Kikuchi Disease Mimicking Malignant Lymphoma on FDG PET/CT

Analysis of the clinical manifestations and 18F-FDG PET-CT findings in 40 patients with histiocytic necrotizing lymphadenitis

Histiocytic necrotizing lymphadenitis (HNL) is a rare, benign, and self-limiting inflammatory disease that mainly involves the lymph nodes. There is a lack of large sample studies concerning the clinical manifestations and imaging features of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) of HNL.The clinical symptoms, laboratory examination results, 18F-FDG PET/CT imaging features, and treatment outcome were investigated in this retrospective study.A total of 40 HNL patients were recruited. The onset age was between 14 and 65 years, with a median of 25 years. The white blood cell count was 3.9 (2.9, 7.1) × 109/L, C-reactive protein level was 20.2 (6.6, 63.8) mg/L, erythrocyte sedimentation rate was 29.0 (18.0,45.0) mm/h, and ferritin was 616.5 (205.6, 2118.1) ng/mL. An abnormal liver function was observed in 23 patients. 18F-FDG PET-CT showed that an abnormal lymph node metabolism was observed in 38 patients, among which the highest 18F-FDG maximal standard uptake value (SUVmax) of the lymph nodes ranged between 3.4 and 41.9; the nodes were mainly distributed in the neck and axilla regions. Meanwhile, a total of 2502 lymph nodes (721 lymph nodes with a short axis greater than 10 mm) were found in the 38 patients, including 1837 lymph nodes with an 18F-FDG SUVmax ≥ 2.5. The 18F-FDG SUVmax of the spleen ranged from 2.5 to 9.2 in 20 patients, while that of central and peripheral bone marrow ranged from 2.7 to 36.0 in 30 patients. After follow-up for an average period of 1 month, the symptoms improved after prednisone treatment.HNL often occurs in adolescents. Scanning with 18F-FDG PET/CT showed that most patients had multiple involved lymph nodes that were hypermetabolic, and only few lymph nodes are enlarged. Besides, the spleen or central and peripheral bone marrow could sometimes be hypermetabolic. Glucocorticoid treatment for the HNL patients is effective.

Positron emission tomography/computed tomography hypermetabolism of Kikuchi-Fujimoto disease mimicking malignant lymphoma: a case report and literature review

Kikuchi–Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a benign, self-limiting inflammatory disorder of unknown etiology and pathogenesis. This report presents a rare case involving a man with ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) hypermetabolism caused by KFD mimicking malignant lymphoma. The PET/CT maximum intensity projection showed multiple hypermetabolic lymphadenopathies and homogeneous FDG uptake in the bone marrow and spleen. Malignant lymphoma was initially suspected. The patient then underwent excision biopsy of one enlarged right cervical lymph node that was selected because it showed the highest FDG uptake in PET/CT, and examination of this biopsy specimen confirmed the diagnosis of KFD. PET/CT is useful for assessing the general condition of patients and can help to select lymph nodes for excision biopsy based on the highest FDG uptake. However, KFD can predispose to localized FDG uptake and limit the specificity of PET/CT by mimicking malignancy. Thus, positive results of PET/CT should be interpreted with caution.

Systemic Lupus Erythematosus Associated Pitfalls on 18F-FDG PET/CT: Reactive Follicular Hyperplasia, Kikuchi-Fujimoto Disease, Inflammation and Lymphoid Hyperplasia of the Spleen Mimicking Lymphoma

Systemic lupus erythematosus (SLE) is associated with a variety of inflammatory processes that can affect the lymph nodes, brain, kidneys, and spleen. We present two patients with SLE in whom SLE-associated conditions complicated interpretation of ¹⁸F-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) imaging of the lymph nodes and the spleen. The imaging findings mimicked lymphoma, but histopathological evaluation showed benign processes including reactive follicular hyperplasia in the lymph nodes, Kikuchi-Fujimoto disease in perisplenic lymph nodes, and inflammatory changes and lymphoid hyperplasia in the spleen.

