F-18 FDG Uptake Associated With Elastofibroma Dorsi

Musculoskeletal Pitfalls on Fluorodeoxyglucose F 18 PET-Computed Tomography: Pictorial Review

A wide range of musculoskeletal processes can demonstrate increased uptake on PET-computed tomography (CT) with fluorodeoxyglucose (FDG) F 18, including reactive, benign neoplastic, inflammatory, traumatic, posttreatment, and arthritic conditions that may mimic malignancy. In addition, physiologic causes of increased FDG uptake such as asymmetric muscle use and presence of brown fat can lead to increased FDG uptake and potential false-positive results. This article presents various case examples of non-malignant musculoskeletal hypermetabolism on 18F-FDG PET-CT and describes useful tools to avoid the potential pitfall of misinterpreting these as malignancy.

How We Read Oncologic FDG PET/CT

¹⁸F-fluorodeoxyglucose (FDG) PET/CT is a pivotal imaging modality for cancer imaging, assisting diagnosis, staging of patients with newly diagnosed malignancy, restaging following therapy and surveillance. Interpretation requires integration of the metabolic and anatomic findings provided by the PET and CT components which transcend the knowledge base isolated in the worlds of nuclear medicine and radiology, respectively. In the manuscript we detail our approach to reviewing and reporting a PET/CT study using the most commonly used radiotracer, FDG. This encompasses how we display, threshold intensity of images and sequence our review, which are essential for accurate interpretation. For interpretation, it is important to be aware of benign variants that demonstrate high glycolytic activity, and pathologic lesions which may not be FDG-avid, and understand the physiologic and biochemical basis of these findings. Whilst FDG PET/CT performs well in the conventional imaging paradigm of identifying, counting and measuring tumour extent, a key paradigm change is its ability to non-invasively measure glycolytic metabolism. Integrating this "metabolic signature" into interpretation enables improved accuracy and characterisation of disease providing important prognostic information that may confer a high management impact and enable better personalised patient care.

Incidental detection of elastofibroma dorsi on PET-CT: initial findings and changes in tumor size and standardized uptake value on serial scans

OBJECTIVE

We describe changes in elastofibroma dorsi (EFD) as observed in serial fluorine-18 fluorodeoxyglucose (F-FDG) PET-computed tomography (CT) imaging studies.

MATERIALS AND METHODS

F-FDG PET-CT studies carried out between January 2006 and January 2015 at a single institution were reviewed by an experienced radiologist and nuclear medicine specialist. When available, previous or subsequent imaging studies were reviewed to evaluate changes in EFD.

RESULTS

Of 28 500 PET-CT studies carried out, EFD was identified in 68 from 20 patients (mean age 67.1±10.2 years; 14 women). Five patients had unilateral lesions and 15 patients had bilateral lesions. Eighteen patients had oncologic diseases. The mean size of EFD at first presentation was 13.95±5.90 mm and the mean homogeneous low-grade F-FDG uptake was maximum standardized uptake value (SUVmax) 2.24±0.95. One or more additional CT scans were performed in 17 patients; the mean interval between the first and last scans was 57.4±39.2 months. EFD was unchanged in size in 7/17 (41%) and showed slow growth in 10/17, reaching a mean size of 19 mm. The mean monthly growth rate was 0.1±0.10 mm. PET imaging in 11 patients showed a mean first SUVmax of 2.08±1.17 and a mean last SUVmax of 2.74±1.05 after a mean of 47.5±31.5 months (P=0.63).

CONCLUSION

Serial PET-CT studies may show a stable or slowly enlarging mass on a CT scan without changes in F-FDG uptake on PET imaging. Familiarity with CT appearances and F-FDG uptake of EFD are important for correct interpretation of F-FDG PET-CT studies.

[Elastofibroma of dual anterior and thoracic dorsal localization in children]

L’élastofibrome est une pseudotumeur des tissus mous typiquement localisée sous la pointe de l'omoplate. Il est caractérisé par la prolifération de tissus fibreux et adipeux et affecte plus fréquemment les femmes âgées. Nous présentons un cas d’élastofibrome chez une fille de 9 ans.

