Rheumatoid nodules: differential diagnosis and immunohistological findings

Rheumatoid pleurisy confirmed by biopsy of a chest wall nodule by thoracoscopy under local anaesthesia

Rheumatoid pleurisy is common in patients with rheumatoid arthritis, but distinguishing it from other diseases, such as heart failure and tuberculous pleurisy, is often difficult. A man in his 70s with stable rheumatoid arthritis presented with cardiac enlargement and bilateral pleural effusion on chest radiography. Pleural fluid studies showed lymphocytosis, adenosine deaminase level of 51.6 U/L and rheumatoid factor level of 2245.3 IU/mL, suggestive of rheumatoid pleurisy and tuberculous pleurisy. Thoracoscopy under local anaesthesia revealed erythema of the parietal pleura, small papillary projections and fibrin deposits. H&E-stained biopsy specimens showed inflammatory granulomas with strong lymphocytic infiltration and non-caseating granulomas. He was diagnosed with rheumatoid pleurisy. His symptoms improved with 30 mg of prednisolone. This study highlights that biopsy using thoracoscopy under local anaesthesia effectively diagnoses rheumatoid pleurisy, which may be challenging to diagnose.

Cutaneous Manifestations of Rheumatoid Arthritis: Diagnosis and Treatment

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder characterized by inflammatory arthritis and periarticular structural damage. Available evidence suggests that RA results from complex interactions between genetic susceptibility (e.g., HLA-DRB1), environmental factors (e.g., smoking), and immune dysregulation. Alongside joint-related symptoms, individuals with RA may also experience a wide array of skin issues, including the development of nodules, neutrophilic dermatoses, vasculitis, and vasculopathy. Treatment strategies for these manifestations vary but routinely involve corticosteroids, disease-modifying anti-rheumatic drugs, and biologics, with individualized approaches guided by disease severity. In this review, we provide comprehensive insights into the skin-related issues associated with RA, outlining their clinical characteristics and histopathological findings. Our aim is to facilitate early diagnosis and personalized treatment to improve the quality of life of affected individuals.

Rheumatoid nodule presenting as an indeterminate soft tissue mass in the sole of the foot

A 64-year-old lady with a background of rheumatoid arthritis presented to the foot and ankle clinic with lump underneath the sole of her foot causing significant discomfort. Examination revealed she had a swelling of the first and the second metatarsophalangeal joints. Magnetic resonance imaging revealed abnormal soft tissue thickening between the second and the third metatarsal and a single large encapsulating indeterminate soft tissue mass with a peripheral inflammatory rim. The appearance was suggestive of a malignant sarcoma rather than a rheumatoid nodule or rheumatoid tenosynovitis. The patient was referred to the regional sarcoma unit where the scans were reviewed, and a sarcoma was ruled out. The patient then underwent excision of the indeterminate soft tissue mass. Histology revealed granulomatous infiltration suggestive of a rheumatoid nodule. This has not been described previously in the literature.

Rheumatoid nodules: a narrative review of histopathological progression and diagnostic consideration

Rheumatoid nodules (RNs) are the most common extra-articular manifestation of rheumatoid arthritis and are also seen in patients with other autoimmune and inflammatory diseases. The development of RNs includes histopathological stages of acute unspecified inflammation, granulomatous inflammation with no or minimal necrosis, necrobiotic granulomas typically with central fibrinoid necrosis surrounded by palisading epithelioid macrophages and other cells, and likely an advanced stage of "ghost" lesions containing cystic or calcifying/calcified areas. In this article, we review RN pathogenesis, histopathological features in different stages, diagnostically related clinical manifestations, as well as diagnosis and differential diagnosis of RNs with an in-depth discussion about challenges in distinguishing RNs from their mimics. While the pathogenesis of RN formation remains elusive, it is hypothesized that some RNs with dystrophic calcification may be in transition and may be in coexistence or collision with another lesion in patients with RA or other soft tissue diseases and comorbidities. The diagnosis of typical or mature RNs in usual locations can be readily made by clinical findings often with classic RN histopathology, but in many cases, particularly with atypical or immature RNs and/or unusual locations, the clinical and histopathological diagnosis can be challenging requiring extensive examination of the lesional tissue with histological and immunohistochemical markers to identify unusual RNs in the clinical context or other lesions that may be coexisting with classic RNs. Proper diagnosis of RNs is critical for appropriate treatment of patients with RA or other autoimmune and inflammatory diseases.