Kikuchi Disease with Generalized Lymph Node, Spleen and Subcutaneous Involvement Detected by Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

Kikuchi-Fujimoto disease, known as Kikuchi disease, is a rare benign and self-limiting disorder that typically affects the regional cervical lymph nodes. Generalized lymphadenopathy and extranodal involvement are rare. We report a rare case of a 19-year-old female with a history of persistent fever, nausea, and debilitating malaise. Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) revealed multiple hypermetabolic generalized lymph nodes in the cervical, mediastinum, axillary, abdomen and pelvic regions with diffuse spleen, diffuse thyroid gland, and focal parotid involvement, bilaterally. In addition, subcutaneous lesions were noted in the left upper paraspinal and occipital regions. An excisional lymph node biopsy guided by 18F-FDG PET/CT revealed the patient's diagnosis as Kikuchi syndrome.

A roadmap for fever of unknown origin in children

Fever of unknown origin (FUO) in adults is conventionally defined by the occurrence of body temperatures above 38.3 degrees C (101 degrees F) for a period of 3 weeks without any identified etiology after a period of 1-week hospitalization. The issue of FUO in pediatrics is rather hazy and still represents a challenging diagnostic dilemma. Most of the available data are limited to nationwide cohorts of patients of any age. The major difficulty in establishing a diagnosis is that the characteristic features rendering specific disorders clinically recognizable are absent or subtle, hence only a painstaking questioning on family background may elicit the correct investigative path. No diagnostic algorithms are actually available and clinicians must rely on a very careful step-by-step evaluation of the single patient. The need for invasive diagnostic techniques should be closely taken into consideration when laboratory tests or simple imaging procedures fail to discern the origin of FUO. Fevers with no reasonable explanation and no localizing signs often conceal different common diseases in children, which tend to display an unusual or atypical pattern. The principal causes behind FUO in pediatric age remain infections, followed by collagen vascular diseases and neoplastic disorders, although most children with malignancies present other systemic signs or suggestive laboratory abnormalities. The possibility of autoinflammatory syndromes, drug fever, and factitious fever should also be taken into account.

18F-FDG PET/CT findings in patients with Kikuchi disease

PURPOSE

Kikuchi disease (KD) is a benign and self-limited syndrome characterized by cervical lymphadenopathy. This study evaluated 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) findings in patients with KD and analyzed their imaging features.

PATIENTS, MATERIAL, METHODS

We evaluated the FDG PET/CT findings of 22 patients (14 men, 8 women) with KD, ranging in age from 9 to 73 years. All patients had been diagnosed based on the pathological findings of biopsy. We examined the locations, metabolic activity and size of hypermetabolic lymph nodes (LNs) on FDG PET/CT imaging with medical history including laboratory results.

RESULTS

Among the 22 patients, we identified 619 hypermetabolic LNs which had maximum standard uptake value (SUVmax) above 3.0. The 16 patients were studied with FDG PET/CT to identify the cause of fever, another 5 patients for their neck masses, and the remaining patient for his left inguinal mass. Hypermetabolic LNs were noted in neck (18 bilaterally, 2 right, 1 left) of 21 patients, axilla of 10, mediastinum of 9, abdomen of 17, pelvis of 6, and inguinal area of 3. The SUVmax of FDG uptake in affected LNs by patient base analysis were 6.2-29.4. Of the 619 hypermetabolic LNs identified, 440 LNs (71.1%) were less than 10 mm in their short axis determined by CT, and were occasionally aggregated. No patient showed solid organ hypermetabolic lesion in FDG PET/CT.

CONCLUSION

Kikuchi disease could present multiple hypermetabolic LNs in body on FDG PET/CT. Based on the physical findings, consideration of the generalized distribution of the relatively small-sized hypermetabolic LNs, FDG PET/CT may be useful as a diagnostic tool in cases of Kikuchi disease.

Kikuchi-fujimoto disease: a case report and literature review

Case. 38-year-old lady was referred to the ENT clinic with history of right-sided facial pain, otalgia, and odynophagia. Clinical examination revealed enlarged right-sided lymph nodes in the neck. Further radiological scans showed a mass near the carotid and enlarged level V lymph nodes. Lymphoma was initially suspected. Fine-needle aspiration and excision biopsy were undertaken. Histological analysis later suggested Kikuchi-Fujimoto disease, also known as histiocytic necrotising lymphadenitis. Literature Review. Kikuchi-Fujimoto disease (KFD) was described in 1972 as lymphadenitis with focal proliferation of reticular cells accompanied by numerous histiocytes and extensive nuclear debris. KFD, frequently found in East Asian countries, is rare in the UK. No definite aetiology of KFD is known despite autoimmune and infection factors being suggested. The diagnostic hallmark is histological findings from lymph nodes. Malignancy should be excluded. This condition is mainly self-limiting; hence, management is limited to supportive care. Steroid therapy could be used in severe cases. KFD is relatively unknown in the UK and this case report aims to highlight its occurrence in our population.

