[18F]fluorodeoxyglucose positron emission tomography is a useful tool to diagnose the early stage of Takayasu's arteritis and to evaluate the activity of the disease

Takayasu's arteritis (TA) is a rare disease that can be difficult to diagnose in its early stage. A young woman with a fever and neck pain was thought to have TA, although computed tomographic angiography did not show any specific changes of the arteries. [¹⁸F]fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG-PET) was performed to detect the source of the inflammation. Specific accumulation of [¹⁸F]FDG-6-phosphate in the thoracic aorta and its direct branches was observed, leading to a diagnosis of TA. [¹⁸F]FDG-PET is therefore considered to be useful for the diagnosis of early-stage TA.     

[18F]fluorodeoxyglucose positron emission tomography is a useful tool to diagnose the early stage of Takayasu's arteritis and to evaluate the activity of the disease

Abstract

Takayasu's arteritis (TA) is a rare disease that can be difficult to diagnose in its early stage. A young woman with a fever and neck pain was thought to have TA, although computed tomographic angiography did not show any specific changes of the arteries. [¹⁸F]fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG-PET) was performed to detect the source of the inflammation. Specific accumulation of [¹⁸F]FDG-6-phosphate in the thoracic aorta and its direct branches was observed, leading to a diagnosis of TA. [¹⁸F]FDG-PET is therefore considered to be useful for the diagnosis of early-stage TA.     

Recurrent pericarditis revealing a systemic sarcoidosis

Introduction

Sarcoidosis is a systemic granulomatous disorder of unknown cause, mainly involving the lung and the mediastinum. Involvement of the pericardium and peritoneum is rare, but can be the first manifestation of the disease.

Case report

A 55-year-old female patient was followed-up for a recurrent “idiopathic” pericarditis. Diagnostis was challenged when she secondarily presented with enlarged hilar and mediastinal lymph nodes associated with pulmonary “nodules”. Imaging with ¹⁸F-FDG positron emission tomography with computed tomography showed multiple hypermetabolic foci in the mediastinum and peritoneum, which suggested a malignant disorder. Finally, histopathological evaluation of the peritoneal nodules revealed a sarcoidosis. A corticosteroid therapy was initiated and disease course was favourable.

Conclusion

This case report highlights the importance of a unique explanation for a patient presenting with recurrent pericarditis associated with a systemic disease. Although rare, sarcoidosis should be discussed and diagnostic procedures should be performed to obtain histological confirmation.     

Impact of positron emission tomography on strategy in liver resection for primary and secondary liver tumors

Purpose Outcome of patients with metastatic disease mainly depends on accurate preoperative tumor staging. ¹⁸[F]fluorodeoxyglucose positron emission tomography (18F-PET) has been proven to be a valuable diagnostic tool in a number of different tumors but its direct influence on liver surgery has not been thoroughly investigated.Materials and methods Between July 1999 and March 2000, 50 consecutive patients with 174 suspected liver lesions were admitted to the University Hospital Jena. All 50 patients underwent abdominal ultrasound, CT-scan, and 18-FDG positron emission tomography scanning. In 23 patients the diagnostic work-up was completed by MRI scan.Results Altogether there were a total of 174 histologically proven intrahepatic lesions, nine of which were benign. The sensitivity, specificity, and positive predictive value of PET for all hepatic lesions was 82%, 25%, and 96% compared with 63%, 50%, and 96% for abdominal ultrasound, 71%, 50%, and 97% for CT-scan, and 83%, 57%, and 97% for MRI-scan. In 23 of 50 patients 24 extrahepatic lesions were identified. In these patients the sensitivity and specificity of PET—compared to abdominal ultrasound, CT-scan, and MRI-scan for all extrahepatic lesions—was 63% and 60%, 29% and 25%, 47% and 50% and 40% and 50%, respectively. The findings on PET scan had a direct impact on operative management in nine patients (18%).Conclusions Our series demonstrates good sensitivity and specificity for the detection of primary and secondary liver lesions which is superior to ultrasound and CT scan but not to MRI scan. The main value of PET scan consists in the detection of extrahepatic tumor (64%). Due to better detection of extrahepatic tumor, FDG-PET is a very useful addition to the currently used anatomically-based images in all cases of advanced tumor spread with high risk of extrahepatic tumor.     

