Clonally expanded CD38 cytotoxic CD8 T cells define the T cell infiltrate in checkpoint inhibitor-associated arthritis.

Immune checkpoint inhibitor (ICI) therapies used to treat cancer, such as anti-PD-1 antibodies, can induce autoimmune conditions in some individuals. The T cell mechanisms mediating such iatrogenic autoimmunity and their overlap with spontaneous autoimmune diseases remain unclear. Here, we compared T cells from the joints of 20 patients with an inflammatory arthritis induced by ICI therapy (ICI-arthritis) with two archetypal autoimmune arthritides, rheumatoid arthritis (RA) and psoriatic arthritis (PsA).

Drivers of heterogeneity in synovial fibroblasts in rheumatoid arthritis.

Inflammation of non-barrier immunologically quiescent tissues is associated with a massive influx of blood-borne innate and adaptive immune cells. Cues from the latter are likely to alter and expand activated states of the resident cells. However, local communications between immigrant and resident cell types in human inflammatory disease remain poorly understood.

Rosai-Dorfman Disease of Bone and Soft Tissue.

Context.—: Rosai-Dorfman disease is a rare histiocytic proliferative disorder of unknown pathogenesis that may be diagnostically difficult in extranodal sites. It is commonly an unsuspected diagnosis when arising in bone and soft tissue, especially when it presents without associated lymphadenopathy.

Subarticular Inflammatory Pseudoabscesses: A Pathologic Study With Clinical Correlation.

Abnormal accumulation of neutrophils in a subarticular bone usually raises the concern for osteomyelitis or septic arthritis, a disabling and potentially life-threatening medical condition. At the pathology department of a specialized orthopedic institute, we observed a distinct pattern of subarticular inflammation mimicking infection characterized by collections of neutrophils, macrophages, and fibrin in pseudocystic spaces of variable size and extent in the superficial subarticular bone not accompanied by granulation tissue or necrosis. We coined the term "inflammatory pseudoabscess" to describe these accumulations.

Rheumatoid Arthritis Morning Stiffness Is Associated With Synovial Fibrin and Neutrophils.

Objective: Morning stiffness is a hallmark symptom of rheumatoid arthritis (RA), but its etiology is poorly understood. This study was undertaken to determine whether any histologic features of synovium are associated with this symptom.

Methods: Data on patient-reported morning stiffness duration and severity, and Disease Activity Score in 28 joints (DAS28) were collected from 176 patients with RA undergoing arthroplasty.

Rheumatoid Arthritis Flares After Total Hip and Total Knee Arthroplasty: Outcomes at One Year.

Objective: Most patients with rheumatoid arthritis (RA) undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) have active RA and report postoperative flares; whether RA disease activity or flares increase the risk of worse pain and function scores 1 year later is unknown.

Methods: Patients with RA were enrolled before THA/TKA. Patient-reported outcomes, including the Hip disability and Osteoarthritis Outcome Score (HOOS)/Knee Injury and Osteoarthritis Outcome Score (KOOS) and physician assessments of disease characteristics and activity (Disease Activity Score in 28 joints [DAS28] and Clinical Disease Activity Index), were collected before surgery.

Lytic Lesion in the Proximal Humerus After a Flu Shot: A Case Report.

Case: There has been a recent campaign to vaccinate patients in an effort to prevent widespread flu pandemic. Although the complication rate after vaccine is low, there have been reports of Guillain-Barré syndrome and shoulder injury related to vaccine administration (SIRVA). In this case presentation, we discuss a patient who developed a large lytic lesion in the proximal humerus after a deeply administered flu shot.

HBEGF macrophages in rheumatoid arthritis induce fibroblast invasiveness.

Macrophages tailor their function according to the signals found in tissue microenvironments, assuming a wide spectrum of phenotypes. A detailed understanding of macrophage phenotypes in human tissues is limited. Using single-cell RNA sequencing, we defined distinct macrophage subsets in the joints of patients with the autoimmune disease rheumatoid arthritis (RA), which affects ~1% of the population.

Histologic and Transcriptional Evidence of Subclinical Synovial Inflammation in Patients With Rheumatoid Arthritis in Clinical Remission.

Objective: Patients with rheumatoid arthritis (RA) in clinical remission may have subclinical synovial inflammation. This study was undertaken to determine the proportion of patients with RA in remission or with low disease activity at the time of arthroplasty who had histologic or transcriptional evidence of synovitis, and to identify clinical features that distinguished patients as having subclinical synovitis.

Methods: We compared Disease Activity Score in 28 joints (DAS28) to synovial histologic features in 135 patients with RA undergoing arthroplasty.

Identification of Three Rheumatoid Arthritis Disease Subtypes by Machine Learning Integration of Synovial Histologic Features and RNA Sequencing Data.

Objective: In this study, we sought to refine histologic scoring of rheumatoid arthritis (RA) synovial tissue by training with gene expression data and machine learning.

Methods: Twenty histologic features were assessed in 129 synovial tissue samples (n = 123 RA patients and n = 6 osteoarthritis [OA] patients). Consensus clustering was performed on gene expression data from a subset of 45 synovial samples.

Success of scaphoid nonunion surgery is independent of proximal pole vascularity.

Unlabelled: We followed 35 consecutive patients with scaphoid nonunions in a prospective longitudinal registry. All nonunions were treated with curettage, non-vascularized autogenous grafting and headless screw fixation. Preoperative magnetic resonance imaging, intraoperative bleeding points and histopathological analysis of cancellous bone in the proximal pole were recorded as measures of viability.

Sonography of Morton Neuromas: What Are We Really Looking At?

