Inflammatory pseudotumor in the mediastinum: imaging with (18)F-fluorodeoxyglucose PET/CT

An Interesting Case of Inflammatory Myofibroblastic Tumor Masquerading as Lymphoma Detected on 18F-FDG PET-CT

Inflammatory myofibroblastic tumors (IMT) are a rare set of tumors that have been reported in various areas of the body but not quite as often in systemic lymph nodes. Herein, we discuss the case of a 60-year-old woman who presented with bilateral cervical and axillary lymphadenopathy and a low-grade fever. She subsequently underwent a fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) as part of her evaluation. The scan revealed multiple hypermetabolic cervical, axillary, mediastinal, retroperitoneal, pelvic, and inguinal lymph nodes of various dimensions scattered throughout her body. Based on these findings, she was erroneously diagnosed to have lymphoma. It was only after histopathological correlation was the diagnosis revised to that of IMT, after which she was started on a course of oral corticosteroids. On follow-up imaging, she showed evidence of complete resolution of the involved lymph nodes. She has been disease-free for the past nine months after completing treatment. This case highlights the importance of including IMT as part of the differential diagnosis in suspected cases of lymphoma, giving credence to the phrase "all that glitters is not gold."

Inflammatory Myofibroblastic Tumor Mimicking a Cavitary Lesion in the Lung: A Case Report and a Comprehensive Literature Review

Inflammatory myofibroblastic tumors (IMTs) are a group of soft tissue neoplasms with a predilection for the lungs and abdominopelvic cavity, characterized by a mixture of fasciitis-like, compact spindle cells, hypocellular fibrous histologic patterns, and distinctive molecular features. Due to their unspecified symptoms and non-specific radiologic presentation, the histopathologic and immunohistochemical analysis of a biopsy specimen is crucial for the diagnosis. We present a case of a 30-year-old man with intermittent hemoptysis diagnosed with a pulmonary IMT. We aim to review the literature regarding its definition, clinical findings, diagnosis, treatment, and prognosis. The treatment for an IMT is based on its location and extent, including complete surgical resection, which has a good prognosis compared to corticosteroids, chemotherapy, radiotherapy, and non-steroidal immunomodulation in patients who are not good surgical candidates. Further investigative studies with larger sample sizes and longer meticulous follow-ups are needed to demonstrate this neoplastic disease's natural history and find appropriate management for it.

Rare presentation of inflammatory pseudotumour involving subcutaneous tissues with superficial fat sparing

We present a unique case of inflammatory pseudotumour involving gluteal subcutaneous tissue with the sparing of superficial fat and report its contrast-enhanced CT, F-18 fluorodeoxyglucose positron emission tomography/CT and pathological findings. Although rare, inflammatory pseudotumours have been reported with a diverse spectrum of locations; however, the involvement of the subcutaneous tissue overlying the gluteal muscles with sparing of the most superficial fat has not been reported.

Pitfalls of a Mixed Metabolic Response at PET/CT

Although the term mixed metabolic response is commonly used in PET/CT reports, it should be a red flag to reconsider the assumptions made by the PET scan reader. Fluorine 18 fluorodeoxyglucose (FDG) PET/CT is recognized as an accurate imaging method for detecting response to cancer therapies. Critical clinical decisions regarding therapy are dependent on accurate interpretation of findings. The use of standardized terminology for response assessment, such as that in the Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST), is highly recommended. With PERCIST, treatment response is categorized as complete metabolic response, partial metabolic response, stable metabolic disease, or progressive metabolic disease. Mixed metabolic response is not included in PERCIST. Rather, it is used colloquially to describe a scenario in which scanning performed after systemic cancer therapy reveals divergent findings, with some tumor foci responding and others not responding or even seen progressing. In PERCIST, mixed metabolic response should be described as stable metabolic disease or progressive metabolic disease. However, the PET/CT reader may also wish to suggest that individual tumors have heterogeneous genetic and/or other characteristics and consequently a mixed response to therapy. The concept of tumor heterogeneity is gaining momentum in cancer research and thus possibly leading to options for therapy targeted to oligometastases that are not responding. However, the authors suggest exercising extreme caution when PET/CT findings appear at first to reflect what some might call a mixed response. In addition, they have found that FDG PET/CT findings are often confounding owing to the simultaneous presence of two or more unrelated disease processes. Common examples include synchronous neoplasms, inflammatory processes, and treatment-related effects. Thus, an apparent mixed response is a red flag to reconsider whether all of the FDG-avid findings are actually metastases of the same cancer. Common mimics of a mixed metabolic response that do not represent true tumor heterogeneity are highlighted to improve the FDG PET/CT reader's recognition of these lesions.^©RSNA, 2019.

18F-Fluorocholine Uptake by a Head and Neck Meningeal Inflammatory Pseudotumor

F-Fluoro-ethyl-choline (F-FCH) PET/CT is widely used to study patients affected by prostate cancer. However, F-FCH may be taken-up by other neoplastic diseases, infections, and non-infective inflammatory processes. While this behavior may be an opportunity to study different diseases, on the other hand, this condition brings with it the source of error in the evaluation of the images. Here we present the case of a meningeal inflammatory pseudotumor evidenced by F-FCH.

Recurrent inflammatory myofibroblastic tumour of the lung: FDG PET/CT scan findings

Inflammatory myofibroblastic tumour (IMT) is a rare neoplasm, occurring most often in children and young adults. IMTs have intermediate biological behaviour with the chance of local invasion, recurrence and even distant metastasis. Wide range of clinical presentations makes the precise diagnosis of IMT more challenging. The best method for definitive diagnosis is tissue biopsy and newer imaging modalities including fleurodeoxyglucose (FDG) positron emission tomography (PET)/CT are useful tools in detection of disease recurrence or distant metastasis. Complete surgical resection is the best-known treatment for this tumour. Here we are presenting an IMT case in a 12-year-old girl in which her recurrent pulmonary IMT was diagnosed based on FDG PET/CT findings and referred for further salvage treatment. Overall imaging modalities are not specific, but PET/CT scan can be useful tool for evaluation of IMT regarding initial staging and restaging to assess treatment response and recurrence.

Rare Endobronchial Inflammatory Myofibroblastic Tumor in Pediatric Patient Detected on PET/CT Imaging

Inflammatory myofibroblastic tumor (IMT) can be seen in all age groups, although it is more common in children and adolescents. We report the FDG PET/CT findings in an 8-year-old boy with endobronchial IMT. Endobronchial IMT is more commonly seen in young adults.

IMAGING DIAGNOSIS - MAGNETIC RESONANCE IMAGING OF INTRACRANIAL INFLAMMATORY FIBROSARCOMA IN A MIXED BREED DOG

An 8-year-old mixed-breed dog presented with progressive behavioral changes and altered mentation. Magnetic resonance imaging (MRI) of the brain revealed an olfactory and frontal lobe extra-axial mass. The mass exhibited the following MRI signal intensity characteristics: T2W mixed, T1W iso- to hypointense, FLAIR hyperintense, and strong contrast enhancement. The mass was removed with cavitronic ultrasonic surgical aspirator (CUSA) assisted neurosurgery. Based on histopathological appearance and immunohistochemistry, the diagnosis of inflammatory fibrosarcoma was made. To our knowledge, this is the first report describing MRI characteristics of intracranial inflammatory fibrosarcoma in the veterinary literature.