Role of F-18 FDG PET/CT in assessing IgG4-related disease with inflammation of head and neck glands

Executive summary of the consensus document on hypophysitis of the Neuroendocrinology Area of Knowledge of the Spanish Society of Endocrinology and Nutrition

The term hypophysitis is used to designate a heterogeneous group of pituitary conditions characterized by the presence of inflammatory infiltration of the adenohypophysis, neurohypophysis, or both. Although hypophysitis are rare disorders, the most common in clinical practice is lymphocytic hypophysitis, a primary hypophysitis characterized by lymphocytic infiltration, which predominantly affects women. Other forms of primary hypophysitis are associated with different autoimmune diseases. Hypophysitis can also be secondary to other disorders such as sellar and parasellar diseases, systemic diseases, paraneoplastic syndromes, infections, and drugs, including immune checkpoint inhibitors. The diagnostic evaluation should always include pituitary function tests and other analytical tests based on the suspected diagnosis. Pituitary magnetic resonance imaging is the investigation of choice for the morphological assessment of hypophysitis. Glucocorticoids are the mainstay of treatment for most symptomatic hypophysitis.

18F-fluorodeoxyglucose PET and PET/computed tomography for the evaluation of immunoglobulin G4-related disease: a systematic review

BACKGROUND

In the last years, 18F-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) has demonstrated its utility for the evaluation of immunoglobulin G4 (IgG4)-related disease (IgG4RD). The studies are, however, really heterogeneous and different. The aim of this review is, therefore, to analyze the diagnostic performance of 18F-FDG PET and PET/CT for the assessment of IgG4RD.

METHODS

A wide literature search of the PubMed/MEDLINE, Scopus, Embase and Cochrane library databases was made to find relevant published articles about the diagnostic performance of 18F-FDG PET or PET/CT for the evaluation of IgG4RD.

RESULTS

The comprehensive computer literature search revealed 779 articles. On reviewing the titles and abstracts, 756 articles were excluded because the reported data were not within the field of interest. Twenty-three studies were included in the review.

CONCLUSION

Despite some limitations that affect our review, 18F-FDG PET or PET/CT demonstrated the ability to assess IgG4RD both at initial evaluation and after therapy. In general, no correlation between PET/CT parameters and IgG4 serum levels has been reported. A possible role for 18F-FDG PET/CT to drive differential diagnosis with other disease is starting to emerge.

Hypophysitis, the Growing Spectrum of a Rare Pituitary Disease

Hypophysitis is defined as inflammation of the pituitary gland that is primary or secondary to a local or systemic process. Differential diagnosis is broad (including primary tumors, metastases, and lympho-proliferative diseases) and multifaceted. Patients with hypophysitis typically present with headaches, some degree of anterior and/or posterior pituitary dysfunction, and enlargement of pituitary gland and/or stalk, as determined by imaging. Most hypophysitis causes are autoimmune, but other etiologies include inflammation secondary to sellar tumors or cysts, systemic diseases, and infection or drug-induced causes. Novel pathologies such as immunoglobulin G4-related hypophysitis, immunotherapy-induced hypophysitis, and paraneoplastic pituitary-directed autoimmunity are also included in a growing spectrum of this rare pituitary disease. Typical magnetic resonance imaging reveals stalk thickening and homogenous enlargement of the pituitary gland; however, imaging is not always specific. Diagnosis can be challenging, and ultimately, only a pituitary biopsy can confirm hypophysitis type and rule out other etiologies. A presumptive diagnosis can be made often without biopsy. Detailed history and clinical examination are essential, notably for signs of underlying etiology with systemic manifestations. Hormone replacement and, in selected cases, careful observation is advised with imaging follow-up. High-dose glucocorticoids are initiated mainly to help reduce mass effect. A response may be observed in all auto-immune etiologies, as well as in lymphoproliferative diseases, and, as such, should not be used for differential diagnosis. Surgery may be necessary in some cases to relieve mass effect and allow a definite diagnosis. Immunosuppressive therapy and radiation are sometimes also necessary in resistant cases.

The prevalence of extra-salivary gland complications in immunoglobulin G4-related sialadenitis

OBJECTIVES

To estimate the prevalence of extra-glandular lesions in patients with immunoglobulin G4-related sialadenitis (IgG4-RS).

