Case 261: Thymoma Embedded in Thymus with Pleural Implant in Myasthenia Gravis Lambert-Eaton Overlap Syndrome.

History A 29-year-old woman presented with a 6-month history of progressive general fatigue, fluctuating limb weakness, and difficulty climbing stairs. She initially experienced occasional episodes of transient diplopia that developed while reading in the evening. She subsequently started to experience dry eyes and mouth, difficulty chewing, and mild dysphagia that worsened throughout the day. Her medical history included hypothyroidism from Hashimoto thyroiditis and pneumonia with left pleural effusion. She had no smoking history, and her body mass index was normal (23.8 kg/m2). No medication use was reported at admission. Physical examination revealed mild bilateral ptosis, reduced muscle tone and strength that worsened in proximal leg muscles, and decreased deep tendon reflexes. An edrophonium test revealed improvement in muscle strength and eyelid ptosis. Repetitive nerve stimulation revealed low amplitude of compound muscle action potential at rest (0.21 mV), with a marked increase (700%; normal increase, <60%) at high-rate stimulation (50 Hz). Laboratory work-up was unremarkable except for detection of acetylcholine receptor antibodies in the serum (21.30 nmol/L) and P/Q-type voltage-gated calcium channel antibodies (220 pmol/L). Recent MRI of the brain and spine at an outside hospital showed no abnormal findings. At admission, the patient underwent CT of the chest, abdomen, and pelvis followed by thoracic MRI to further evaluate CT findings.

Case 261.

History A 29-year-old woman presented with a 6-month history of progressive general fatigue, fluctuating limb weakness, and difficulty climbing stairs. She initially experienced occasional episodes of transient diplopia that developed while reading in the evening. She subsequently started to experience dry eyes and mouth, difficulty chewing, and mild dysphagia that worsened throughout the day. Her medical history included hypothyroidism from Hashimoto thyroiditis and pneumonia with left pleural effusion. She had no smoking history, and her body mass index was normal (23.8 kg/m2). No medication use was reported at admission. Physical examination revealed mild bilateral ptosis, reduced muscle tone and strength that worsened in proximal leg muscles, and decreased deep tendon reflexes. An edrophonium test revealed improvement in muscle strength and eyelid ptosis. Repetitive nerve stimulation revealed low amplitude of compound muscle action potential at rest (0.21 mV), with a marked increase (700%; normal increase, <60%) at high-rate stimulation (50 Hz). Laboratory work-up was unremarkable except for detection of acetylcholine receptor antibodies in the serum (21.30 nmol/L) and P/Q-type voltage-gated calcium channel antibodies (220 pmol/L). Recent MRI of the brain and spine at an outside hospital showed no abnormal findings. At admission, the patient underwent CT of the chest, abdomen, and pelvis ( Fig 1 ) followed by thoracic MRI ( Figs 2 , 3 ) to further evaluate CT findings. [Figure: see text][Figure: see text][Figure: see text][Figure: see text][Figure: see text][Figure: see text][Figure: see text][Figure: see text].

Differentiation of rebound and lymphoid thymic hyperplasia from anterior mediastinal tumors with dual-echo chemical-shift MR imaging in adulthood: reliability of the chemical-shift ratio and signal intensity index.

PURPOSE: To prospectively evaluate (a) effectiveness and limits of dual-echo chemical-shift magnetic resonance (MR) imaging for distinguishing hyperplastic thymus from anterior mediastinal tumors in adulthood by using chemical-shift ratio ( CSR chemical-shift ratio ) and signal intensity index ( SII signal intensity index ), with proposal of optimal threshold value for each, and (b) whether age affects these indexes. MATERIALS AND METHODS: Study was institutional review board approved, with informed consent obtained. Ninety-two subjects (53 men, 39 women; age range, 18-84 years) were divided into a rebound and lymphoid hyperplasia group (group A, 30 patients) and a tumor group (group B, 62 patients). MR images were assessed; interrater reliability was evaluated. Differences in CSR chemical-shift ratio and SII signal intensity index were tested with the Mann-Whitney U test and the Kruskal-Wallis test. Discrimination abilities of CSR chemical-shift ratio and SII signal intensity index were evaluated with logistic regression models, and optimal cutoff points were proposed. Quantitative parameters were correlated with age by using Pearson correlation coefficients. RESULTS: Interreader agreement was excellent (intraclass correlation coefficient: CSR chemical-shift ratio , 0.893; SII signal intensity index , 0.898). Mean CSR chemical-shift ratio and SII signal intensity index ± standard deviation were 0.545 ± 0.162 and 46.29% ± 18.41 for group A and 1.045 ± 0.094 and -0.06% ± 4.89 for group B, respectively, with significant differences for both indexes between groups (P < .0001). No overlap was found for SII signal intensity index between groups; CSR chemical-shift ratio values overlapped in a few younger adults. Distinguishing hyperplastic thymus from tumors was better with SII signal intensity index than CSR chemical-shift ratio . Respective sensitivity, specificity, and cutoff points were 100%, 100%, and 8.92% for SII signal intensity index and 100%, 96.7%, and 0.849 for CSR chemical-shift ratio . Significant correlation was found for CSR chemical-shift ratio (r = -0.761) and SII signal intensity index (r = 0.821) with age in group A (P < .001). For group B, significant correlation with age was seen for CSR chemical-shift ratio (r = 0.702, P < .001) but not SII signal intensity index (r = -0.196, P = .127). All subjects but one in group A and none in group B had signal intensity decrease at chemical-shift MR imaging. CONCLUSION: With dual-echo chemical-shift MR imaging, SII signal intensity index and CSR chemical-shift ratio have high accuracy to distinguish thymic hyperplasia from tumors, although overlapped CSR chemical-shift ratio values can occur in early adulthood.