Bilateral epibulbar pseudorheumatoid nodulosis with a review of ocular adnexal palisading granulomas

We describe the clinical, histopathologic, and immunohistochemical characteristics of episcleral/conjunctival pseudorheumatoid nodulosis, a new granulomatous entity that belongs among a group of related lesions. Specifically, pseudorheumatoid nodulosis should be differentiated from solitary rheumatoid nodules, rheumatoid nodulosis, accelerated rheumatoid nodules and nodulosis, and solitary pseudorheumatoid nodules. A 53-year-old man presented with bilateral painless, large, faintly yellow-gray, partially immobile, solid, circumscribed, and occasionally confluent episcleral nodules of several months' duration. He had never had clinical rheumatoid arthritis and was rheumatoid factor negative. Biopsy revealed multiple, merging episcleral/conjunctival, nonulcerated, palisading granulomas with variably sized central zones of necrobiosis of collagen. Abundant palisading CD68/163 + histiocytes admixed with fibroblasts surrounded the necrobiotic foci, which failed to stain with Alcian blue for mucopolysaccharides. No fibrinoid deposits were detected. Numerous CD3+ T lymphocytes, fewer CD 20 + B lymphocytes, and a smaller subpopulation of CD138 + plasma cells were present. Numerous CD1a + Langerhans cells were scattered among the palisading histiocytes and overlying epithelium. Immunohistochemical stains for immunoglobulins revealed concentrations of IgG, IgM, and IgA, but not IgE, in the necrobiotic zones. Special stains did not reveal evidence of infection nor did polarization microscopy display any foreign material. An extensive systemic and serologic workup was negative. We review simulating palisading or other nonrheumatic granulomas that should be distinguished from pseudorheumatoid nodules or nodulosis and explore therapeutic options.

[Differential diagnosis of granulomatous diseases]

Despite advances in the understanding of the pathophysiology, granulomatous diseases remain a diagnostic challenge for the clinician as well as for the pathologist. However, establishing the correct diagnosis of these diseases is a crucial prerequisite of targeted therapy. It is particularly essential to distinguish between an infectious and a non-infectious cause, since anti-infectious and anti-inflammatory or immunosuppressive approaches are opposing. Failure to establish the correct diagnosis can lead to adverse consequences for the patient. An interdisciplinary approach and a critical assessment of clinical, laboratory-chemical, microbiological, imaging, and anatomical-pathological findings are crucial for the evaluation of granulomatous disorders. This overview summarizes important landmarks and their value in the interplay of arriving at the correct diagnosis.

Multiple Asymptomatic Juxta-Articular Nodules Mimicking Tuberous-Xanthoma-A Unusual Presentation of Tophaceous Gout

Asymptomatic, juxta-articular nodules are an uncommon morphology, which is usually diagnosed as xanthomas, calcinosis cutis or rheumatoid nodules. This study was represented as a case of gout, which is a disorder of purine metabolism resulting in elevation of serum uric acid and deposition of monosodium urate crystals within and around joints and manifests clinically as inflammatory arthritis. Urate crystal deposits have also been found in tendons, ligaments, viscera, and the skin, with the term “tophi” being used for the non-articular deposits. In the chronic stage, the lesion can be asymptomatic lesions and is often misdiagnosed.

An Unusual Cause of Refractive Chronic Bilateral Leg Ulceration

Background:

Ulceration of the lower extremities is a common disorder that can be very painful. It occurs most frequently in the elderly population as a result of venous hypertension. We report an unusual case of a 32-year-old man with an 11-year history of extensive, painful, bilateral leg ulcers resistant to conventional treatment necessitating above-knee amputation of the left leg. Eventually, the patient was treated with prednisone, which led to almost complete healing of the ulcers of the right leg.

Objective:

The objective of this report is to discuss a rare cause of chronic bilateral leg ulceration.

Methods:

Detailed histopathologic examination showed a complex pattern of overlapping features of several specific dermatologic conditions, including necrobiosis lipoidica (NL), necrobiotic xanthogranuloma (NXG), and the destructive form of granuloma annulare (GA).

Conclusion:

The characteristics of our patient suggest a variant of a cutaneous necrobiotic disorder that has not been previously reported. When clinicians are confronted with recalcitrant ulcerations in the lower extremity, this group of disorders should be considered in the differential diagnosis.

