AIMS: With ongoing intensive vaccination programme against COVID-19, numerous cases of adverse reactions occur, some of which represent rare events. Enlargement of the injection site's draining lymph nodes is increasingly reported, but is not yet widely recognised as being possibly associated with recent vaccination. As patients at risk of a severe course of COVID-19, indicated by their medical history such as a previous diagnosis of malignancy, receive priority vaccination, newly palpable lymph nodes raise concerns of disease progression. In this case series, we report on five patients who presented with enlarged lymph nodes after COVID-19 vaccination.METHODS: Sonography guided fine needle aspiration (FNA) was performed in five patients presenting with PETpositive and/or enlarged lymph nodes after COVID-19 vaccination with either the Pfizer-BioNTech or Moderna vaccine.RESULTS: COVID-19 vaccination had been carried out in all cases, with an interval of between 3 and 33 days prior to FNA. Three of five patients had a history of neoplasms. The vaccine was administered into the deltoid muscle, with subsequent enlargement of either the cervical, supra-, infra-or retroclavicular, or axillary lymph nodes, in four out of five cases ipsilaterally. In all cases, cytology and additional analyses showed a reactive lymphadenopathy without any sign of malignancy.CONCLUSIONS: Evidence of newly enlarged lymph nodes after recent COVID-19 vaccination should be considered reactive in the first instance, occurring owing to stimulation of the immune system. A clinical follow-up according to the patient's risk profile without further diagnostic measures is justified. In the case of preexisting unilateral cancer, vaccination should be given contralaterally whenever possible. Persistently enlarged lymph nodes should be re-evaluated (2 to) 6 weeks after the second dose, with additional diagnostic tests tailored to the clinical context. Fine needle aspiration is a well established, safe, rapid and cost-effective method to investigate an underlying malignancy, especially metastasis. Recording vaccination history, including date of injection, site and vaccine type, as well as communicating this information to treating physicians of different specialties is paramount for properly handling COVID-19 vaccine-associated lymphadenopathy.

Computed tomographic evaluation of the distal aspect of the deep digital flexor tendon (DDFT) in horsesThe objective of this study was to image the deep digital flexor tendon (DDFT) in its normal position by means of computed tomography from distal aspect of the proximal phalanx (P1) down to the flexor surface of the distal phalanx (P3) in 10 predefined cutting planes. A total of 30 front extremities of randomly selected Warmblood horses were used. Criteria for evaluation were differntiation of the DDFT from surrounding structures, definition of its shape, contour and structure as well as determination of its density and measurements. The density of DDFT was determined at three sites in all transversal planes, the depth was determined at three locations in palmar to dorsal and the width in medial to lateral direction. The mean values for density amounted to 106.8 HU (s 12.7 HU), for depth 5.04 mm (s 0.66 mm) and for width to 35.05 mm (s 2.99 mm). Significant differences were demonstrated in between planes as well as within planes comparing measurements by statistical analysis, thus demonstrating that the data predominantly follow distinct rules. Within the transversal plane (distal navicular to proximal) lowest values for density were found in the axial region of interest with significantly lower values for depth axially. Also a distal to proximal increase in values for depth and a decrease for width were noted. Apart from determining standard values, CT-images of pathological DDFT were shown based on four samples. This was done in comparison to sonographic images and to specific postmortem findings. Measured values found in regions with pathological lesions were evaluated by referring to the mean of standard values plus/minus two standard deviations. The importance and high value of computed tomography in imaging the distal aspect of the DDFT was not only confirmed by comparing different images by means of subjective criteria but also by objectively collected data for density and distance.

Calculation of iodine-131 activities for radioiodine treatment (RIT) in patients with disseminated thyroid autonomy may be difficult because of uncertainties in the determination of the autonomous volume (vol(aut)). The algorithm established by Emrich is used for calculation of the vol(aut) based on the TcTUs (technetium thyroid uptake under TSH suppression) (vol(aut)= 5xTcTUs+0.6). Clinical experience using this approach has shown that there is a negative correlation between increasing TcTUs and the results of RIT. Our aim was to identify the reasons for this observation as well as to assess the relation between TcTUs and sonographic vol(aut). Furthermore, we intended to find an alternative algorithm for the TcTUs-based calculation of the vol(aut). Data from 100 patients with unifocal autonomy who met strict inclusion criteria were used to evaluate the correlation between TcTUs and sonographic vol(aut). Using Marinelli's algorithm, we calculated the therapeutic activities for a standardised patient at a target dose of 300 Gy. The vol(aut) was determined based on the TcTUs using the four published algorithms [Emrich 1993 (vol(aut)= 5xTcTUs+0.6), Kreisig 1992 (vol(aut)=10xTcTUs-9.3), Joseph 1977 (vol(aut)=8.33xTcTUs-6.67) and 1994 (vol(aut)=2.88xTcTUs+0.09)]. We then compared the results of the calculation of therapeutic activities obtained using Emrich's algorithm (with known success rates) with those obtained by the other algorithms in order to determine which algorithm would lead to better results in RIT. Only a weak correlation was found between the TcTUs and the sonographic vol(aut) ( r(2)=0.39). The calculated therapeutic activities of (131)I were similar for all algorithms at a TcTUs of around 2% but Joseph's (1977) and Kreisig's (1992) algorithms resulted in clearly higher activities than Emrich's algorithm at a TcTUs above 2%. The need for target doses to increase with TcTUs in RIT may be overcome by the use of adequate algorithms for determination of the vol(aut). The algorithm published by Joseph and co-workers in 1977 probably offers the most reliable approach to the TcTUs-based calculation of vol(aut) in RIT. In contrast to the other algorithms, it is based on autoradiographic planimetric data. Thus, it takes into account the polyclonal origin of thyroid nodules as well as the presence of regressive or cystic changes. The well-established algorithm of Emrich underestimates the true vol(aut), which explains the decreasing success of RIT with increasing TcTUs.

Calcifying fibrous tumor (CFT) is a benign tumor entity which can present in a variety of different sites. Till date, eight cases with a mediastinal manifestation have been published in literature. Surgical removal is the treatment of choice for this often incidentally detected tumor. Surgery of thoracic CFT may be challenging due to its localization within the mediastinum. A 10-year old boy with a right-sided thoracic pectus carinatum-like deformity was referred for further evaluation, incidentally, revealing a mediastinal mass in computed tomography (CT). Laboratory results were all within normal range. Magnetic resonance imaging (MRI) showed a large tumor in the upper anterior mediastinum suggesting expansive but not infiltrative character. The tumor was displacing surrounding structures like the heart and the diaphragm. Lower venous stasis with dilation of the inferior cava vein could be demonstrated. The tumor was considered to be of benign dignity and surgical removal was indicated. Complete tumor resection could be achieved through a sternotomy approach, along with thymectomy. A partial resection of both the pericardium and diaphragm was required due to adhesion with soft tissue at those sites. The specimen's size was 320 mm × 145 mm × 100 mm, histologically confirmed as CFT. The patient showed no residual tumor at 3- and 9-month follow-up. This case is a report on a large mediastinal CFT which underwent successful complete surgical removal. Following tumor resection, prognosis is considered to be good; however, key issue is complete resection to avoid local tumor recurrence.