Legg-Calve-Perthes' disease: an opportunity to prevent blindness?

Legg-Calve-Perthes' disease (LCP) is defined as avascular necrosis of the femoral head in a child and may present to a variety of disciplines from general practice to orthopaedics, paediatrics, rheumatology and more. The Stickler syndromes are a group of disorders of type II, IX and XI collagen associated with hip dysplasia, retinal detachment, deafness and cleft palate. The pathogenesis of LCP disease remains an enigma but there have been a small number of cases reporting variants in the gene encoding the α1 chain of type II collagen (COL2A1). Variants in COL2A1 are known to cause type 1 Stickler syndrome (MIM 108300, 609508), which is a connective tissue disorder with a very high risk of childhood blindness, and it is also associated with dysplastic development of the femoral head. It is unclear whether COL2A1 variants make a definitive contribution to both disorders, or whether the two are indistinguishable using current clinical diagnostic techniques. In this paper, we compare the two conditions and present a case series of 19 patients with genetically confirmed type 1 Stickler syndrome presenting with a historic diagnosis of LCP. In contrast to isolated LCP, children with type 1 Stickler syndrome have a very high risk of blindness from giant retinal tear detachment, but this is now largely preventable if a timely diagnosis is made. This paper highlights the potential for avoidable blindness in children presenting to clinicians with features suggestive of LCP disease but with underlying Stickler syndrome and proposes a simple scoring system to assist clinicians.

Homozygous Type IX collagen variants (COL9A1, COL9A2, and COL9A3) causing recessive Stickler syndrome-Expanding the phenotype.

Stickler syndrome (SS) is characterized by ophthalmic, articular, orofacial, and auditory manifestations. SS is usually autosomal dominantly inherited with variants in COL2A1 or COL11A1. Recessive forms are rare but have been described with homozygous variants in COL9A1, COL9A2, and COL9A3 and compound heterozygous COL11A1 variants. This article expands phenotypic descriptions in recessive SS due to variants in genes encoding Type IX collagen. Clinical features were assessed in four families. Genomic DNA samples derived from venous blood were collected from family members. Six affected patients were identified from four pedigrees with variants in COL9A1 (one family, one patient), COL9A2 (two families, three patients), and COL9A3 (one family, two patients). Three variants were novel. All patients were highly myopic with congenital megalophthalmos and abnormal, hypoplastic vitreous gel, and all had sensorineural hearing loss. One patient had severe arthropathy. Congenital megalophthalmos and myopia are common to dominant and recessive forms of SS. Sensorineural hearing loss is more common and severe in recessive SS. We suggest that COL9A1, COL9A2, and COL9A3 be added to genetic screening panels for patients with congenital hearing loss. Although recessive SS is rare, early diagnosis would have a high impact for children with potentially dual sensory impairment, as well as identifying risk to future children.

L1 vertebral density on CT is too variable with different scanning protocols to be a useful screening tool for osteoporosis in everyday practice.

OBJECTIVE: To determine whether a single L1 density threshold can be used to screen all patients undergoing CT at a busy tertiary referral centre for those at risk of osteoporosis. METHODS: 200 patients, who had been randomly selected for an audit of CT reporting of incidental vertebral fractures, had their L1 density measured on 864 routine CT examinations. These had been performed with a variety of kVp and intravenous (i.v.) contrast protocols, reflecting the wide range of imaging indications. RESULTS: L1 density measured on thick axial, thin axial or sagittal images had an excellent intraclass correlation coefficient (0.996). For the same patients imaged twice within 6 months, there was mean intraexamination L1 density difference of 27.5 HU. Variability due to i.v. contrast medium administration resulted in a mean difference of 24.5 HU. Mean difference due to acquisition kVp was 24.1 HU. Once matched for sex, age, kVp and i.v. contrast, there was a significant difference between the L1 density in patients with vertebral fractures compared to those without fractures (mean 30.19 HU). CONCLUSION: There is significant variability in the L1 vertebral body CT density due to differences in acquisition variables such as kVp and timing post-i.v. contrast medium. Advances in knowledge: Previous studies suggested that L1 CT density could be used to screen for osteoporosis. The current study cautions that it is not possible to define a single L1 density threshold for screening, due to the number of variables within a wide range of scanning protocols for different imaging indications in everyday practice.