Histologic features of granulomatous skin diseases. Part 1: Non-infectious granulomatous disorders

Granulomatous disorders affecting the skin belong to a heterogeneous group of diseases. With the exception of granulomas induced by infectious agents or foreign bodies, the etiopathogenesis of granulomatous disorders is still poorly understood. The knowledge of histopathologic changes is of great importance for understanding clinical presentation and disease course.

Soft tissue swellings in the foot: rheumatoid nodulosis

Background rheumatoid nodulosis is a rare disease characterised by multiple subcutaneous nodules, a high titre of rheumatoid factor, radiologically detectable cystic bone lesions, but with none or few of the systemic manifestations or joint activity of rheumatoid disease. Histopathologically, nodulosis is the same as the nodules found in rheumatoid arthritis. It is considered to be a benign variant of rheumatoid arthritis. A 69 year old male presents with multiple subcutaneous nodules on the feet. This case study highlights the benefits of ultrasound in establishing a correct diagnosis and management. Although rare, rheumatoid nodulosis is a consideration in the differential diagnoses of soft tissue swellings in the feet.

[The rheumatoid hand]

Rheumatoid arthritis usually affects the hand (90%). Without treatment, joint damages and deformities lead to loss of the ability to grip, grasp, and pinch, often leaving the patient unable to perform the activities of daily living. Early treatment with DMARDs ± physical therapy is the best way to control the disease and prevent deformity, as well as disability, which often occurs when joints get damaged. Two decades later dramatic advances have been made in the medical therapy of RA with the expanded range of effective disease-modifying antirheumatic drugs. When a patient with RA develops joint damages in the hand or wrist that are unresponsive to medical management and injections therapy, surgical intervention may be necessary. Optimal care involves a team approach among the patient involving rheumatologists, physical therapists and hand surgeons. Patients with RA should be closely monitored in order to detect joint damages necessitating physical therapist or hand surgeon consultation.

Cutaneous nodules in patients with rheumatoid arthritis: a case report and review of literatures

We report a case of 57-year-old Japanese woman with an overlap syndrome of both rheumatoid arthritis (RA) and autoimmune hepatitis, who developed multiple skin nodules. An extensive biopsies of the nodules revealed rheumatoid neutrophilic dermatitis, showing panniculitis without vasculitis, combining with granulomatous formation histopathologically. Since cutaneous nodules in patients with RA are very complex, differential diagnosis should be done according to disease activities, medications used, and pathological findings. We suggest that the differences in histopathological findings of cutaneous nodules in patients with RA depend on their immunological conditions based on disease activities including therapeutic effects.

Mycobacterium-associated lobular panniculitis, mimicking a rheumatoid nodule in a patient with rheumatoid arthritis

Mycobacterium-associated lobular panniculitis can mimic a rheumatoid nodule and has been seldom reported in rheumatoid arthritis (RA). We describe a 69-year-old woman with RA who presented initially with fever and an indurated skin lesion on the right thigh. Lobular panniculitis was diagnosed after biopsy and was then treated with prednisolone. After this therapy, pulmonary infiltration developed and was later shown by transbronchial biopsy to be caused by Mycobacterium tuberculosis. The panniculitis skin lesion became smaller after prednisolone therapy and was further improved after antituberculosis drugs were added. Reexamination of the previously biopsied skin tissue disclosed acid-fast bacilli. Reactivation or new infection of M. tuberculosis is a current important issue in RA patients, especially after treatment with disease-modifying anti rheumatic drugs or antitumor necrosis factor agents. Mycobacterium-associated lobular panniculitis should be included in the differential diagnosis of indurated skin disorder in RA patients, and acid-fast staining or polymerase chain reaction examination of tuberculosis should be performed routinely on biopsied skin tissue.

Palisading granuloma presenting in a patient with systemic lupus erythematosus

A patient with systemic lupus erythematosus who developed a distinctive nodular eruption demonstrating typical features of palisading granuloma is presented herein. A 60-year-old woman was admitted complaining of an elastic-hard, indurated nodule on the right dorsal aspect of the metacarpophalangeal joint of her third finger with a history of several years. She was successfully treated for her lupus nephritis with oral predonisolone. She had experienced erythema on her cheeks after sun exposure and polyarthralgia for a decade. Laboratory examination revealed positive results for antinuclear antibody and rheumatoid factor. Peripheral blood cell counts showed leukocytopenia and lymphocytopenia. Results of hand X-ray were unremarkable. Histological examination of the skin biopsy specimen from the nodule revealed a structure composed of a central area of fibrinoid necrosis, surrounded by a middle zone of palisading cells and an outer zone of chronic lymphocyte infiltrate. These findings led us to the histological diagnosis of palisading granuloma. She was diagnosed as having systemic lupus erythematosus complicated with a rheumatoid nodule. She is currently under treatment with cyclophosphamide (50 mg/day) without exaggeration of her systemic lupus erythematosus and nodule.