[Bilateral elastofibroma dorsi]

BACKGROUND

Elastofibroma dorsi (EFD) is a rare form of benign soft-tissue tumour that is almost always located at the lower pole of the scapula, deep to the serratus anterior muscle. There are few reports in the dermatological literature since it rarely develops in skin or subcutaneous tissue.

CASE REPORT

We present the case of a 59-year-old man with bilateral elastofibroma dorsi. Physical examination showed two bilateral scapular masses, better visualized in abduction or antepulsion. They were firm, painless, mobile, covered by normal skin, and measured 40/35 mm on the right and 50/55 mm on the left. Ultrasound of soft tissue and a chest CT scan showed two heterogeneous masses (tissue and fat) within the serratus anterior muscle measuring 30/15 mm on the right and 60/19 mm on the left. Histopathological study of a deep biopsy done on the right helped to confirm the diagnosis of EFD. Tumour resection was done on the right.

DISCUSSION

Elastofibroma dorsi is an uncommon, benign, non-encapsulated pseudo-tumour occurring in connective tissue of the infrascapular region of elderly patients. Another mass must be sought in all cases in the corresponding contralateral site since this form of tumour is often bilateral.

CONCLUSION

EFD must be considered in the differential diagnosis of shoulder masses in elderly patients.

FDG-PET/CT imaging of elastofibroma dorsi

OBJECTIVE

The purpose of this study was to assess retrospectively the characteristics of FDG uptake in elastofibroma dorsi using integrated PET/CT.

METHODS

From 10,261 oncology FDG-PET/CT scans performed over a 2-year period, findings suggestive of elastofiboma dorsi were observed in 46 FDG-PET/CT scans of 34 patients. As 20 patients had bilateral lesions and 14 had unilateral lesions, a total of 75 elastofibroma dorsi lesions on images were identified in this study. For visual analysis of intensity of FDG uptake , a four-point grading system was used: grade 0 for no uptake, grade 1 for less uptake than the liver, grade 2 for uptake comparable to the liver, and grade 3 for intense uptake greater than the liver. For quantitative analysis, the standardized uptake value (SUV) was calculated. The relationships between SUV and age, blood glucose level, lesion size, and related symptoms were also assessed.

RESULTS

Among the 75 lesions, 4 had an uptake grade of 0, 41 had grade 1, 25 had grade 2, and 5 had grade 3. The mean SUV (±SD) of the 75 lesions was 2.0 ± 0.63 (range 0-5.1). The Pearson correlation coefficient test indicated a weak positive correlation between SUV and lesion size and no correlation between SUV and either age or blood glucose level. The SUVs of patients with symptoms due to the disease and patients without symptoms were almost the same.

CONCLUSION

Mild and moderate uptake of FDG is frequently observed in elastofibroma dorsi, which should not be misinterpreted as abnormal accumulation observed in malignant lesions.

Characterization of Elastofibroma Dorsi with (18)FDG PET/CT: a retrospective study

Elastofibroma dorsi has been described in the literature as an unusual tumor or pseudotumor. However, autopsies and imaging studies have revealed that it is a non-negligible finding.

PURPOSE

The aim of this study has been to illustrate and become familiar with this type of lesion in order to prevent misdiagnosis.

MATERIALS AND METHODS

From 3 December 2008 to 5 January 2010, 1,751 patients were evaluated with (18)FDG-PET/CT. Of these, 29 cases of elastofibroma dorsi were recorded as an incidental finding. A retrospective and descriptive analysis was performed on this study series.

RESULTS

The study showed a prevalence of 1.66%. Out of the 29 findings, 22 (75.86%) were females and 7 (24.14%) males. Seventeen (58.62%) cases were bilateral, 12 (41.38%) unilateral and the SUVmax ranged from 1.4 to 3.2. These lesions were reported as soft tissue density images with mild or moderate diffuse metabolic activity.

CONCLUSION

The elastofibroma dorsi is a relatively common finding in PET/CT that should be known in order to avoid making wrong diagnoses.

Assessment of liver metastases from colorectal adenocarcinoma following chemotherapy: SPIO-MRI versus FDG-PET/CT

PURPOSE

This study compared superparamagnetic iron-oxide-enhanced magnetic resonance imaging (SPIO-MRI) and combined fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET/CT) in evaluating liver metastases from colorectal adenocarcinoma following chemotherapy.

