Usefulness of F-18 FDG PET/CT in a Case of Kaposi Sarcoma With an Unexpected Bone Lesion

Yield of FDG PET/CT for Defining the Extent of Disease in Patients with Kaposi Sarcoma

Simple Summary

The potential role of positron emission tomography/computed tomography with fluorodeoxyglucose (FDG PET/CT) for assessing the extent of Kaposi sarcoma is not well studied. We analyzed FDG PET/CTs performed on 75 patients referred to our department for Kaposi sarcoma staging or restaging. FDG PET/CTs detected most lymph nodes, bone, and muscle lesions, whereas digestive and mucous lesions could be missed. Most cutaneous lesions can be identified when whole-body FDG PET/CT (including lower limbs) is performed. Thus, a true whole-body FDG PET/CT can be recommended for staging purposes in patients with active Kaposi sarcoma and, if positive, be useful for therapeutic evaluation and follow-up.

Abstract

Background: Positron emission tomography/computed tomography with fluorodeoxyglucose (F-18) (FDG PET/CT) is increasingly used in Kaposi sarcoma (KS), but its value has not been assessed. Objectives: In this study, we aimed to evaluate the diagnostic accuracy of FDG PET/CT to define the extent of disease in KS. Methods: Consecutive patients with KS referred to our department for FDG PET/CT were included. The diagnostic accuracy of FDG PET/CT for cutaneous and extra-cutaneous KS staging was assessed on a per lesion basis compared to staging obtained from clinical examination, standard imaging, endoscopy, histological analyses, and follow-up. Results: From 2007 to 2017, 75 patients with FDG PET/CT were analyzed. The sensitivity and specificity of FDG PET/CT for the overall detection of KS lesions were 71 and 98%, respectively. Sensitivity and specificity were 100 and 85% for lymph nodes, 87 and 98% for bone, 87 and 100% for lungs, and 100 and 100% for muscle involvement, whereas sensitivity was only 17% to detect KS digestive involvement. The sensitivity of the diagnostic for KS cutaneous involvement increased from 73 to 88% when using a whole-body examination. Conclusion: FDG PET/CT showed good sensitivity and specificity for KS staging (digestive involvement excepted) and could be used for staging patients with active KS.

Current and Future Tools for Diagnosis of Kaposi's Sarcoma

Simple Summary

Kaposi’s sarcoma, a rare opportunistic tumor, is observed in four epidemiological conditions (AIDS-related, iatrogenic, endemic or classic KS). Although in most cases KS is an indolent disease, it can be locally aggressive and/or it can invade other organs than the skin, resulting in more severe presentations, especially in patients with severe immunosuppression. There is no consensus on the imaging workup that is necessary for either the initial staging of the disease or the follow-up. Future perspectives include the use of certain non-invasive imaging tools that may help to evaluate the clinical response to treatment, as well as certain new histological markers that may help in guiding the treatment planning for this atypical neoplasm.

Abstract

Kaposi’s sarcoma (KS) is a rare, atypical malignancy associated with immunosuppression and can be qualified as an opportunistic tumor, which responds to immune modulation or restoration. Four different epidemiological forms have been individualized (AIDS-related, iatrogenic, endemic or classic KS). Although clinical examination is sufficient to diagnose cutaneous lesions of KS, additional explorations are necessary in order to detect lesions involving other organs. New histological markers have been developed in recent years concerning the detection of HHV-8 latent or lytic proteins in the lesions, helping to confirm the diagnosis when it is clinically doubtful. More recently, the evaluation of the local immune response has also been shown to provide some guidance in choosing the appropriate therapeutic option when necessary. We also review the indication and the results of conventional radiological imaging and of non-invasive imaging tools such as ¹⁸F-fluoro-deoxy-glucose positron emission tomography, thermography and laser Doppler imaging for the diagnosis of KS and for the follow-up of therapeutic response in patients requiring systemic treatment.

Vascular tumors in infants and adolescents

Malignant vascular tumors as part of the vascular anomalies spectrum are extremely rare in children and young adults. Instead, benign vascular neoplasias are frequently encountered in the pediatric patient population. While vascular malformations are congenital vascular lesions, originating from a mesenchymal stem cell defect, vascular tumors are neoplastic transformations of endothelial and other vascular cells. The appropriate differential diagnosis and nomenclature according to the classification of the International Society for the Study of Vascular Anomalies (ISSVA) is decisive to initiate correct therapy. While infantile hemangioma can be routinely diagnosed by clinical means and rarely require therapy, more rare vascular tumors are frequently difficult to diagnose, require dedicated cross-sectional imaging, and benefit from an interdisciplinary treatment approach. The focus of this review is to provide an overview over the spectrum of vascular tumors, typical imaging characteristics, and summarize treatment options including interventional radiology approaches.