Sudden Cardiac Death due to Giant Cell Inflammatory Processes

Granulomatous inflammation of the myocardium may occur in a number of systemic disease processes including those with infectious etiologies such as fungal, mycobacterial and parasitic infections, as well as hypersensitivity reactions, and rarely autoimmune disorders. In many of these disorders, giant cells are components of the inflammatory infiltrate. Systemic granulomatous processes of unknown pathogenesis, most notably sarcoidosis, may also be associated with involvement of the myocardium. Occasionally, these disorders are associated with sudden death due to pathologic involvement of the heart. In contrast, giant cell myocarditis, also known as idiopathic myocarditis, a rare, frequently fulminant and fatal disorder of unknown etiology, is isolated to the heart and lacks systemic involvement. This disorder is most commonly diagnosed at autopsy. We present two cases in which sudden death resulted from a giant cell inflammatory process affecting the myocardium. Both individuals lacked antemortem diagnoses and collapsed at their respective places of employment. These cases compare and contrast the clinical and pathologic issues involved in the differential diagnoses of the subgroup of sudden cardiac deaths resulting from giant cell inflammatory processes that affect the myocardium, as well as the value of histologic examination and immunohistochemical studies.

Rheumatoid Nodule

Rheumatoid nodules are the most common extra-articular manifestation of rheumatoid arthritis. Dermatologist may be concerned with the diagnosis and management of rheumatoid nodules, although most patients will probably be under the care of a rheumatologist. This article focuses in clinical, pathogenic, diagnostic, and therapeutic aspects of rheumatoid nodules. Classic rheumatoid nodules commonly occur in genetically predisposed patients with severe, seropositive arthritis. However, they may appear in other clinical settings. Accelerated rheumatoid nodulosis, especially involving the hands, has been reported in patients receiving methotrexate, antitumor necrosis factor alpha biologic drugs or leflunomide therapy for rheumatoid arthritis. Rheumatoid nodulosis is characterized by multiple rheumatoid nodules, recurrent joint symptoms with minimal clinical or radiologic involvement, and a benign clinical course. Pseudorheumatoid nodules have been reported in healthy children. Although histologically almost indistinguishable from true rheumatoid nodules, some consider these lesions to be a form of deep granuloma annulare.

What is That Nodule?

The evaluation of patients with subcutaneous nodules remains a diagnostic challenge. The presence of nodules can be a clue to an underlying systemic disease; however, the varied presentations of nodules and numerous disease associations make the assessment of patients with nodules far from simple. With further investigation into the appearance, location, and symptoms associated with nodules, the clinical significance of these lesions can become clearer and aid in logical diagnostic evaluation. We have reviewed the causes of nodules with emphasis on those associated with rheumatic disease and provide guidelines for nodule evaluation to better characterize disease association and lead to directed diagnostic assessment.

Rheumatoid nodulosis. Two cases with destructive polyarthritis after 20 years

The term "rheumatoid nodulosis" was coined by Ginsberg in 1975 to designate a rare and distinctive form of rheumatoid disease. Anecdotal case reports suggest a benign nondestructive course, although prolonged follow-up data are usually unavailable. We describe two cases of typical rheumatoid nodulosis with follow-ups exceeding 25 years. Onset occurred at 14 and 22 years of age, respectively. Both patients presented with palindromic rheumatism, positive tests for rheumatoid factors, negative tests for other biological markers, and normal radiographs. Multiple subcutaneous nodules developed after 4 and 6 years with palindromic flares, respectively. Functional impairments and disfigurement required several surgical procedures to remove nodules. Histology was typical for rheumatoid nodules. Neither patient responded to disease-modifying anti-rheumatic drugs (gold, antimalarials, and D-penicillamine). Treatment consisted of nonsteroidal anti-inflammatory drugs combined with prednisone as needed. After 20 and 22 years of follow-up, respectively, both patients had typical rheumatoid arthritis with deformities and radiological joint destruction. In conclusion, these two cases establish that rheumatoid nodulosis can occur as a presentation of rheumatoid arthritis with a potential for severe joint damage after many years.