METHODS

Six electronic databases (PubMed, EMBASE, Science Direct, Scopus, Web of Science, and China National Knowledge Infrastructure) were systematically searched from the date of inception of each database to March 2021. The Strengthening the Reporting of Observational Studies in Epidemiology statement was used to conduct methodological quality assessment, and a random-effect meta-analysis model was applied to estimate the prevalence. Publication bias was visually assessed using a funnel plot and calculated via Begg's and Egger's tests. The Stata 15 software was used to perform data analysis.

RESULTS

A total of 43 articles comprising 1,864 patients with IgG4-RS were considered to be eligible for this study. The pooled prevalence of extra-salivary gland lesions in IgG4-RS was 76.53% with a confidence interval (CI) of (69.39%, 83.04%). A higher prevalence was associated with studies published before or during 2015 (84.38%, CI [74.23%, 92.58%]) than those published after 2015 (68.55%, CI [58.44%, 77.88%]). Lacrimal gland involvement (54.68%, CI [45.61%, 63.60%]) and lymph node swelling (56.96%, CI [48.16%, 65.56%]) were the most frequent lesions.

CONCLUSIONS

Extra-glandular lesions were common in patients with IgG4-RS. More high-quality prospective studies with less heterogeneity are required to determine the accurate prevalence.

Imaging of IgG4-Related Disease in the Head and Neck: A Systematic Review, Case Series, and Pathophysiology Update

This systematic review aims to clarify and comprehensively detail the sometimes variable published imaging features as well as the pathogenesis, clinical diagnostic criteria, and treatment options of IgG4-Related Diseases (IgG4-RD) in the head and neck to aid the radiologist in diagnosing relapse and new sites of disease. A literature search in PubMed and EMBASE for reported cases of IgG4-RD was performed in December 2019. Case reports or series of IgG4-RD in the head and neck in adults that included sufficient imaging and pathology findings were included. This yielded 50 reports. IgG4-RD locations included the orbits, thyroid, pituitary gland, paranasal sinuses, salivary and parotid glands, larynx, pharynx, cervical lymph nodes, meninges, and skull base. Most lesions demonstrated non-specific homogenous CT attenuation, diffuse enhancement, isointense/low T2 signal intensity, and low T1 signal intensity. 6 cases from our institution followed previously reported imaging patterns.

Recurrent Immunoglobulin G4-Related Disease Shown on 18F-FDG and 68Ga-FAPI PET/CT

A 21-year-old man had been diagnosed with immunoglobulin G4-related disease (IgG4-RD) for 5 years, and the disease recurred 1 month ago. F-FDG PET/CT revealed intense FDG activity in the pituitary stalk, submandibular gland, pleura, pericardium, pancreas, liver, prostate, and multiple lymph nodes, which were considered the involvements of IgG4-RD. Ga-FAPI PET/CT also showed intense Ga-FAPI uptake in the above FDG-avid lesions except the lymph node involvement. Additionally, involvement in the lacrimal glands was detected by Ga-FAPI. The positive findings of Ga-FAPI in the current case highlighted that Ga-FAPI may have value in the evaluation of IgG4-RD.

Non-specific orbital inflammation: Current understanding and unmet needs

Non-specific orbital inflammation (NSOI) is a noninfectious inflammatory condition of the orbit. Although it is generally considered the most common diagnosis derived from an orbital biopsy, it is a diagnosis of exclusion, meaning that the diagnosis requires exclusion of a systemic process or another identifiable etiology of orbital inflammation. The clinical diagnosis of NSOI is ill-defined, but it is typically characterized by acute orbital signs and symptoms, including pain, proptosis, periorbital edema, chemosis, diplopia, and less commonly visual disturbance. NSOI poses a diagnostic and therapeutic challenge: The clinical presentations and histological findings are heterogeneous, and there are no specific diagnostic criteria or treatment guidelines. The etiology and pathogenesis of NSOI are poorly understood. Here we recapitulate our current clinical understanding of NSOI, with an emphasis on the most recent findings on clinical characteristics, imaging findings, and treatment outcomes. Furthermore, gene expression profiling of NSOI and its implications are presented and discussed.

