestrian who was struck by an automobile and presented with radiographs demonstrating depressed lateral tibial plateau and proximal fibula fractures. Computed tomography (CT) was performed for surgical planning and demonstrated the additional finding of a radiographically occult nondisplaced fabella fracture. To the best of our knowledge, this is the first case in which CT documentation of a fabella fracture is reported. Fracture of the fabella is a rare but important clinical entity which may be overlooked clinically and radiographically. Clinical information can provide a high index of suspicion, and when coupled with radiographic and CT findings, may lead to the correct diagnosis. CT imaging of the knee may confirm a suspected fabella fracture or may help detect a radiographically occult fracture.

Iliotibial band avulsion fracture: a case report with differential diagnosis

Avulsion injuries of the knee are common sequelae of significant trauma given the number of ligamentous and tendinous insertions around the joint. Commonly discussed avulsion fractures of the lateral knee include the Segond fracture of the lateral tibial plateau and the arcuate complex avulsion fracture of the fibular styloid process. A less common avulsion fracture is the iliotibial (IT) band avulsion fracture involving the anterolateral corner of the tibia (Gerdy’s tubercle). It is crucial to identify IT band avulsion fractures because of the frequent associated internal derangements of the knee. This case report describes the imaging of an acute IT band avulsion fracture and compares these findings with other lateral knee avulsion fractures.

Tumor Increase on MRI after Neoadjuvant Treatment is Associated withGreater Pathologic Necrosis and Poor Survival in Patients with Soft TissueSarcoma

Purpose: MRI is often used to evaluate sarcoma response to neoadjuvant treatment, however its role to predict for pathologic response and survival is unclear. Methods and materials: From 2003-2010, 116 patients with STS were treated with neoadjuvant therapy (NAT). 62 patients who had an MRI before and after radiotherapy were analyzed. Radiographic change was correlated with survival and necrosis and fibrosis on pathology. ROC curve analysis was used to assess change in volume that best predicted for pathological necrosis. Results: Median follow-up was 33 months. There was median tumor volume decrease of 15.08 cm3 after treatment. Increase in tumor size and volume was associated with greater necrosis (p<0.03, p=0.001, respectively) and less fibrosis (p<0.001) on pathology. High-grade tumors had more necrosis (p<0.001) and comprised the majority of patients with tumor increases following NAT (88%). Tumor increase of at least 66% predicted for ≥ 70% necrosis with 94% specificity. The 3-year OS was 65% vs. 93% in patients with a decrease in size and volume (p=0.004). In tumors with ≥ 70% necrosis, the 3-year OS was 38% vs. 91% if necrosis was <70% (p<0.001). Conclusions: MR-based tumor increase following NAT was associated with greater % necrosis and less fibrosis on pathology. This tumor increase was more likely high-grade and associated with worse survival.

AIRP Best Cases in Radiologic-Pathologic Correlation: Intraosseous Lipoma

History A 32-year-old woman with a previous diagnosis of human immunodeficiency virus infection presented to her primary care provider in 2010 with a progressively enlarging mass in her proximal right forearm. The patient reported a limited range of motion with decreased extension and, to a lesser extent, decreased flexion because of physical obstruction created by the mass. She denied experiencing pain associated with the mass. The patient reported that the area had been injured when she was assaulted with a board several years before. There was no other pertinent medical history.

Adamantinoma with plasmacytoid features: expanding the spectrum of a diagnostically challenging entity

Adamantinoma is a rare neoplasm that characteristically involves the tibia. In many instances, typical location within the tibia, very slow course, and a typical radiographic appearance can strongly suggest the correct diagnosis. We present a case that has both unusual radiographic findings and uncharacteristic histology. In this case, radiologic imaging showed a poorly defined lytic lesion within the distal, lateral tibia extending to the joint with central necrosis, overlying periosteal reaction and possible tumor spread into soft tissue. The histology of this lesion showed pronounced vascularity and surrounding large neoplastic cells with plasmacytoid morphology. The combination of these features led to an initial misdiagnosis as metastatic carcinoma from unknown primary.