MRI appearance of retrocalcaneal bursitis and rheumatoid nodule in a patient with rheumatoid arthritis

Rheumatoid arthritis is an autoimmune disorder of unknown etiology characterized by symmetric, erosive synovitis and sometimes multisystem involvement. Rheumatoid nodules have been reported in as many as 20-30% of patients with rheumatoid arthritis; however, they are not commonly seen in the feet. We present magnetic resonance (MR) findings of a rarely seen case of rheumatoid bursitis in the retrocalcaneal bursa associated with a subcutaneous rheumatoid nodule inferior to the calcaneus which histologically confirmed the rheumatoid arthritis. To the best of our knowledge, this is the first case that rheumatoid bursitis in the retrocalcaneal bursa associated with the rheumatoid nodule in the foot was revealed by MR imaging.

An unusual cause of refractive chronic bilateral leg ulceration

BACKGROUND

Ulceration of the lower extremities is a common disorder that can be very painful. It occurs most frequently in the elderly population as a result of venous hypertension. We report an unusual case of a 32-year-old man with an 11-year history of extensive, painful, bilateral leg ulcers resistant to conventional treatment necessitating above-knee amputation of the left leg. Eventually, the patient was treated with prednisone, which led to almost complete healing of the ulcers of the right leg.

OBJECTIVE

The objective of this report is to discuss a rare cause of chronic bilateral leg ulceration.

METHODS

Detailed histopathologic examination showed a complex pattern of overlapping features of several specific dermatologic conditions, including necrobiosis lipoidica (NL), necrobiotic xanthogranuloma (NXG), and the destructive form of granuloma annulare (GA).

CONCLUSION

The characteristics of our patient suggest a variant of a cutaneous necrobiotic disorder that has not been previously reported. When clinicians are confronted with recalcitrant ulcerations in the lower extremity, this group of disorders should be considered in the differential diagnosis.

Tumour necrosis factor alpha independent disease mechanisms in rheumatoid arthritis: a histopathological study on the effect of infliximab on rheumatoid nodules

BACKGROUND

It has been suggested that the immunopathology of rheumatoid nodules parallels that of inflamed synovium in rheumatoid arthritis (RA).

OBJECTIVE

To analyse the effect of infliximab on the immunopathology of rheumatoid nodules in order to provide new insights into the relationship between synovial inflammation and rheumatoid nodules.

MATERIALS AND METHODS

Nodules were present at baseline in six patients with RA and after infliximab treatment in five patients, including paired nodules before and after treatment in three patients. In one patient, the nodule appeared during treatment. Paraffin sections were used for histological analysis. Frozen sections were stained by immunohistochemistry for cellular markers (CD3, CD4, CD8, CD16, CD20, CD68), blood vessels (CD146, vWF, alphavbeta3), and adhesion molecules (E-selectin, VCAM-1, ICAM-1).

RESULTS

No manifest immunopathological differences were found between the nodules before and after infliximab treatment. All nodules depicted the classical structure with a central necrotic zone, surrounding the palisade layer, and an outer connective tissue zone. Immunohistochemistry showed the presence of CD68+ and CD16+ macrophages in the palisade and the connective tissue zone, as well as a small number of CD3+, CD4+ T lymphocytes in the perivascular areas. Small vessels were seen in the connective tissue and were sometimes positive for the neovascularisation marker alphavbeta3. They expressed no VCAM-1, E-selectin weakly, but ICAM-1 strongly. ICAM-1 was also strongly expressed on palisade cells.

CONCLUSIONS

Despite an improvement of articular symptoms, infliximab treatment had no distinct effect on the histopathology of rheumatoid nodules, suggesting that different pathogenetic mechanisms mediate the two disease manifestations in RA.

A giant rheumatoid nodule

Subcutaneous rheumatoid nodules occur commonly in advanced cases of rheumatoid arthritis and are the most common extra-articular lesion of this disease. We present a case of a very unusual giant rheumatoid nodule that developed on the lateral side of a knee. The case was devoid of systemic symptoms of arthritis and the lesion was limited to a rheumatoid nodule. The nodule was successfully treated by surgical excision. However, other new nodules developed in her hand. Her clinical course has not been satisfactory.