Multiple Intravascular Papillary Endothelial Hyperplasia of Bone Mimicking Malignancy on 99mTc-MDP Bone Scan and 18F-FDG PET/CT

Multiple intravascular papillary endothelial hyperplasia involved with bone is rare. In this study, we present the case of a 53-year-old woman having occasional chest pains located in the middle of the sternum and the left chest wall. Multiple intravascular papillary endothelial hyperplasia lesions with high metabolism distributed in the sternum, left ribs, 12th thoracic vertebra, and left ilium on bone scintigraphy as well as PET/CT, which were easily misdiagnosed as bone malignant tumors. Increased awareness of this benign lesion and its high metabolic findings will improve preoperative diagnosis and avoid misinterpretation that may lead to an unnecessary invasive treatment.

Kaposi sarcoma can also involve the heart

Kaposi sarcoma (KS) is a low-grade angioproliferative tumor associated with infection with human herpes virus 8 (HHV-8). The disease was named after Moritz Kaposi, a Hungarian dermatologist who first described it in 1872 as 'idiopathic multiple pigmented sarcoma of the skin.' HHV-8 infection is required for the development of KS, but not all infected persons develop the disease. KS is also considered an acquired immune deficiency syndrome (AIDS)-defining illness by the Centers for Disease Control and Prevention guidelines. According to data from the United States AIDS and cancer registries, both KS and non-Hodgkin lymphoma are the most common malignancies associated with human immunodeficiency virus (HIV) infection. However, the incidence of both malignancies has decreased dramatically since 1996 following the widespread utilization of highly active antiretroviral therapies. HIV-associated KS can involve virtually any site in the body including lymph nodes, gastrointestinal tract, respiratory system, heart, pericardium, bone marrow, and other visceral organs. However, cutaneous disease is the most common and is the usual initial presentation for KS. KS-related pericardial effusion can be a life-threatening emergency and should be considered in HIV/AIDS patients who present with signs and symptoms of pericardial effusion. The importance of diagnosing and differentiating KS-related pericardial effusion from other causes of pericardial effusion lies in the differences in the treatment and management in comparison to other etiologies of pericardial effusion. We report a case of a 54-year old man who presented to our hospital with a large pericardial effusion and was subsequently diagnosed to have HIV-related KS pericardial effusion. A brief review of the literature on the diagnosis and management is also presented.

Flip-flop phenomenon in systemic sclerosis on fluorodeoxyglucose positron emission tomography/computed tomography

Systemic sclerosis (SSc) is a rare autoimmune disease, which may affect multiple organ systems. Fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) can demonstrate the degree and anatomical extent of involvement in the entire body and coexisting malignancies in connective tissue diseases. We present a case of SSc with an increased 18F-FDG uptake in the cutaneous and subcutaneous tissues even higher than the neighboring skeletal muscles (“flip-flop phenomenon,” that is, an increased 18F-FDG uptake in the skin but a decreased 18F-FDG uptake in the skeletal muscles).

18F-FDG PET detection of unknown primary malignancy in dermatomyositis

Dermatomyositis is an inflammatory myopathy that has an association with malignancy in adults. We present a patient who initially presented with adenopathy and progressive muscular weakness and was diagnosed with dermatomyositis and lung carcinoma on further investigation. Whole-body PET/CT scan revealed diffuse proximal muscle hypermetabolism representing the inflammatory nature of dermatomyositis, and an intensely FDG-avid primary right lower lung small cell lung carcinoma and metastatic thoracic lymphadenopathy. PET/CT imaging may offer an "all-in-one" procedure as an alternative to other diagnostic procedures, reducing the number of unnecessary investigations in patients presenting with paraneoplastic syndromes searching for underlying malignancy.

Plasmablastic lymphoma of the oral cavity in an HIV-positive patient: staging with 18F-FDG PET/CT

Plasmablastic lymphoma of the oral cavity is a very rare and only recently recognized entity that has been identified almost exclusively in HIV-infected individuals. It has a predilection for the oral cavity, often exhibits very aggressive behavior and has a poor prognosis. The use of 18F-FDG PET/CT in the evaluation of HIV-associated lymphomas is a recent development, and its use in the staging of plasmablastic lymphoma of the oral cavity has not been previously reported. This rare report highlights the usefulness of 18F-FDG PET/CT in the staging of plasmablastic lymphoma of the oral cavity.