Primary B cell lymphoma of the patella presenting as anterior knee pain: A case report.

Case: A 76-year-old female with a history of multiple falls on the patella presented with worsening knee pain, swelling, and reduced range of motion. Radiographs revealed tricompartmental osteoarthritis and subtle erosion of the posterior cortex of the patella that was missed by the referring orthopedist and radiologist. Her persistent pain prompted an MRI, revealing a mass later confirmed to be primary diffuse large B-cell lymphoma of the patella after biopsy and appropriate metastatic workup. Conclusion: Primary B-cell patellar lymphoma is a rarely described cause of knee pain requiring broad differential diagnosis and multidisciplinary workup in order to avoid erroneous treatment and ensure prompt oncologic treatment.

Computed Tomography Findings in Vernix Caseosa Peritonitis.

INTRODUCTION: Vernix caseosa peritonitis (VCP) is a rare peripartum complication secondary to the introduction of fetal vernix into the maternal peritoneal cavity. Vernix caseosa peritonitis typically manifests a few hours to days after a cesarian section and is often initially misdiagnosed as a more common disease process resulting in delayed diagnosis. We report the computed tomography (CT) findings in 2 patients with VCP and reviewed the previously reported CT findings of VCP. CASES: Two patients, aged 17 and 24 years, presented with signs and symptoms of peritonitis within days of undergoing a cesarian section. In both cases, CT scans of the abdomen and pelvis demonstrated ascites and multiple small, well-defined, peripherally enhancing, cystic peritoneal nodules which were most prominent around the liver and became larger and more numerous over time. Antibiotic therapy was not effective, subsequent laparoscopic peritoneal biopsy demonstrated VCP, and patients were successfully treated with lavage and the addition of intravenous steroids. CONCLUSIONS: Vernix caseosa peritonitis is an underrecognized disorder that is most often mistaken for other more common causes of peritonitis. In the setting of peripartum peritonitis, the CT findings of ascites with multiple small, well-defined, peripherally enhancing, cystic peritoneal nodules, especially adjacent to the liver, which grow in size and number strongly suggests VCP.

The Use of Periareolar Topical Lidocaine Jelly After Needle Localization May Reduce Pain of Subsequent Lymphoscintigraphy.

Purpose Technetium Tc-99m sulfur colloid (99mTc-SC) breast lymphoscintigraphy is commonly performed to identify the sentinel lymph node (SLN) in patients diagnosed with breast carcinoma undergoing lumpectomy. The purpose of this report is to describe how the use of 2% topical lidocaine jelly immediately after the completion of needle localization and prior to scintigraphy may substantially reduce pain associated with the injection of 99mTc-SC. Materials and methods This was a quality improvement project. Patients were asked to score the severity of pain associated with the periareolar 99mTc-SC injections for sentinel node lymphoscintigraphy. In order to decrease the discomfort, topical lidocaine was applied to the periareolar skin after the completion of the needle localization, but prior to transferring the patient from the mammography room to the nuclear medicine department for the 99mTc-SC injections. At the time of 99mTc-SC injection, patients were asked to score the pain of injection from 0 (none) to 10 (worst). Results The average pain score of the women who did not receive topical lidocaine jelly was 8 (range: 5-9). In the 10 women who received topical lidocaine jelly after needle localization, the average pain score was 2.5 (range: 1-5). Interestingly, the pain score for women who discussed the possible use of lidocaine jelly with the radiologists but still did not receive topical lidocaine jelly was also low at 6.5. For patients who received the lidocaine jelly only five minutes prior to injection, the average pain score was 6. Conclusion The application of lidocaine jelly after the conclusion of needle localization, with a 15-40-minute delay prior to periareolar injections with 99mTc-SC for sentinel node lymphoscintigraphy, appears to substantially reduce the pain associated with the injection of 99mTc-SC.

Xanthogranulomatous pancreatitis: A review of the imaging characteristics of this rare and often misdiagnosed lesion of the pancreas.