Incidence of rheumatoid nodule in Dalmatia: similarities and differences among populations

BACKGROUND

The specific aim of our study was neither prognosis nor long-term evaluation but focus on determining incidence of rheumatoid nodules (RN) in a large population of patients with rheumatoid arthritis (RA) on the coastline of Croatia (Dalmatia) within a certain range. We compared our data with those published previously in the literature.

METHODS

Our study was focused on determining incidence of RN occurrence in patients with rheumatoid arthritis in Dalmatia, Croatia by comparing these figures with data reported elsewhere and evaluating its importance in the process of diagnosing RA. The duration of the study was 10 years (1991-2001). There were 421 patients (344 women and 77 men) with confirmed RA diagnosis. Median follow-up time was 2 years (range: 1.4-3.5 years).

RESULTS

Existence of RN was established by clinical examination in 109 of 421 patients; incidence density was 17.3%. RN occurred somewhat more frequently in men (32%) as compared to women (24%) without statistically significant difference. In 38% of patients, RN occurred simultaneously in several sites, more frequently in men (64%) than in women (30%) (odds ratio [OR] 2.13, p <0.05). Correlation of seropositivity and RN appearance was very high: positive in 84% of patients with nodules as compared to 58% of patients without nodules (OR 1.45, p <0.05) with no statistically significant differences between sexes.

CONCLUSIONS

Results obtained warrant the conclusion that RN incidence in our patients from Dalmatia is comparable with results of earlier Croatian studies as well as with Western European figures and Caucasian population data reported on other continents. RN incidence differs significantly for Asian and Arabian populations, i.e., is less frequent, and for the U.S. population, where it is more frequent.

Panniculitis. Part I. Mostly septal panniculitis

The panniculitides represent a group of heterogeneous inflammatory diseases that involve the subcutaneous fat. The specific diagnosis of these diseases requires histopathologic study because different panniculitides usually show the same clinical appearance, which consists of subcutaneous erythematous nodules on the lower extremities. However, the histopathologic study of panniculitis is difficult because of an inadequate clinicopathologic correlation, and the changing evolutionary nature of the lesions means that biopsy specimens are often taken from late-stage lesions, which results in nonspecific histopathologic findings. In addition, large-scalpel incisional biopsies are required. However, we believe that by obtaining appropriate biopsy specimens and with adequate clinicopathologic correlation, a specific diagnosis may be rendered in most cases of panniculitis. It must be accepted that all panniculitides are somewhat mixed because the inflammatory infiltrate involves both the septa and lobules; however, in general the differential diagnosis between a mostly septal and a mostly lobular panniculitis is straightforward at scanning magnification. Mostly septal panniculitides with vasculitis include leukocytoclastic vasculitis involving the small blood vessels of the septa; superficial thrombophlebitis resulting from inflammation and subsequent thrombosis of large veins of the septa; and cutaneous polyarteritis nodosa, which is a vasculitis involving arteries and arterioles of the septa of subcutaneous fat with few or no systemic manifestations. Often septal panniculitides with no vasculitis are the consequence of dermal inflammatory processes extending to the subcutaneous fat, such as necrobiosis lipoidica, scleroderma, subcutaneous granuloma annulare, rheumatoid nodule, and necrobiotic xanthogranuloma. However, in other cases, the inflammatory process is primarily located in the fibrous septa of the subcutis with or without involvement of the overlying dermis. The most frequently seen septal panniculitis is erythema nodosum, which, in fully developed lesions, is characterized histopathologically by Miescher's radial granulomas in the septa.

A comparative phenotypical analysis of rheumatoid nodules and rheumatoid synovium with special reference to adhesion molecules and activation markers

OBJECTIVES

(1) To analyse the in situ expression of adhesion molecules in rheumatoid nodules. (2) To compare the endothelial expression of adhesion molecules in synovial tissue and subcutaneous nodules obtained from the same patients. (3) To compare the expression of adhesion molecules and activation markers on T cell lines from nodules and synovium.

METHODS

(1) Immunohistochemical analysis by APAAP technique of E selectin, CD44, ICAM-1, PECAM-1, and VCAM-1 was performed on 10 rheumatoid nodules from seven patients with rheumatoid arthritis (RA); nodules and synovium were simultaneously analysed from three patients. (2) T cell lines were generated from RA nodules (n = 7) and synovium (n = 7) by interleukin 2 expansion, and subsequently characterised by flow cytometry for surface expression of alpha E beta 7, alpha 4 beta 7, CD44, L selectin, LFA-1a, PECAM-1, and CD30.

