Case report 710: Symmetrical eosinophilic granuloma of the lower extremities (proven) and Erdheim-Chester disease (probable).

We present a case of symmetrical EG of the lower extremities in a 36-year-old man. Several entities are considered in the differential diagnosis. However, many of the features bear a striking resemblance to ECD, which probably coexists in this case. A link between the two entities, EG and ECD, has been suggested by others. Future experience may confirm this hypothesis.

Juxta-articular large cell lymphoma.

Three patients with juxta-articular large cell lymphoma presented as suffering from monarthropathies. A spectrum of radiographic changes was observed that included subchondral sclerosis, regional osteopenia, effusion, and mottled lytic changes in the juxta-articular region of the affected joint. MRI was performed in two patients. In one, it revealed a high signal mass on T2-weighted sequences. In the second, a mass bridging the joint was demonstrated which was difficult to appreciate on CT and was not visible radiographically. In all cases, biopsies revealed large cell non-Hodgkin's lymphoma of bone. We present these studies to emphasize this unusual pattern of non-Hodgkin's lymphoma as well as to demonstrate the contribution of MRI to the diagnosis.

The enthesopathic changes of hypophosphatemic osteomalacia in adults: radiologic findings.

The enthesopathy (bone proliferation at sites of ligament, tendon, joint capsule, and interosseous membrane attachment) that may be present in adults who have longstanding hypophosphatemic osteomalacia, the most common type of osteomalacia, has received little attention in the radiologic literature. These proliferative enthetic changes may be associated with various musculoskeletal symptoms. The spectrum of proliferative enthesopathic changes, involving the axial and appendicular skeleton, is described in six patients 18-63 years old. Proliferative changes at the attachment of the annulus fibrosus were present in six of six patients and ranged in extent from tiny hyperostoses at a few levels to thin marginal symmetric syndesmophytes involving the entire lumbosacral spine and mimicking spondylitis. Thoracic spinal syndesmophytes were present in four patients and cervical hyperostoses of various magnitudes were present in three patients. Changes in the sacroiliac joints were present in four of six patients and varied from mild widening to symmetric intraarticular and anterior paraarticular bony bridging. Proliferative enthesopathy involving the pelvis and proximal femora was present in six of six patients. Appendicular changes included accessory ossicles within the wrist and hands and bony proliferation of the distal radius and metacarpal heads. These were noted in four patients. Ossification of the interosseous membrane of the forearms or the lower extremities was present in six patients and paraarticular bony proliferation about the elbows was noted in four patients. It is apparent that the severity of the enthesopathy that occurs may vary, and that hypophosphatemic osteomalacia should be recognized as a cause of enthesopathy even if other radiographic findings of osteomalacia may not be present on available radiographs.

A unified approach to symptomatic juxtasternal arthritis and enthesitis.

Symptomatic arthritic and enthesopathic conditions of the sternum and its articulations have not been studied well as a group, despite previous reports of individual diseases and radiographic abnormalities that affect these structures. The lack of a unified clinical approach has been partly due to the absence of a name for the clinical condition, which we propose to call juxtasternal arthro-osteitis. Although juxtasternal arthro-osteitis may be caused by septic arthritis, this study was based on 24 adult patients with noninfectious juxtasternal arthro-osteitis, collected retrospectively from records of patients who had sternal tomography and from rheumatology clinic populations. Twelve of the patients had an underlying systemic arthropathy that met standard diagnostic criteria; three patients had an unclassifiable systemic arthropathy; and nine patients had the idiopathic localized disease, which has been termed sternocostoclavicular hyperostosis. Radiographic findings in the various diseases followed definite trends, but were not sufficiently distinct to provide the sole basis for diagnosis. Initial failure to correlate dermatologic, rheumatologic, radiographic, and laboratory findings led to prolonged delays in diagnosis in many cases. When juxtasternal arthro-osteitis is encountered, a thorough evaluation should be made for systemic disease. Idiopathic sternocostoclavicular hyperostosis can be diagnosed only after systemic arthropathy or enthesopathy has been excluded.

Primary tumors of the foot: MR imaging.

The findings at magnetic resonance (MR) imaging of eight patients with primary tumors of the foot were compared with those at gross pathologic examination. In all cases, there was excellent correlation between the two studies. When compared with computed tomography (CT), MR imaging was superior in defining the presence and extent of local disease. While the appearances of various foot neoplasms are nonspecific, the ease of multiplanar imaging, the superior contrast resolution, and the sensitivity to marrow abnormalities are major advantages of MR imaging over CT in staging foot neoplasms. These advantages are crucial when foot-sparing curative resection of a malignancy is contemplated. The combination of plain radiography and MR imaging may be all that is necessary for optimal preoperative detection and local staging of tumors of the foot.