Sarcoidosis Occurring After Lymphoma: Report of 14 Patients and Review of the Literature

Sarcoidosis is a granulomatous disease that most frequently affects the lungs with pulmonary infiltrates and/or bilateral hilar and mediastinal lymphadenopathy. An association of sarcoidosis and lymphoproliferative disease has previously been reported as the sarcoidosis-lymphoma syndrome. Although this syndrome is characterized by sarcoidosis preceding lymphoma, very few cases of sarcoidosis following lymphoma have been reported. We describe the clinical, biological, and radiological characteristics and outcome of 39 patients presenting with sarcoidosis following lymphoproliferative disease, including 14 previously unreported cases and 25 additional patients, after performing a literature review. Hodgkin lymphoma and non-Hodgkin lymphoma were equally represented. The median delay between lymphoma and sarcoidosis was 18 months. Only 16 patients (41%) required treatment. Sarcoidosis was of mild intensity or self-healing in most cases, and overall clinical response to sarcoidosis was excellent with complete clinical response in 91% of patients. Sarcoidosis was identified after a follow-up computerized tomography scan (CT-scan) or ¹⁸fluorodeoxyglucose-positron emission tomography/computerized tomography (¹⁸FDG-PET/CT) evaluation in 18/34 patients (53%). Sarcoidosis is therefore a differential diagnosis to consider when lymphoma relapse is suspected on a CT-scan or ¹⁸FDG-PET/CT, emphasizing the necessity to rely on histological confirmation of lymphoma relapse.     

A case of SAPHO (synovitis-acne-pustulosis-hyperostosis-osteomyelitis) syndrome in which [<Superscript>18</Superscript>F]fluorodeoxyglucose positron emission tomography was useful for differentiating from multiple metastatic bone tumors

We report the case of a 50-year-old Japanese woman with SAPHO (synovitis-acne-pustulosis-hyperostosis-osteomyelitis) syndrome. Radiographs showed osteosclerosis of the cervical and lumbar vertebrae, as well as osteosclerosis and osteolysis of the right femoral neck, resembling multiple metastatic bony lesions. Arriving at a diagnosis required hematological and imaging tests. Whole-body bone scintigraphy identified diffuse uptake from the lower cervical vertebrae to the lumbar vertebrae and marked uptake in the right femoral neck. However, with [¹⁸F]fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG-PET) scanning, abnormal [¹⁸F]FDG uptake was not detected in cervical and lumbar spine, or in the femoral neck. Bone biopsy showed signs of chronic nonspecific inflammation, rather than tumor or infection. Based on these findings, the patient was diagnosed with SAPHO syndrome unaccompanied by skin lesions, and administration of non-steroidal anti-inflammatory drugs provided pain relief.     

Physiopathologie de la maladie de Behçet

Although the precise pathogenesis and etiology of Behçet's disease (BD) still remains unknown, current evidence suggests that inflammatory reaction in BD arises from disruption of homeostasis in genetically susceptible individuals, resulting in altered innate and adaptive immunity responses, pathogenic T cell activation in the peripheral blood, and in inflammatory sites. Association with HLA-B51 is known as the strongest genetic susceptibility factor for BD. Recent GWAS (genome-wide association studies) have confirmed this relationship, and reported new susceptibility genes (IL-10, IL-23R, IL-12RB2) for the disease. A triggering infectious agent could operate through molecular mimicry, and the disease could subsequently be perpetuated by an abnormal immune response to an auto-antigen in the absence of ongoing infection. Several potential bacteria have been investigated but the most commonly implicated microorganism is Streptococcus sanguis. Recent data have showed that the T cell homeostasis perturbation consisted mainly of Th1 and Th17 expansions, while regulatory T cell response was suppressed. Cytokine such as IL-17, IL-23 and IL-21 play a significant role in the pathogenesis of BD. Inflammatory cells within BD inflammatory lesions include mostly neutrophils, CD4⁺ T cells, and cytotoxic cells. Lastly, endothelium dysfunction has been clearly established. This improved understanding of the pathophysiology of BD will certainly lead to the development of new therapeutic agents, potentially more effective than current therapy. In this review, we have studied the etiopathogenesis of BD in the light of recent advances.     