Objectives: To determine what accounts for the sonographic appearance of a Morton neuroma by correlating preoperative sonograms with the sonographic appearance of the resected surgical specimen, the surgical findings, and the pathologic examination.

Methods: Ten Morton neuromas that had preoperative sonograms underwent postoperative specimen sonography and histologic evaluation. The appearance and size of the neuromas were compared between the preoperative and postoperative specimen images and were compared to the surgical and pathologic appearances.

The effect of myofibroblasts and corticosteroid injections in adhesive capsulitis.

Hypothesis: Adhesive capsulitis is a condition that results in restricted glenohumeral motion. Fibroblasts have been implicated in the disease process; however, their role as a contractile element in the development of fibrosis and capsular contracture is not well understood. We hypothesized (1) that myofibroblast prevalence in capsular biopsy specimens from patients with adhesive capsulitis would be increased compared with controls and (2) that patients treated with an intra-articular injection of corticosteroid would have fewer myofibroblasts.

Characteristics of glomus tumors in the hand not diagnosed on magnetic resonance imaging.

Purpose: To determine whether the diagnosis of hand glomus tumors by magnetic resonance imaging (MRI) is associated with tumor size, tumor pathology, tumor location, and/or clinical suspicion.

Methods: We reviewed our pathology database for patients with hand glomus tumors diagnosed between 2006 and 2013 and included those patients who had preoperative MRI at our institution. We excluded patients with recurrent and persistent tumors.

Recurrent pigmented villonodular synovitis and multifocal giant cell tumor of the tendon sheath: case report.

Intra- and extra-articular giant cell tumor of tendon sheath (GCTTS) and pigmented villonodular synovitis (PVNS) are histologically similar, usually benign tumors that can be characterized by synovial involvement (GCTTS) or overgrowth (PVNS). These tumors are most often found in the knee and digits of the hand. Although recurrence is a common feature of both conditions, multifocal lesions are rare.

The anatomy and histology of the bicipital tunnel of the shoulder.

Background: The bicipital tunnel is the extra-articular, fibro-osseous structure that encloses the long head of the biceps tendon.

Methods: Twelve cadaveric shoulder specimens underwent in situ casting of the bicipital tunnel with methyl methacrylate cement to demonstrate structural competence (n = 6) and en bloc harvest with gross and histologic evaluation (n = 6). The percentage of empty tunnel was calculated histologically by subtracting the proportion of cross-sectional area of the long head of the biceps tendon from that of the bicipital tunnel for each zone.

An atraumatic case of extensive Achilles tendon ossification.

Background: Ossification of the Achilles tendon is rare with most cases of ossification or calcification consisting of small, focal lesions. This pathology is usually predisposed by surgery, trauma, or other factors.

Case Description: A case of extensive Achilles ossification and calcification, without prior surgery or trauma, is reported.

Spontaneous intraneural hematoma of the sural nerve.

Symptomatic intraneural hemorrhage occurs rarely. It presents with pain and/or weakness in the distribution following the anatomic innervation pattern of the involved nerve. When a purely sensory nerve is affected, the symptoms can be subtle.

Comparison of clinical and histologic diagnoses in 16,587 total joint arthroplasties: implications for orthopedic and pathologic practices.

Objectives: To confirm how often histologic diagnoses correspond to reported clinical diagnoses in patients undergoing total joint arthroplasties.

Methods: We compared the submitting operative diagnosis with the pathologic diagnosis in 16,587 total joint arthroplasties for the seven most common diagnoses.

Results: The discrepancy rates between the submitted operative and histologic diagnosis were 18.

Diagnostic biopsy of the pronator teres and a motor branch of the median nerve: indications and technique.

Purpose: Biopsy of muscle tissue and motor nerve is helpful in the neurological evaluation of patients who present with upper limb and/or diffuse motor weakness. The procedure is indicated to supplement clinical, serological, and imaging diagnostic work-up of myopathic and neuropathic disorders. We describe a surgical technique and clinical series of biopsy of the pronator teres muscle and a motor branch of the median nerve.

Arthritis Pathology.

The pathologic examination of failed joints, whether natural or artificial, is an indispensable part of the understanding of arthritis, as it is the last, and still best opportunity to determine or verify the correct diagnosis. Accuracy in pathologic diagnosis, based on a firm understanding of the various disease processes, provides reliable data for use in clinical registries, provides an opportunity to explain the "unusual" clinical presentation, and ultimately gives the "best evidence" for basing further treatments and prognosis for the individual patient.

Fibrodysplasia ossificans progressiva: middle-age onset of heterotopic ossification from a unique missense mutation (c.974G>C, p.G325A) in ACVR1.

Fibrodysplasia ossificans progressiva (FOP) is the rare mendelian disease characterized by congenital malformation of the great toes preceding heterotopic ossification (HO) and caused by heterozygous activating mutation of the ACVR1 gene, which encodes the ALK2 receptor for bone morphogenetic proteins. Early adult life is the latest reported presentation for the HO of FOP. The patient of our report first developed HO from FOP at 47 years of age.

Cellular response to prosthetic wear debris differs in patients with and without rheumatoid arthritis.

Objective: To examine whether patients with rheumatoid arthritis (RA) demonstrate patterns of prosthetic wear or cellular responses to implant wear debris different from those demonstrated by patients without inflammatory joint disease.

Methods: Thirty-eight patients who had undergone a primary revision of a total elbow arthroplasty for aseptic loosening between 1996 and 2008 were identified. Twenty-five of these patients had RA, and 13 did not have inflammatory arthritis.