Case 204: Nonketotic hyperglycemia-induced hemiballism-hemichorea.

HISTORY: An 87-year-old white woman presented to our emergency department with a 2-day history of involuntary movements of the right upper and lower extremities. The movements increased with action, decreased with relaxation, and disappeared during sleep. The patient's medical history included diabetes mellitus type 2, congestive heart failure, and hypertension. No history of parkinsonism or other neurologic disorders was reported. Furthermore, the patient had no prior history of dopamine antagonist or estrogen medication use. At admission, she was fully alert and oriented. A physical examination revealed her muscle tone and strength were normal on both sides; however, she reported transient weakness in the right limbs. There was no evidence of sensory impairment, and cranial nerves were normal. The deep tendon reflexes were symmetrically hypoactive. Her skin was pink, warm, and dry. Laboratory tests revealed poorly controlled diabetes mellitus, with a fasting blood glucose level of 410 mg/dL (22.8 mmol/L) and a hemoglobin A1C level of 18.0%. The urine examination was negative for ketones. Shortly after admission, the patient's blood sugar was controlled with insulin; this led to a steady correction of glycemia in the subsequent days. At admission, the patient underwent unenhanced brain computed tomography (CT) (Fig 1). Magnetic resonance (MR) imaging of the brain was performed 2 days later (Fig 2). After she was discharged from the hospital, the involuntary movements progressively decreased over the next few weeks until they disappeared. Two months later, follow-up unenhanced brain CT (not shown) showed the absence of abnormal findings.

A case of epigastric pain in the ED: late mechanical complication after vertical banded gastroplasty.

A 50-year-old woman presented to our emergency department complaining of recurrent epigastric stabbing pain on eating of 1 month duration. She had a history of morbid obesity treated 13 years before with laparoscopic vertical banded gastroplasty (VBG). Diagnosis was made by radiology, after upper gastrointestinal series and abdominal unenhanced computed tomography. These demonstrated intragastric band migration, with outlet stenosis of narrowed stomach. Vertical banded gastroplasty is a miniinvasive approach that gives the benefits of shorter hospital stay, less postoperative pain, and quicker functional recovery. However, many complications are known and require recognition to be appropriately treated. In our case, the history and clinical presentation led to a high suspicion of intraabdominal pathology due to postoperative complication. Radiologic upper gastrointestinal investigation and computed tomography findings were then decisive to detect the intragastric band migration.

Clinical implications and added costs of incidental findings in an early detection study of lung cancer by using low-dose spiral computed tomography.

INTRODUCTION: To prospectively evaluate the frequency and spectrum of incidental findings (IF) in a 5-year lung cancer screening program with low-dose spiral computed tomography (CT) and to estimate the additional costs of their imaging workup incurred from subsequent radiologic follow-up evaluation. MATERIALS AND METHODS: A total of 519 asymptomatic volunteers were enrolled. All IFs were reported and were considered clinically relevant if they required further evaluations or with clinical implications if they required more than one additional diagnostic test for characterization or medical and/or surgical intervention. RESULTS: IFs were commonly found (59.2%, 307/519 participants at baseline and 5.3% per year at 5-year follow-up [123 participants of 2341 LDsCT exams performed during follow-up], with an overall rate of 26.3%). IFs were categorized as previously unknown clinically relevant in 52 (10.0%) individuals at baseline. Of these, 36 (6.9%) individuals had IFs with clinical implications (10 clinically relevant, of which 6 had clinical implications, detected during the subsequent 5-year follow-up). The most common recommendations were for additional imaging of the thyroid and kidneys. Additional imaging was mainly performed by ultrasound (43/68 [63.2%]). Subsequent surgical intervention resulted from these findings in 7 (1.5%) subjects. Six malignancies were diagnosed (rate, 0.2% per year). Costs of subsequent radiologic follow-up studies were calculated as €4644.56 [U.S. $6575.04] at baseline and €1052.30 [U.S. $1489.69] at 5-year follow-up (average added costs per participant €8.95 [U.S. $12.67] and €2.25 [U.S. $3.19], respectively). CONCLUSIONS: Low-dose spiral CT commonly detects IFs. Some of these require further investigations to assess their clinical relevance. Although such IFs add little clinical benefit to the screening intervention, moderate incremental costs are incurred based on additional radiologic procedures generated during short-term follow-up, given the potential for positive effects on patient care.