Xanthogranulomatous pancreatitis (XGP) is an extremely rare cause of a cystic pancreatic mass. The pathophysiology of this process is not entirely clear but likely results from a combination of duct obstruction, infection, and repeated hemorrhage. It is difficult to differentiate this inflammatory lesion from a cystic neoplasm and, therefore, in the majority of cases XGP is misdiagnosed as a neoplasm on preoperative imaging. In this report, we describe a case of XGP, the imaging characteristics of XGP, and a differential diagnosis for a cystic pancreatic lesion.

Imaging Surveillance in Patients After a Benign Fine-Needle Aspiration Biopsy of the Thyroid: Associated Cost and Incidence of Subsequent Cancer.

OBJECTIVE: The objective of our study was to determine patterns and cost of imaging tumor surveillance in patients after a benign fine-needle aspiration (FNA) biopsy of the thyroid in a large teaching hospital as well as the rate of subsequent cancer detection. MATERIALS AND METHODS: This cohort study was approved by the appropriate institutional review board and complied with HIPAA. All patients who had a benign thyroid FNA biopsy between January 1, 1999, and December 31, 2003, were identified from an institutional pathology database. We gathered information from electronic medical records on imaging tumor surveillance and subsequent cancer detection. Cost was determined using the facility total relative value unit and the 2014 Hospital Outpatient Prospective Payment System conversion factor. RESULTS: Between January 1, 1999, and December 31, 2003, 1685 patients had a benign thyroid FNA biopsy, 800 (47.5%) of whom underwent follow-up imaging. These patients underwent 2223 thyroid ultrasound examinations, 606 ultrasound-guided thyroid FNA biopsies, 78 thyroid scintigraphy examinations, 168 neck CTs, and 53 neck MRIs at a cost of $529,874, $176,157, $39,622, $80,580, and $53,114, respectively, for a total cost of $879,347 or $1099 per patient. The mean length of follow-up was 7.3 years, during which time 19 (2.4%) patients were diagnosed with thyroid cancer at a cost of $46,281 per cancer. Seventeen (89.5%) were diagnosed with papillary carcinoma and two (10.5%) with Hurthle cell carcinoma. CONCLUSION: Over a 5-year period, about half of the patients who had a benign thyroid FNA biopsy underwent follow-up imaging at considerable cost with a small rate of subsequent malignancy.

Transient washout of hepatic hemangiomas: Potential pitfall mimicking malignancy.

Hemangiomas are the most common tumor of the liver and distinguishing them from malignancy is important. This is a report of 3 hemangiomas in 2 patients that exhibit transient washout of gadoxetate disodium (Eovist), relative to blood pool and liver parenchyma, a characteristic that is used to diagnose hepatocellular carcinoma in at-risk patients. It is important to recognize that high-flow hemangiomas can exhibit transient washout when using a small volume of injected contrast agent. This finding is unlikely to be present on CT examinations because of the larger volume of contrast administered.

Hepatocellular carcinoma after locoregional therapy: Magnetic resonance imaging findings in falsely negative exams.

AIM: To elucidate causes for false negative magnetic resonance imaging (MRI) exams by identifying imaging characteristics that predict viable hepatocellular carcinoma (HCC) in lesions previously treated with locoregional therapy when obvious findings of recurrence are absent. METHODS: This retrospective institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study included patients who underwent liver transplantation at our center between 1/1/2000 and 12/31/2012 after being treated for HCC with locoregional therapy. All selected patients had a contrast-enhanced MRI after locoregional therapy within 90 d of transplant that was prospectively interpreted as without evidence of residual or recurrent tumor. Retrospectively, 2 radiologists, blinded to clinical and pathological data, independently reviewed the pre-transplant MRIs for 7 imaging features. Liver explant histopathology provided the reference standard, with clinically significant tumor defined as viable tumor ≥ 1.0 cm in maximum dimension. Fisher's exact test was first performed to identify significant imaging features. RESULTS: Inclusion criteria selected for 42 patients with 65 treated lesions. Fourteen of 42 patients (33%) and 16 of 65 treated lesions (25%) had clinically significant viable tumor on explant histology. None of the 7 imaging findings examined could reliably and reproducibly determine which treated lesion had viable tumor when the exam had been prospectively read as without evidence of viable HCC. CONCLUSION: After locoregional therapy some treated lesions that do not demonstrate any MRI evidence of HCC will contain viable tumor. As such even patients with a negative MRI following treatment should receive regular short-term imaging surveillance because some have occult viable tumor. The possibility of occult tumor should be a consideration when contemplating any action which might delay liver transplant.

