Rare Presentation of Inflammatory Lung Disease and Subcutaneous Nodules on FDG PET/CT Scan: Brief Discussion of Differential Diagnoses.

ABSTRACT: We present a 37-year-old man with cough and progressive dyspnea for the past 3 years. According to inconclusive chest CT scan and lung biopsy histopathology findings, the patient referred for 18F-FDG PET/CT scan for further evaluation. Classic pulmonary manifestations of Langerhans cell histiocytosis were seen on CT images with intense FDG uptake on PET scan. Moreover, PET/CT revealed multiple hypermetabolic subcutaneous foci throughout his body. Finally, the patient was treated with corticosteroids. Follow-up chest CT images demonstrated improvement of lung lesions in accordance with improvement in the patient's symptoms. We are briefly discussing differential diagnoses in this patient.

Steatotic Hepatitis Presenting as a Huge Hypermetabolic Liver Mass.

ABSTRACT: FDG PET/CT scan is a diagnostic imaging modality for oncologic patients, but with false-positive findings in inflammatory diseases. In this interesting case, we present a 24-year-old woman with history of giant cell tumor of the bone (lumbar vertebrae) who underwent whole-body FDG PET/CT scan for treatment response evaluation. FDG PET/CT scan demonstrated a large hypermetabolic tumoral mass lesion in segment VI/VII of the right hepatic lobe. A range of malignant versus benign lesions should be considered as differential diagnoses, including metastasis, primary cholangiocarcinoma, hepatocellular carcinoma, focal nodular hyperplasia, and infection. Final diagnosis of "steatotic hepatitis" after CT-guided biopsy was established.

Interesting Manifestation of Autoimmune Encephalitis on FDG PET Scan.

ABSTRACT: We are presenting a 22-year-old man with intractable seizures. Autoimmune epilepsy, vasculitis, and paraneoplastic disorder were among initial differential diagnoses. His initial laboratory tests and toxicology screen were unremarkable. His initial brain MRI demonstrated generalized cortical atrophy. Features such as progressive encephalopathy, neuropsychiatric symptoms, personality change, and autonomic dysfunction were in favor of autoimmune encephalitis. Autoantibody evaluations including anti-NMDA receptor (NR1) IgG were negative in both serum and CSF samples. FDG PET scan demonstrated intense FDG uptake in the basal ganglia, more prominent in the caudate nuclei and putamina, which is one of the known autoimmune encephalitis imaging features.

Diagnostic value of non-contrast brain computed tomography in the evaluation of acute cerebral venous thrombosis.

Acute cerebral vein thrombosis is usually seen as increased attenuation in brain non-contrast computed tomography. It is so helpful to define measurable parameters for subjective evaluation of sinus thrombosis in non-enhanced brain computed tomography, especially where advanced neuroimaging techniques are not available. The purpose of this study is to evaluate the diagnostic value of venobasilar attenuation ratio and venobasilar attenuation difference in the evaluation of acute cerebral venous sinuous thrombosis in non-enhanced brain CT scan. Fifty confirmed cases of acute cerebral vein thrombosis were sex- and age-matched with 73 subjects who did not have the condition. Average venous sinus attenuation, Hounsfield to hematocrit ratio, basilar artery density, venobasilar attenuation ratio and venobasilar attenuation difference were measured. Mean attenuation was 65.8 in thrombosed and 44.9 in non-thrombosed sinuses (P < 0.0001). A cutoff absolute sinus attentuaion of 61 HU led to a sensitivity of 82%, specificity of 100% and accuracy of 92%. A cutoff ratio of 1.4 for venobasilar ratio led to a sensitivity of 100%, specificity of 78% and accuracy of 87%. A cut-off value of 24 for venobasilar difference resulted in the sensitivity of 80%, specificity of 100% and accuracy of 92%. The additional measurement of venous sinus and basilar artery attenuations and calculation of venobasilar ratio and difference can increase the sensitivity and specificity of NCCT in the diagnosis of acute CVST.

Galactocele in the Axillary Accessory Breast Mimicking Suspicious Solid Mass on Ultrasound.

Galactoceles are the most common benign breast lesions during breastfeeding period that can mimic carcinomas. We report a galactocele with malignant appearance on ultrasound in the accessory breast. The patient was a 32-year-old lactating woman presented to our hospital for considerable swelling in the left axilla. Ultrasound examination revealed a hypoechoic mass with heterogeneous echogenicity and irregular shape and margins. Sonography-guided aspiration was performed. Aspiration of milky fluid and resolution of the axillary lump after aspiration confirmed the diagnosis of galactocele. Galactocele can present as a suspicious tumoral lesion in the axillary accessory breast and diagnostic aspiration can help in correct diagnosis of this rare lesion in the accessory breast.