A comparison of the features of fluorine-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) between IgG4-related disease with bilateral hilar lymphadenopathy and sarcoidosis

We aimed to show the differentiation of the degree and distribution on Fluorine-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) between patients with immunoglobulin G4-related disease (IgG4-RD) and sarcoidosis, though both diseases frequently show bilateral hilar lymphadenopathy (BHL). The clinical records were retrospectively reviewed in 25 patients with IgG4-RD with BHL and 15 patients with sarcoidosis (stage I–II) diagnosed at Shinshu University Hospital. All patients underwent FDG-PET at Aizawa Hospital from January 2004 to December 2015. The FDG accumulation pattern and maximum standardized uptake value (SUVmax) of the hilar lymph nodes were compared between the two groups. The IgG4-RD group (21 men; median age 69 years) showed a significant male predominance and older age compared with the sarcoidosis group (3 men, median age 55.4 years). The IgG4-RD group showed a significantly higher incidence of FDG accumulation in the lachrymal gland, submandibular gland, pancreas, prostate and periurethral and periarterial regions compared with the sarcoidosis group. In contrast, the sarcoidosis group showed a significantly higher incidence of FDG accumulation in the supraclavicular and abdominal lymph nodes, muscle and soft tissues compared with the IgG4-RD group. Furthermore, the SUVmax of the hilar lymph nodes was significantly higher in the sarcoidosis group (median 7.20) than in the IgG4-RD group (median 4.20, p=0.002). In conclusion, significant differences were observed in the FDG accumulation patterns and SUVmax values of the hilar lymph nodes between IgG4-RD with BHL and sarcoidosis, although both diseases develop through the lymphatic routes of the lungs and are frequently associated with BHL.

Clinical value of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography for interstitial lung disease and myositis in patients with dermatomyositis

¹⁸ F-Fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is usually used to screen malignancy in patients with dermatomyositis (DM). Additionally, it is well known that FDG-PET/CT provides valuable information for evaluating the activity of several inflammatory diseases, such as sarcoidosis, atherosclerosis, inflammatory bowel disease and rheumatoid arthritis. Therefore, the objective of this study was to evaluate the clinical usefulness of FDG-PET/CT for the detection of inflammatory lesions and disease activity of both myopathy and interstitial lung disease (ILD) in DM patients. We measured the maximum standardized uptake value (SUVmax) in the muscles and lungs in 22 DM patients, and compared with magnetic resonance imaging (MRI) and high-resolution computed tomography (HRCT) findings in the same muscle and lung regions as well as with clinical findings. We found that the location of increased FDG uptake was nearly consistent with the region of ILD and myositis detected by HRCT or MRI, respectively. There was a significant positive correlation between lung HRCT score and SUVmax in each lung. Serum Krebs von den Lungen-6 levels also revealed significant positive correlation with total SUVmax of right and left lungs. Regarding FDG-PET/CT and myopathy, total SUVmax in the muscles was significantly correlated with serum cytokeratin levels. Our results suggest that FDG uptake (SUVmax) might be useful for not only the detection of malignant tumors, but also the evaluation of the location and activity of ILD and myositis in DM patients.

Tumor long-axis diameter and SUVmax predict long-term responders in 90Y-ibritumomab tiuxetan monotherapy

90Y-ibritumomab tiuxetan (90Y-IT) is widely used, but the factors responsible for its optimal treatment effects are unknown. We enrolled 34 patients with relapsed indolent lymphoma treated with 90Y-IT monotherapy at Gunma University Hospital between 2003 and 2014 in the present study. Clinical data including computed tomography and 18-Fluoro-deoxyglucose positron emission tomography were retrospectively analyzed. The overall response rate and complete response rate were 91% and 82%, respectively. The median progression-free survival (PFS) and overall survival were 32 months and not reached, respectively. In univariate analysis, tumor long-axis diameter ≤ 2.5 cm, maximum standardized uptake value (SUVmax) ≤ 6.5, localized disease, normal levels of serum soluble interleukin-2 receptor, and the number of involved nodal sites ≤ 3 immediately prior to 90Y-IT were associated with median PFS greater than 6 years. However, in multivariate analysis, only tumor long-axis diameter ≤ 2.5 cm and SUVmax ≤ 6.5 affected PFS [hazard ratio (HR) 0.130, P = 0.0021 and HR 0.283, P = 0.0311, respectively]. Patients with only one prior regimen needed less granulocyte colony-stimulating factor and platelet transfusion. Thus, 90Y-IT treatment should be considered for patients with indolent lymphoma in first relapse who have tumor long-axis diameter ≤ 2.5 cm and SUVmax ≤ 6.5.