Differentiation of lipid-poor adrenal adenomas from non-adenomas with magnetic resonance imaging: Utility of dynamic, contrast enhancement and single-shot T2-weighted sequences.

PURPOSE: To evaluate the utility of dynamic, contrast-enhanced magnetic resonance imaging (MRI) in combination with single-shot T2-weighted (ssT2) sequences in the differentiation of lipid-poor adrenal adenomas from non-adenomas. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board and is HIPAA compliant. Between January 2007 and December 2010, 46 patients with MRI demonstrating a lipid-poor adrenal lesion who underwent either surgical resection or a minimum of 24 months of imaging follow-up were identified retrospectively. All images were retrospectively reviewed in blinded fashion by two radiologists. Each adrenal lesion was categorized by dynamic enhancement features and qualitative signal on ssT2 images and was categorized as an adenoma if it demonstrated homogenous enhancement in the arterial phase, washout with capsule enhancement in the delayed phase, and T2 signal isointense to normal adrenal tissue. Any lesion that did not fulfill all the criteria was classified as a non-adenoma. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for characterization of adenoma were calculated for each reader with 95% confidence intervals. A κ test assessed level of agreement between readers. RESULTS: Application of our criteria lead to an MRI diagnosis of lipid-poor adrenal adenoma with a sensitivity of 84.2-89.5% (16/19-17/19), specificity of 96.3% (26/27), positive predictive value of 94.1-94.4% (16/17-17/18), negative predictive value of 89.7-92.9% (26/29-26/28), and accuracy of 91.3-93.5% (42/46-43/46). Agreement between the two readers showed substantial κ agreement for the differentiation of adenoma from non-adenoma. CONCLUSIONS: Dynamic, contrast-enhanced T1-weighted three-dimensional gradient echo sequences in combination with ssT2 images can accurately differentiate lipid-poor adrenal adenomas from non-adenomas.

Hepatocellular carcinoma lesion characterization: single-institution clinical performance review of multiphase gadolinium-enhanced MR imaging--comparison to prior same-center results after MR systems improvements.

PURPOSE: To measure diagnostic performance in the detection of hepatocellular carcinoma (HCC) by using the most recent technology and multiphase gadolinium-enhanced magnetic resonance (MR) imaging and to compare with earlier results at the same institution. MATERIALS AND METHODS: This retrospective study was institutional review board approved and HIPAA compliant. Informed consent was obtained. Between January 2008 and April 2010, 101 patients underwent liver transplantation and pretransplantation abdominal MR imaging within 90 days. Prospective image interpretations from the clinical record were reviewed for documentation of HCC, including size, number, and location. Liver explant histologic examination provided the reference standard for lesion analysis and was performed in axial gross slices in conjunction with the MR imaging report for direct comparison. Tumors were categorized according to size (≥ 2 cm or <2 cm), and MR imaging detection sensitivity, specificity, predictive values, and accuracy were calculated according to category. The Fisher exact test was used to compare results from this study against prior reported results. RESULTS: Thirty-five (34.7%) of 101 patients had HCC at explant analysis. Patient-based analysis of all lesions showed a sensitivity and specificity of 97.1% (34 of 35) and 100% (66 of 66), respectively. For lesions 2 cm or larger, MR imaging had a sensitivity and specificity of 100% (23 of 23) and 100% (78 of 78), respectively. For lesions smaller than 2 cm, MR imaging had a sensitivity and specificity of 82.6% (19 of 23) and 100% (78 of 78), respectively. Lesion-based sensitivity for all tumors was 91.4% (53 of 58) in the current study, compared with 77.8% in 2007 (P = .07). For lesions smaller than 2 cm, the sensitivity was 87.5% (28 of 32) in the current study, compared with 55.6% previously (P = .02). CONCLUSION: MR imaging remains a highly accurate diagnostic method for the preoperative evaluation of HCC, and detection of small (<2 cm) tumors has been significantly improved compared with that of earlier studies.