Rheumatoid nodules: MR/pathological correlation

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.

[Rheumatoid arthritis of the hand : Part 2: Imaging]

BACKGROUND

Rheumatoid arthritis can cause joint destruction, especially joints of the hands. Diagnosed at an early stage, which often includes imaging methods, can minimize structural joint damage and resulting disabilities as well as avoid systemic manifestations such as cardiovascular damage through rapid and continuous so-called targeted treatment approaches.

OBJECTIVE

The aim of this work is the systematic description and report of imaging findings in rheumatoid arthritis as the most common autoimmunologic rheumatologic disease, which is characterized by a typical pattern of synovitis of the hands.

MATERIALS AND METHODS

Narrative review based on the current literature on the subject from the radiological and rheumatological point of view.

RESULTS

Inflammation of the hands represents the most frequently affected area of the body in rheumatoid arthritis. Taking into consideration the topology and typical synovitis patterns of the hands, differences between early and late stages are described. Knowledge regarding image-based morphological changes associated with this complex disease, especially in the hands, is important in the differential diagnosis, especially in early stages of the disease.

CONCLUSIONS

For the diagnosis of rheumatoid arthritis of the hands, the radiologist must be familiar with basic knowledge of arthritis in the hands to confidently analyze the typical patterns present in the diagnostic imaging at initial diagnosis and during the course of the disease, which serve as a guide for therapy decisions.

Clinical Relevance and Immunohistochemical Patterns of Silent Pituitary Adenomas: 10 Years of Single-centre Experience

BACKGROUND

Silent pituitary adenomas are clinically non-functional (i.e., without clinically evident pituitary hormone production).

INTRODUCTION

The aim of this study was to investigate subjects with silent pituitary adenomas for possible variations in their clinical status.

METHODS

A total of 102 patients who had undergone surgery for pituitary adenoma and had been diagnosed with silent pituitary adenoma was included in the study. The patients' preoperative and postoperative hormonal parameters and magnetic resonance imaging (MRI) features were collected, and pathological specimens were re-evaluated.

RESULTS

Immunohistochemistry results of the 102 patients were as follows: hormone-negative adenomas (n=35) 35.5%; FSH+LH-positivity (n=32) 31.3%; ACTH-positivity (n=11) 10.7%; α-subunit- positivity (n= 9) 8.8%; prolactin-positivity (n=8) 7.8%; GH-positivity (n=6) 5.4%; and plurihormonal adenoma (n=1). The mean sizes of SGA, SGHA, and SCA were 28.0±12.7, 30.0±16.0, and 27.7±8.9mm (p>0.05), respectively. With the exception of silent gonadotroph adenomas (SGAs), female gender dominance was shown in patients with silent growth hormone adenoma (SGHA) and silent corticotroph adenoma (SCA). Although no clinical relevance was observed in relation to hormonal excess, preoperative GH (4.21±4.6, vs. 0.27±0.36 p=0.00) was slightly more elevated in SGHA than in GH-negative adenomas. Additionally, preoperative basal ACTH values (47.3±28.7 vs. 23.9±14.4, p=0.003) were also higher in SCA compared to the other types. Our findings revealed SCAs to be of more aggressive behaviour than SGHAs and SGAs due to invasiveness in radiological imaging, their elevated re-operation, and postoperative ACTH values.

CONCLUSION

Silent pituitary adenomas represent a challenging diagnostic tumour group. Careful initial evaluation of patients with pituitary adenomas should consider any mild signs and symptoms of functionality, particularly in cases of GH- and ACTH-secreting adenomas.

Solitary subcutaneous sarcoidosis with massive chronic prepatellar bursal involvement

A 56-year-old man presented with a painless prepatellar mass of the left knee. MR images demonstrated a large, well-defined mass with heterogeneous intermediate signal intensity on T1- and proton density-weighted images. Mild, heterogeneous enhancement was noted after the intravenous administration of gadolinium. Diagnostic imaging included atypical soft-tissue infection, fibrogranulomatous reaction, gouty tophus, rheumatoid nodule and xanthoma or possibly malignancy. The histopathological examination revealed sarcoidosis involving the prepatellar bursa.