MECHANISMS IN ENDOCRINOLOGY: Hypophysitis: diagnosis and treatment

Hypophysitis is a rare condition characterised by inflammation of the pituitary gland, usually resulting in hypopituitarism and pituitary enlargement. Pituitary inflammation can occur as a primary hypophysitis (most commonly lymphocytic, granulomatous or xanthomatous disease) or as secondary hypophysitis (as a result of systemic diseases, immunotherapy or alternative sella-based pathologies). Hypophysitis can be classified using anatomical, histopathological and aetiological criteria. Non-invasive diagnosis of hypophysitis remains elusive, and the use of currently available serum anti-pituitary antibodies are limited by low sensitivity and specificity. Newer serum markers such as anti-rabphilin 3A are yet to show consistent diagnostic value and are not yet commercially available. Traditionally considered a very rare condition, the recent recognition of IgG4-related disease and hypophysitis as a consequence of use of immune modulatory therapy has resulted in increased understanding of the pathophysiology of hypophysitis. Modern imaging techniques, histological classification and immune profiling are improving the accuracy of the diagnosis of the patient with hypophysitis. The objective of this review is to bring readers up-to-date with current understanding of conditions presenting as hypophysitis, focussing on recent advances and areas for future development. We describe the presenting features, investigation and diagnostic approach of the patient with likely hypophysitis, including existing conventional techniques and those in the research/development arena. Hypophysitis usually results in acute and persistent pituitary hormone deficiency requiring long-term replacement. Management of hypophysitis includes control of the inflammatory pituitary mass using a variety of treatment strategies including surgery and medical therapy. Glucocorticoids remain the mainstay of medical treatment but other immunosuppressive agents (e.g. azathioprine, rituximab) show benefit in some cases, but there is a need for controlled studies to inform practice.

IgG4-related Lung Pseudotumor and Pleural Inflammation with Autoimmune Hepatitis

A 63-year-old man was admitted to our department following a secondary medical examination. Blood tests showed high levels of liver enzymes, IgG, IgG4, and antinuclear antibody. Computed tomography showed tumors in the bilateral lower lobes of the lungs and pleural thickening. After pleural and liver biopsy procedures, he was conclusively diagnosed with IgG4-related lung pseudotumor and pleural inflammation with autoimmune hepatitis. We started treatment with prednisolone 40 mg/day, and chest radiograph and blood tests showed signs of improvement. This was a rare case that suggested an association between IgG4-related disease and autoimmune hepatitis.

IgG4-Related Kidney Disease in a Patient With History of Breast Cancer: Findings on 18F-FDG PET/CT

A 64-year-old African American woman with history of stage III breast carcinoma, 3 years after complete response to therapy, presents with progressive fatigue, increasing arthralgia, and unintentional weight loss of 15 lb in 3 months. An F-FDG PET demonstrated new diffuse FDG avidity of the renal parenchyma, new FDG-avid foci in pancreas and lungs, and new FDG-avid lymph nodes above and below the diaphragm. While a retroperitoneal lymph node biopsy was inconclusive, a kidney biopsy resulted in diagnosis of diffuse, severe, IgG4-related tubulointerstitial nephritis. Treatment with corticosteroid led to complete resolution of the symptoms and PET findings.

Introduction of nuclear medicine research in Japan

There were many interesting presentations of unique studies at the Annual Meeting of the Japanese Society of Nuclear Medicine, although there were fewer attendees from Europe than expected. These presentations included research on diseases that are more frequent in Japan and Asia than in Europe, synthesis of original radiopharmaceuticals, and development of imaging devices and methods with novel ideas especially by Japanese manufacturers. In this review, we introduce recent nuclear medicine research conducted in Japan in the five categories of Oncology, Neurology, Cardiology, Radiopharmaceuticals and Technology. It is our hope that this article will encourage the participation of researchers from all over the world, in particular from Europe, in scientific meetings on nuclear medicine held in Japan.

IgG4-related Disease with Bone Marrow Involvement

A 61-year-old Japanese woman with anemia, submandibular gland swelling, and enlarged lymph nodes was diagnosed with IgG4-related disease (IgG4-RD) by lymph node biopsy. Bone marrow involvement of IgG4-RD was detected by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and immunohistochemically proven by bone marrow biopsy in this patient. Anemia progressed gradually, and prednisolone treatment was initiated. Anemia and submandibular gland swelling improved soon after prednisolone treatment was initiated. We report a rare case of IgG4-RD involving the bone marrow. FDG-PET/CT and bone marrow biopsy were useful for diagnosis in this case.