Kikuchi-Fujimoto disease: PET/CT assessment of a rare cause of cervical lymphadenopathy

PURPOSE

Kikuchi-Fujimoto disease (KFD), formerly called subacute necrotizing lymphadenitis, is a rare cause of cervical lymphadenopathy. The purpose of this study was to evaluate the usefulness of FDG PET/CT for distinguishing KFD from non-Hodgkin lymphoma (NHL).

MATERIALS AND METHODS

Twenty-two patients with cervical lymphadenopathy (8 with KFD and 14 with NHL) underwent CT and FDG PET/CT scans to examine the cervical lymphadenopathy. Regional values of FDG uptake were evaluated using the standardized uptake value (SUV) and partial volume corrected SUV (corSUV) based on the count recovery coefficient. Tumor size (mm), SUV, and corSUV were compared among KFD, indolent NHL, and aggressive NHL.

RESULTS

KFD lesions tended to be smaller (13.8 ± 5.4 mm) than those of indolent (25.4 ± 11.8) and aggressive (29.7 ± 18.8) NHL, whereas there were no significant differences in size. As for SUV, a significant difference was observed only between indolent and aggressive (6.4 ± 1.5 and 17.3 ± 9.3, P < 0.05) NHL; however, KFD showed a significantly greater corSUV (23.8 ± 10.6) as compared with indolent NHL (9.2 ± 5.1, P < 0.05), which did not show a significant difference from aggressive NHL (21.4 ± 10.2). FDG PET/CT detected thoracoabdominal lesions in 2 patients (25%) with KFD.

CONCLUSIONS

KFD shows high FDG uptake for size, which may reflect the pathologic characteristics, including necrotizing lymphocytes and numerous histiocytes (macrophages) surrounding small necrotic foci. FDG PET/CT will be useful for detecting noncervical lesions of KFD and distinguishing KFD from NHLs using both SUV and corSUV.

[Kikuchi disease and lupus: case report, literature review and FDG PET/CT interest]

Kikuchi disease is a rare entity characterized by lymphadenopathy and fever. Pathology study of lymph node biopsies provides the diagnosis. The disease course is favorable. The disease can occur isolated, or associated with other pathologies including lupus or mixed connective tissue disease. We report a case of Kikuchi disease in a 35-year-old woman, occurring 12 years after the diagnosis of overlap syndrome with antiphospholipid antibodies. The patient was given prednisone 25mg per day and long-term hydroxychloroquine. FDG PET/CT showed FDG-avidity nodular masses. After bolus corticosteroid therapy, outcome was favorable with disappearance of metabolic hyperactivity on the FDG PET/CT. The bolus prednisone treatment could then be discontinued. In the 61 cases of Kikuchi disease and lupus associations previously published, Kikuchi disease was diagnosed after lupus in only 13 % of the observations. In these cases, use of FDG PET/ CT was not reported. For us, FDG PET/CT was useful for diagnosis, for choosing the biopsy site and for follow-up.

Disseminated Kikuchi disease associated with hemophagocytic syndrome in an infant: whole-body MRI

We report a case of disseminated Kikuchi disease (KD) associated with Hemophagocytic syndrome (HS) in a 9-month-old boy with recurrent fever and tender cervical and inguinal lymphadenopathy. Disseminated necrotizing lymphadenopathies can be observed on whole-body MR imaging.

Kikuchi-Fujimoto disease with spontaneous subdural hematoma in a middle-aged Hispanic male

Kikuchi-Fujimoto disease (KFD) is an uncommon disorder that usually presents in young adults of Asian descent with fever and cervical lymphadenopathy. Clinically, this disease is often misdiagnosed as lymphoma or tuberculosis, and biopsy is needed for confirmation. The authors report an unusual case of KFD in a Hispanic male presenting with a subacute subdural hematoma, whose care was complicated by extranodal features not typically associated with KFD. The clinical, histopathologic, and radiographic manifestations of KFD are discussed.