RESULTS

(1) In rheumatoid nodules, the palisading layer strongly stains for ICAM-1 and PECAM-1, but less pronounced for CD44. VCAM-1 staining was usually negative. ICAM-1 is upregulated in the vessels surrounding the central zone of fibrinoid necrosis. The immunohistological picture in different nodules derived from the same patient was similar. (2) The endothelial expression of adhesion molecules is comparable in RA nodules and synovium on an individual level, except for E selectin, which is overexpressed in nodule endothelium. (3) T cell lines from nodules and synovium display similar adhesion molecule profiles. However, the expression of CD30, a T cell activation marker linked with Th2 subsets, is higher in nodules compared with synovium.

CONCLUSION

These data support a recirculation hypothesis of T cells between articular and extra-articular manifestations in RA, although the activation state of the T cells in each of these localisations may differ.

Deep granuloma annulare (pseudorheumatoid nodule) in children: clinicopathologic study of 35 cases

Deep granuloma annulare (DGA) is one of several lesions of skin and superficial soft tissues whose histologic character is a palisading granuloma with a small central focus of necrosis or necrobiosis. Unlike the other palisading necrobiotic lesions, DGA has a predilection for children in the first 5 to 6 years of life. A painless subcutaneous nodule(s) in the lower anterior tibial region or foot and the scalp, typically in the occiput, was the most common presenting feature in this study of 35 cases. Additional or recurrent lesions were reported in approximately 70% of cases with clinical follow-up. All lesions showed the presence of necrobiosis; however, one of the characteristic features was the multinodular character of the predominantly mononuclear cellular aggregates. The presence of vascular spaces at the periphery of the nodular profiles served as a clue to the diagnosis of DGA. The palisading arrangement of the mononuclear cells was evident only in those foci with central necrobiosis. A histiocytic disorder or fibrohistiocytic process was a common consideration in the differential diagnosis, especially in those cases with less apparent foci of necrosis. Palisading histiocytes with prominent eosinophilic cytoplasm and some nuclear atypism were problematic with regard to possible epithelioid sarcoma. Our study failed to identify any underlying or predisposing factors in the development of DGA. Despite the fact that DGA is a well-documented lesion in children, it occurs sufficiently infrequently that it is often not considered clinically when it presents as a subcutaneous mass or masses in a child. Its recognition by the pathologist is especially important as the occurrence of additional lesions in a high proportion of children can be anticipated without undue concern.

Rheumatoid nodules: MR/pathological correlation

PURPOSE

To demonstrate the signal characteristics of subcutaneous rheumatoid nodules in correlation to their histopathologic features.

METHOD

The magnetic resonance imaging (MRI) features of biopsy proven subcutaneous rheumatoid nodules are described in five patients with rheumatoid arthritis established by classic criteria.

RESULTS

Two morphologic appearances of rheumatoid nodules were observed on MRI: one predominantly cystic, with enhancing peripheral component; and a second type which is predominantly solid, with uniform enhancement following gadolinium injection.

CONCLUSION

Subcutaneous rheumatoid nodules can appear by MR as solid, cystic, or a combination of both components. This closely correlates with their histopathologic evolution.

Methotrexate-associated appearance and rapid progression of rheumatoid nodules in systemic-onset juvenile rheumatoid arthritis

Rheumatoid nodules are a rare extraarticular manifestation of juvenile rheumatoid arthritis (JRA), usually detected in patients with polyarticular-onset disease and positive rheumatoid factor (RF). To date, there has not been a published report of rheumatoid nodules in systemic-onset JRA. Low-dose methotrexate (MTX) is generally considered to be the most useful second-line drug in the treatment of polyarticular JRA. In adult RA, MTX has been shown to be associated with appearance and progression of rheumatoid nodules. This report describes a 3-year-old girl with RF-negative, antinuclear antibody-negative systemic JRA who developed multiple rheumatoid nodules on the scalp and trunk during MTX therapy. The first nodule developed on the scalp 6 months after MTX treatment was initiated. Previous treatment with azathioprine was not associated with nodulosis. This represents an atypical case of MTX-associated accelerated nodulosis in systemic JRA, and raises the problem of treatment plan modification in the presence of this side effect.

Plasma viscosity in giant cell arteritis

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