Positron emission tomography in esophageal cancer

Positron emission tomography (PET), a functional imaging modality, has provided the transition between the research environment and the clinical environment over the last 10 years. Its primary use is in the field of oncology, where it is being increasingly used in the management of several tumor types including esophageal cancer. ¹⁸F-Fluorodeoxyglucose PET (FDG-PET) scans may also be used to distinguish between benign and malignant tumors, to identify different stages of tumor spread, to assess for tumor recurrence, and monitor the response to therapy of malignant diseases. This review aims to outline the current and future roles of PET scanning in the field of esophageal cancer.     

Caractéristiques cliniques,paracliniques et profil évolutif de l’atteinte aortique de la maladie de Horton : à propos de 26 cas d’aortite parmi 63 cas de maladie de Horton

Purpose

Aortic involvement that occurs in temporal arteritis is probably underestimated because it is usually asymptomatic. The characteristics of giant cell arteritis with aortic involvement are still poorly described and the relationship between aortitis and vascular outcome of the disease has not been clearly delineated. The objective of this retrospective study of 63 patients with giant cell arteritis, including 26 with aortic involvement, was to compare the features of patients with and without aortitis, and to assess the contribution of CT-scan and FDG-PET-scan in screening for vascular disease, monitoring, and therapeutic management of patients.

Methods

This retrospective study was conducted in the internal medicine department of the university hospital in Marseille, France, from January 1, 2005 to September 30, 2011. Patients had at least three out of the five American College of Rheumatology criteria for temporal arteritis and aortic involvement was investigated in all patients using CT-scan. Aortic wall thickness greater or equal to 3 mm was considered to be abnormal.

Results

Of 63 patients diagnosed with giant cell arteritis, 26 (41.3%) had aortic involvement diagnosed by aortic CT-scan. Age at diagnosis was significantly younger (66.8 vs 73.8 years; P = 0.002) in the group with aortitis. Inflammatory dorsal and low back pain, signs of vascular disease of the upper limbs (P = 0.009), and higher level of acute phase reactants were associated with aortitis. Aneurysmal lesions of the aorta were significantly more frequent in the group with aortitis. Twenty patients had both aortic CT-scan and FDG-PET-scan. For patients in whom aortic involvement was not demonstrated with CT-scan, FDG-PET-scan was always non-contributive. With corticosteroids, aortitis resolved within 6 months in all patients as evaluated by aortic CT-scan. However, aortitis persisted in 80% of cases at 6 months when evaluated with FDG-PET-scan, and in 66% of cases at 12 months, without influencing the treatment.

Conclusion

This case series shows no specific features of aorta and its main roots involvement in giant cell arteritis, justifying a systematic screening by CT-scan. The high frequency of this arterial involvement could help physicians in the diagnosis of giant cell arteritis. Aortitis seems to be associated with vascular complications as highlighted by the frequency of aortic aneurysm and a case of early aortic dissection. Finally, the role of PET-CT-scan for screening vascular disease and therapeutic monitoring remains to be clarified.     

Gastric GIST malignancy evaluated by 18FDG-PET as compared with EUS-FNA and endoscopic biopsy

Objective. The usefulness of ¹⁸F-fluoro-2-deoxyglucose positron emission tomography (¹⁸FDG-PET), whose high rate of FDG accumulation indicates high metabolism and malignant potential, has already been reported. The aims of this study were to evaluate the malignancy of primary gastrointestinal stromal tumour (GIST) in the stomach by ¹⁸FDG-PET and to correlate the FDG uptake values with known risk factors as determined by histology after EUS-guided fine needle aspiration (EUS-FNA) or endoscopic biopsy. Material and Methods. Of 29 patients with histologically proven GI-mesenchymal tumours, 21 with gastric GISTs underwent ¹⁸FDG-PET. Tumour size, mitotic index, Ki-67 labelling index (LI) and cellularity of the tumour tissue were compared with the standardized uptake value (SUV) of FDG. Results. Strong correlations were found between the SUV of FDG and EUS size, and mitotic index of EUS-FNA specimens (tumour size versus SUV, p=0.004, r=0.542; number of mitotic cells versus SUV, p=0.0078; n=21). Moreover, we examined the association between SUV and risk categories based on EUS-FNA findings using ROC curves. The cut-off values of FDG SUV were 2.2, 4.2 and 6.5 for the very low-, low-, intermediate- and high-risk groups, respectively. Conclusions. ¹⁸FDG-PET may be used to assess malignancy of GISTs. This image modality helps us determine the management strategy for these patients and complements the information on the biological behaviour and cellular proliferation of the tumours.     