MR imaging assessment of inflammatory, crystalline-induced, and infectious arthritides

The role of magnetic resonance imaging in evaluating patients with inflammatory arthritides has evolved with the recent introduction of drugs capable of modifying disease activity and natural history. In conditions like rheumatoid arthritis, active synovitis and bone marrow inflammation precede and predict bone and cartilage erosion. These imaging findings identify patients who can be treated early and aggressively to prevent future morbidity. Similarly, in gout and other crystalline disorders, specific diagnosis aided by imaging may lead to earlier medical and surgical management. Infected joints need the most rapid identification to institute immediate therapy and prevent irreversible cartilage destruction.

Pseudotumoural soft tissue lesions of the foot and ankle: a pictorial review

In the foot and ankle region, benign neoplasms and pseudotumoural soft tissue lesions are significantly more frequent than malignant tumours. The pseudotumoural lesions constitute a heterogeneous group, with highly varied aetiology and histopathology. This article reviews the imaging features of the most common pseudotumours of the soft tissues in the foot and ankle. Although the imaging characteristics of several of the lesions discussed are non-specific, combining them with lesion location and clinical features allows the radiologist to suggest a specific diagnosis in most cases.

Large benign rheumatoid nodules of the trunk in an elderly patient: radiologic appearance mimicking a soft-tissue sarcoma

An 80-year-old woman without any evidence of rheumatoid arthritis presented with two large (maximum diameter: 6 cm and 7 cm), rapidly growing, rubbery nodules on the trunk. Although the clinical and radiological appearance suggested malignancy, the nodules were pathologically identical to rheumatoid nodules in rheumatoid arthritis, and the nodules regressed spontaneously. The final diagnosis was benign rheumatoid nodules. Recognition of this rare clinical entity is important to avoid unnecessary examination and treatment.

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.

Painful heel: MR imaging findings

Heel pain is a common and frequently disabling clinical complaint that may be caused by a broad spectrum of osseous or soft-tissue disorders. These disorders are classified on the basis of anatomic origin and predominant location of heel pain to foster a better understanding of this complaint. The disorders include plantar fascial lesions (fasciitis, rupture, fibromatosis, xanthoma), tendinous lesions (tendinitis, tenosynovitis), osseous lesions (fractures, bone bruises, osteomyelitis, tumors), bursal lesions (retrocalcaneal bursitis, retroachilleal bursitis), tarsal tunnel syndrome, and heel plantar fat pad abnormalities. With its superior soft-tissue contrast resolution and multiplanar capability, magnetic resonance (MR) imaging can help determine the cause of heel pain and help assess the extent and severity of the disease in ambiguous or clinically equivocal cases. Careful analysis of MR imaging findings and correlation of these findings with patient history and findings at physical examination can suggest a specific diagnosis in most cases. The majority of patients with heel pain can be successfully treated conservatively, but in cases requiring surgery (eg, plantar fascia rupture in competitive athletes, deeply infiltrating plantar fibromatosis, masses causing tarsal tunnel syndrome), MR imaging is especially useful in planning surgical treatment by showing the exact location and extent of the lesion.

Subcutaneous granuloma annulare: MR imaging features in six children and literature review

PURPOSE

To describe the magnetic resonance (MR) imaging findings of subcutaneous granuloma annulare (SGA), a rare mass of early childhood.

MATERIALS AND METHODS

MR imaging studies and clinical records in six children aged 2 1/2-4 years in whom SGA was diagnosed between 1993 and 1997 were retrospectively reviewed. All MR imaging examinations included T1-weighted and fast spin-echo T2-weighted sequences. Three children received intravenous contrast material. The diagnosis was established by using excisional biopsy results, with confirmation by means of characteristic features in mucin-stained specimens.

RESULTS

All children presented with a nontender, nonmobile mass. The lesion in all six children was confined to the pretibial (n = 5) or prepatellar (n = 1) soft tissues. MR imaging characteristics were uniform. Masses were subcutaneous in location and had ill-defined margins. On T1-weighted images, the lesion was isointense or slightly hyperintense to muscle. On T2-weighted images, the signal intensity was more heterogeneous, but the lesion was predominantly hyperintense. In three children who received contrast material, the lesion enhanced nearly homogeneously.

CONCLUSION

Although SGA can often be diagnosed on the basis of clinical characteristics, MR imaging may be requested by practitioners unfamiliar with the lesion. In these cases, with recognition of typical MR imaging features, a limited biopsy and specific histologic preparation that includes mucin staining can be recommended.