MATERIALS AND METHODS

Nineteen patients were included in this retrospective study. SPIO-MRI and PET/CT results were compared with surgery, intraoperative ultrasound and pathology results in 11 patients and with the follow-up in eight patients.

RESULTS

SPIO-MRI and PET/CT identified 125 and 71 metastases, respectively. False negative lesions were 11 for SPIO-MRI and 65 for PET/CT. In the whole study population, the per-lesion analysis of SPIO-MRI and PET/CT showed a sensitivity of 92% and 52% (p<0.001) and the per-segment analysis a sensitivity of 99% and 79% (p<0.001), respectively. In patients who underwent surgery, the per-lesion analysis of SPIO-MRI and PET/CT showed a sensitivity of 85% and 58% (p<0.05) and the per-segment analysis a sensitivity of 97% and 63% (p<0.05), respectively. In patients who underwent follow-up, the per-lesion analysis of SPIO-MRI and PET/CT showed a sensitivity of 97% and 47% (p<0.001) and the per-segment analysis a sensitivity of 100% and 63% (p<0.007), respectively. For lesions ≥15 and <30 mm and for lesions <15 mm, SPIO-MRI demonstrated a higher sensitivity than PET/CT (p<0.001).

CONCLUSIONS

SPIO-MRI appears superior to PET/CT in evaluating liver metastases from colorectal adenocarcinoma following chemotherapy.

Diagnosis of elastofibroma

Elastofibroma is a relatively rare soft tissue mass. The lesion is probably reactive and occurs most commonly in the periscapular region. It is a degenerative benign neoplasm with the clinical appearence of a malignant tumour. The present report describes the case of a 70-year-old man with bilateral elastofibroma. The diagnosis was established with needle aspiration biopsy and positron emission tomography/computed tomography. The present case suggests that needle aspiration biopsy and positron emission tomography/computed tomography are highly useful in the diagnosis of this rare, benign tumour.

Role of modern imaging techniques for diagnosis of infection in the era of 18F-fluorodeoxyglucose positron emission tomography

During the past several years, it has become quite evident that positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) imaging can play a major role in the management of patients with suspected infection. Particularly, several groups have demonstrated that this powerful imaging methodology is very effective in the evaluation of osteomyelitis, infected prostheses, fever of unknown origin, and AIDS. In view of its extraordinary sensitivity in detecting disease activity and the ability to quantitate the degree of FDG uptake, PET might prove to be an appropriate modality for monitoring disease activity and evaluating response to therapy. FDG-PET has many advantages over existing imaging techniques for the diagnosis of infectious diseases. These include feasibility of securing diagnostic results within 1.5 to 2 h, excellent spatial resolution, and accurate anatomical localization of sites of abnormality. The availability of PET/computed tomography as a practical tool has further enhanced the role of metabolic imaging in many settings. In the future, this modality is very likely to be employed on a routine basis for detecting, characterizing, and monitoring patients with suspected and proven infection.

Elastofibroma Dorsi: Clinicopathologic Review of 6 Cases

Elastofibroma dorsi is a rare, benign lesion arising from connective tissue and usually found at the angle of the scapula. Surgical resection is often indicated in the presence of an enlarging mass or when malignancy can not be excluded. Herein we report our most recent case of elastofibroma dorsi and our review of 6 cases from the past 16 years.

Bilateral elastofibroma dorsi

Elastofibromas (EFD) are rare benign soft tissue tumors that are almost always located at the inferior pole of the scapula, deep to the serratus anterior muscle. They are more frequent in elderly women. Their anatomical location and a distinctive clinical symptom distinguish them from malignant soft tissue tumours. They can usually be diagnosed on the basis of their imaging characteristics. Despite their low incidence, these lesions should be kept in mind to differentiate them from malignant tumours and to avoid unnecessary biopsies and wide or radical surgery. We present the case of a 55-year-old woman who complained of chronic pain related to a right infrascapular mass. She was diagnosed by magnetic resonance imaging (MRI) of bilateral subescapular tumor masses both compatible with elastofibroma. She underwent resection of the symptomatic right lesion through an amyotomical approach.