Prise de poids,démence et syndrome cérébelleux sensible à la doxycycline : un probable nouveau cas lié à T. whipplei

Introduction

Whipple's disease is a rare infectious disease due to Tropheryma whipplei, a bacterium rarely causing severe localized neurological infection (only 25 cases reported in the literature), which are more often diagnosed by a positive T. whipplei PCR performed on cerebrospinal fluid.

Case report

We report the third case of progressive dementia associated with obesity and ataxia in a 52-year-old man. Classic laboratory results performed to identify the etiology of the clinical features were non-contributive: only a saliva T. whipplei PCR was strongly positive and the Western blot serology has detected an asymptomatic carriage profile. The ¹⁸FDG-PET highlighted a frontal area hypometabolism. An antibiotic treatment by doxycycline allowed a partial regression of the neurological manifestations, a weight loss and a significant improvement of the ¹⁸FDG frontal hypometabolism.

Conclusion

Progressive dementia associated with ataxia and obesity is a new clinical syndrome caused by T. whipplei. Antibiotic test by doxycycline can help to the diagnosis and ¹⁸-FDG could facilitate the follow-up.     

Use of radioactive substances in diagnosis and treatment of neuroendocrine tumors

Abstract

Radionuclides are needed both for nuclear medicine imaging as well as for peptide-receptor radionuclide therapy (PRRT) of neuroendocrine tumors (NET). Imaging is important in the initial diagnostic work-up and for staging NETs. In therapy planning, somatostatin receptor imaging (SRI) is used when treatment is targeted at the somatostatin receptors as with the use of somatostatin analogues or PRRT. SRI with gamma camera technique using the tracer ¹¹¹In-DTPA-octreotide has for many years been the backbone of nuclear imaging of NETs. However, increasingly PET tracers for SRI are now used. ⁶⁸Ga-DOTATATE, ⁶⁸Ga-DOTATOC and ⁶⁸Ga-DOTANOC are the three most often used PET tracers. They perform better than SPECT tracers and should be preferred. FDG-PET is well suited for visualization of most of the somatostatin receptor-negative tumors prognostic in NET patients. Also ¹¹C-5-HTP, ¹⁸F-DOPA and ¹²³I-MIBG may be used in NET. However, with FDG-PET and somatostatin receptor PET at hand we see limited necessity of other tracers. PRRT is an important tool in the treatment of advanced NETs causing complete or partial response in 20% and minor response or tumor stabilization in 60% with response duration of up to 3 years. Grade 3–4 kidney or bone marrow toxicity is seen in 1.5% and 9.5%, respectively, but are completely or partly reversible in most patients. ¹⁷⁷Lu-DOTATATE seems to have less toxicity than ⁹⁰Y-DOTATOC. However, until now only retrospective, non-randomized studies have been performed and the role of PRRT in treatment of NETs remains to be established.     

Atteintes rénales de la sarcoïdose

Sarcoidosis is a chronic multisystemic inflammatory disorder of unknown etiology, characterized by the presence of non-necrotizing epithelioid and giant cell granulomas. Various renal manifestations have been reported in patients with sarcoidosis. Disorders of bone and mineral metabolism related to the overexpression of 25-hydroxyvitamin-D1α-hydroxylase by alveolar and granuloma macrophages are frequently associated with sarcoidosis. Hypercalcemia and hypercalciuria are a major cause of renal injury predisposing to pre renal azotemia, acute tubular necrosis, nephrolithiasis and nephrocalcinosis. Therapeutic management of hypercalcemia includes preventive measures (limited sunlight exposure, limited vitamin D and calcium intakes, and adequate hydration) and specific treatment in cases of severe hypercalcemia (corticosteroid therapy, chloroquine or ketoconazole). Granulomatous tubulointerstitial nephritis is the most common renal lesion associated with sarcoidosis leading to end stage renal disease in some patients. In these cases, interstitial fibrosis seems to appear early in the course of sarcoidosis and is a major prognostic factor requiring rapid corticosteroid therapy to reduce the risk of severe renal impairment. Membranous nephropathy seems to be the most frequent glomerular disease that may occur in association with sarcoidosis. Among kidney allograft recipients, the risk of recurrence of granulomatous tubulointerstitial nephritis is high and may have a negative impact on the graft survival.     