Diaphyseal bone disease: scintigraphic-radiographic correlation.

Though generally nonspecific, the patterns of diaphyseal uptake of bone seeking radionuclides, when correlated with the radiographic findings and clinical histories, often suggest specific diagnoses and may obviate the need for further imaging. Diaphyseal uptake is considered in terms of "hot spots," unilateral long segment lesions and bilateral processes that may be symmetric or asymmetric in distribution. Scintigrams and corresponding radiographs of 18 different lesions are illustrated.

Anteroposterior radiographic view of the knee. An unreliable indicator of bone damage.

The clinician and/or radiologist uses standard radiographic views to assess bony changes in the joints of patients with both potential and established arthritis. Using AP (standing) views, we recorded the number of osteophytes and/or subchondral cysts seen on both nonarthritic and arthritic tibial tables and their respective plateaus. These data were compared with the number of osteophytes and/or subchondral cysts observed on "en face" views taken of the same tibial tables after they were resected from the knee joints. Not all of the osteophytes or subchondral cysts present in these tibial tables were detected with the AP view. Narrow osteophytes and those located at extreme anterior or posterior positions on a plateau were missed. Single cysts scattered across a plateau were also not seen. We found that the standard AP view gave an inaccurate measure of the amount of bone damage actually present in the tibial tables of arthritic knees.

Skeletal metastases.

This article discusses the role of imaging in the evaluation of patients with known or suspected malignancies. The radionuclide skeletal scintigram is the most sensitive imaging method for screening the skeleton for metastatic disease but is inherently nonspecific. Standard radiography provides useful correlative information and often confirms the presence of malignancy when characteristic lytic or blastic lesions are seen. Newer modalities such as CT and MR do not have a primary role in detecting skeletal metastases but may reveal lesions incidentally.

Disseminated migratory osteoporosis: an unusual pattern of osteoporosis.

Regional migratory osteoporosis (RMO) is a well-defined clinical entity, consisting of migratory osteoporosis involving the lower extremities with associated radiographic changes. Idiopathic osteoporosis (IO) is considered to be a separate and distinct entity, occurring in young adults and consisting of axial osteoporosis and back pain. We describe a patient who had hybrid characteristics, both clinically and radiographically, and include iliac-crest biopsy histologic correlation. We believe that this pattern of osteoporosis in many ways resembles RMO, but with severe axial involvement; hence the term disseminated migratory osteoporosis.

Ribbing's disease: radiographic-scintigraphic correlation and comparative analysis with Engelmann's disease.

Engelmann's disease is an uncommon condition characterized radiographically by symmetric diaphyseal sclerosis involving predominantly the tubular bones. Ribbing described an entity with similar but less extensive or severe changes which he thought differed sufficiently to constitute a distinct process. We present two cases of Ribbing's disease and one of Engelmann's disease, emphasizing the differences between the two. Radiographic-scintigraphic correlation is provided to demonstrate the value of skeletal scintigraphy in cases of Ribbing's disease and progressive diaphyseal dysplasia.

Acne-associated spondylarthropathy: radiographic features.

Experience with six patients with severe acne and associated axial and peripheral arthritis is described. Four of the patients had a dermatologic triad of severe acne, hidradenitis suppurativa, and dissecting cellulitis of the scalp, the so-called follicular occlusion triad. All were black men with episodic peripheral arthropathy and low back pain. One had inflammatory bowel disease. Rheumatoid factor and HLA-B27 were absent in five patients who had these determinations. An erosive and proliferative arthritis of the axial and appendicular skeleton is described. The radiographic findings were indistinguishable from those of the seronegative spondylarthropathies. We found no previous reports in the radiologic literature describing this articulocutaneous entity.

Atypical insufficiency fractures confused with Looser zones of osteomalacia.

Six women, aged 24-67 years, had osteopenia and insufficiency fractures, which suggested a diagnosis of osteomalacia. The insufficiency fractures occurred at traditional sites for Looser zones, were multiple in number, were symmetrically distributed in three patients, and did not heal promptly. Bone mass was low, as assessed by single-energy photon absorptiometry at the midshaft of the radius. Two postmenopausal women had vertebral compression fractures. Biochemical indices and bone histomorphometric analysis excluded osteomalacia, and in vivo double tetracycline labeling in five patients revealed both high and low bone turnover states. We propose more stringent radiographic criteria for the designation of the term "Looser zone" that retains the customary association between the radiologic event and osteomalacia. This paper also outlines a diagnostic strategy for future cases of atypical insufficiency fractures and proposes reasons for their resemblance to true Looser zones.