18F-FDG PET/CT imaging for a gastrointestinal mantle cell lymphoma with multiple lymphomatous polyposis

Multiple lymphomatous polyposis(MLP)is an uncommon type of gastrointestinal lymphoma characterized by the presence of multiple polyps along the gastrointestinal tract.Most of this entity is in fact considered the counterpart of gastrointestinal tract involvement for mantle cell lymphoma(MCL).To our knowledge,there have been no reports on[fluorine-18]-fluorodeoxy-glucose(18F-FDG)-positron emission tomography(PET)/computed tomography(CT)imaging for gastrointestinal MCL with MLP.We present the results of 18F-FDG PET/CT imaging in a patient with gastrointestinal tract involvement of MCL showing continuous MLP from the stomach to the rectum and intestinal intussusception.FDG-PET/CT findings were false negative in typical MLP spreading widely over the gastrointestinal tract,but uptake was noted in large lesions with deep infiltration considered atypical as MLP.On FDG-PET/CT imaging,the Ki-67proliferative index,which is a cell proliferation marker,showed neither correlation with the presence of uptake nor the maximum standardized uptake value.     

Sarcoïdose vertébrale. Évolution spontanément favorable : une observation et revue de la littérature

Introduction

The prevalence of vertebral sarcoidosis is highly variable (1 to 36% of reported case series). Because of limited clinical expression, its frequency is probably underestimated. Its proper management is not clearly defined.

Case report

A 42-year-old woman who had a past medical history of cutaneous and pulmonary sarcoidosis presented with low back pain that was refractory to usual medical treatment. A diagnosis of vertebral localisation of sarcoidosis was considered on the history of proven sarcoidosis, radiological features, and the absence of evidence of an alternative diagnosis. In the absence of other clinical or biological evidence of active sarcoidosis, a simple follow-up was planned. MRI control at 1 year showed the resolution of vertebral sarcoidosis lesions.

Conclusion

Spontaneous regression is a possible outcome of vertebral sarcoidosis. Initiation of a specific treatment should be discussed in the absence of other visceral involvement.     

Sarcoid uveitis: Diagnostic and therapeutic update

Uveitis is a common (20-50%) and early manifestation of sarcoidosis. Typical sarcoid uveitis presents with bilateral mutton fat keratic precipitates, iris nodules, and anterior and posterior synechia. Posterior involvement includes vitreitis, vasculitis and choroidal lesions. Long-term complications are common, and cystoid macular edema is the most important and sight-threatening consequence. Diagnostic work-up of sarcoidosis usually includes chest radiography or computed tomography scan, bronchoscopy with bronchoalveolar lavage, angiotensin converting enzyme, lysozyme, gallium scintigraphy and biopsy. The gold standard for the diagnosis of sarcoidosis should be obtained with histologic examination. However, an international workshop has recently established diagnostic criteria of “intraocular sarcoidosis” (sarcoidosis uveitis) on the basis of a combination of suggestive ophthamological findings and laboratory tests, when biopsy is not performed or is negative. More recent techniques such as PET-scan and endoscopic ultrasound-guided fine-needle biopsy of intrathoracic nodes should be assessed in future prospective studies. Corticosteroids are the mainstay of treatment. Anterior and unilateral intermediate or posterior uveitis are usually treated with topical corticosteroids. Systemic corticosteroids are indicated in uveitis not responding to topical corticosteroids or in the presence of bilateral posterior involvement, especially with macular edema and occlusive vasculitis. In 5 to 20% of the patients who are corticosteroids resistant or require an unacceptable dose to maintain remission, additional immunosuppression is used, including methotrexate, leflunomide and mycophenolate mofetil. As in systemic sarcoidosis, infliximab has been recently suggested for refractory or sight threatening disease.     

Y a-t-il une essence de la médecine?

Introduction. — Medical practice has to move from a one-on-one relationship to consensual organization of the overall management of patients. Issues at stakes and potential consequences following such changes are discussed.Exegesis. — The evolution of medical practice is introduced as a necessity resulting from both improvements in medical technology and economical pressure. Utilitarian and procedural doctrines are promoted, taking the place of ethical bases. The one-on-one relationship evidences two essential aspects: there is often more in the request made to the practitioner than just the expression of an immediate need, and the patient is not only an organism. Both aspects reflect the specificity of human beings. There is a danger that they will disappear, as they are not included in the definition of “useful”, which in fact controls current choices.Conclusion. — Medical practice is radically modifying its own basis. Practitioners who acknowledge these changes should be aware of their cost.     

<Superscript>18</Superscript>F-FDG PET in the detection of extrahepatic metastases from hepatocellular carcinoma

Background Positron emission tomography (PET) with ¹⁸F-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) is useful in detecting distant metastases from a variety of malignancies. However, its efficiency in detecting distant metastases from hepatocellular carcinoma (HCC) has not been investigated. The aim of this study was to evaluate the usefulness of ¹⁸F-FDG PET for the detection of extrahepatic metastases from HCC.Methods Nineteen patients suspected of having extrahepatic HCC underwent ¹⁸F-FDG PET. Fourteen patients (group A) had extrahepatic lesions, which were detected by conventional studies. In five patients (group B), conventional imaging showed no extra- or intrahepatic lesions, but the tumor marker levels were elevated. The PET results were compared with those obtained by histopathology or by clinical follow-up.Results The detection rate of ¹⁸F-FDG PET was 83% (24 of 29 metastases) for extrahepatic metastases larger than 1cm in greatest diameter and 13% (1 of 8 metastases) for lesions less than or equal to 1cm. PET revealed two bone metastases not depicted by bone scan, and detected the nodal metastasis and intestinal metastases inconclusive on computed tomography. Extrahepatic lesions were resected in 5 patients of group A on the basis of PET findings. In all patients of group B, PET results were true negative for extrahepatic metastases, but HCCs were detected in the liver within 4 months in 4 patients. These were no false-positive lesions in either group.Conclusions This preliminary study suggested that ¹⁸F-FDG PET could provide additional information and contribute to the management of HCC patients suspected of having extrahepatic metastases.     

Manifestations neurologiques de la maladie de Behçet

Neurological manifestations of Behçet's disease (BD) occur in 5.3 to more than 50% of patients. They are divided into two major forms: “parenchymal” lesions, which include mainly meningoencephalitis as opposed to “extra-parenchymal” lesions (i.e. cerebral venous thrombosis and arterial aneurysms). Myelitis or peripheral neuropathy is exceptional. The neuro-Behçet syndrome (NBS) should be considered in the setting of neurological manifestations, particularly headache and pyramidal signs, in a young man diagnosed with BD. However, its recognition may be difficult when neurological manifestations are the presenting features of BD (one third of cases), and requires a thorough knowledge of clinical manifestations and morphological lesions. Thus, parenchymal NB lesions classically exhibit inflammatory characteristics on MRI and are located at the meso-diencephalic junction and in the brainstem, rarely with a supratentorial extension. Meningitis is not systematically associated, and may be absent in about 30% of cases. The pathogenesis of these lesions is incompletely understood, but inflammatory infiltrates include mainly neutrophils and activated T cells (mainly Th17). Differential diagnoses include infectious diseases (herpes, listeria, tuberculosis), and inflammatory diseases (i.e. multiple sclerosis and sarcoidosis). A prompt recognition of NBS should lead to initiate adequate therapies in order to limit the risk of sequelae, relapses or death.     

Les leucémies à grands lymphocytes granuleux : de la clinique à la physiopathologie

Large granular lymphocyte leukemia (LGL) is a hematologic disorder characterized by a monoclonal expansion of large lymphocytes containing azurophilic granules with a T CD3⁺CD57⁺ or Natural Killer (NK) CD3^–CD56⁺ phenotype. The World Health Organization (WHO) classification identifies three entities: the T LGL, the chronic lymphoproliferative disorder of NK-cells, and the aggressive NK-cell leukemia. T LGL and chronic lymphoproliferative disorder of NK-cells are indolent diseases frequently associated with cytopenias and a wide spectrum of auto-immune manifestations. Neutropenia can lead to recurrent bacterial infections, which represent an indication of initiating a treatment in most of the cases. Immunosuppressive therapies are usually used in this context. In contrast, aggressive NK-cell leukemia follows a fulminant course with a poor prognosis because patients are refractory to most of the treatments. There is now a considerable interest in the pathophysiology of the disease with the perspective of new therapeutic options.