A Comprehensive Single Institutional Review of 2 Years in a Designated Fast-Track Sarcoma Diagnostic Clinic Linked with a Sarcoma Specialist Advisory Group: Meeting the Target but Failing the Task?

Background. National guidelines prompted the implementation of a designated two-week wait referral pathway to facilitate the early diagnosis of sarcomas, to improve treatment outcomes. Methods. Patients referred to the Cambridge Sarcoma Diagnostic Clinic between January 2013 and December 2014 were identified through the electronic appointments system. Information was retrospectively retrieved about patient characteristics and details of the diagnostic pathway. Results. 17.3% of patients referred (69/397) were diagnosed with a malignancy. Of these, 59.3% (41/69) had primary sarcomas, 17.4% (12/69) had metastatic cancer, and 23.2% (16/69) had a different primary malignancy. 15% of the 41 sarcomas were <5 cm, 34% in the 5-10 cm range, and 51% >10 cm. Sarcomas diagnosed through this clinic represented 13% (41/315) of sarcomas managed at the centre during the same 2 years. Conclusion. While we achieved the target of 10% (41/397) sarcoma diagnosis rate in the rapid access clinic, only 15% of these were <5 cm better prognosis lesions. This calls into question the "real world" impact of such diagnostic clinics on early diagnosis of sarcomas. In order to enhance generic cancer diagnostic skills, training in these diagnostic clinics could be usefully integrated into national training curricula for both surgical and nonsurgical oncologists.

Foreign body granulomatous reaction associated with polyethelene 'Fiberwire(®)' suture material used in Achilles tendon repair.

Repair of acute Achilles tendon rupture is a common procedure. There are many accepted surgical techniques; suture selection is largely due to surgeon preference. We present a case report of a granulomatous reaction to suture material following Achilles tendon repair. 'Fiberwire(®)' is an increasingly popular suture material for the repair of tendons and ligamentous structures; the polyethelene braided structure with silicone and polyester coating provides high tensile strengths and good handling characteristics. Eight months following uneventful Achilles tendon repair surgery in an otherwise fit and well patient, pain, swelling and loss of function was noted. She required revision surgery with debridement and reconstruction of the tendo Achillis with flexor hallucis longus tendon transfer. Histology revealed a granulomatous reaction with giant cell response surrounding sections of the suture. Both the silicone coating of Fiberwire(®) and polyethylene core have the potential to cause a severe granulomatous reaction. We would advise caution in the use of this suture for tendo Achillis repair, and use the readily available alternatives.

Validation of clinical examination versus magnetic resonance imaging and arthroscopy for the detection of rotator cuff lesions.

Limited evidence exists regarding the validity of clinical examination for the detection of shoulder pathology. We therefore wished to establish the sensitivity, specificity, positive predictive value and negative predictive value of clinical tests and magnetic resonance imaging (MRI) in the diagnosis of rotator cuff disorders against findings at arthroscopy. Using recognised tests for specific shoulder lesions, 117 patients with shoulder symptoms awaiting surgery were examined in a standard manner. The diagnoses were categorised and compared with abnormalities found on MRI and at surgery. Results were cross-tabulated to determine the above parameters. Ninety-four patients formed the study group with a mean age of 51 years. The median duration of symptoms was 45 weeks. For clinical examination, sensitivity and specificity to detect a tear or rupture of supraspinatus were 30 % (16/54) and 38 % (15/40) and, for the detection of any pathology, were 94 % (67/71) and 22 % (5/23), respectively, compared with arthroscopy. Correspondingly, the sensitivity of MRI compared with arthroscopy to detect a tear or rupture of supraspinatus was 90 % (28/31) with a specificity of 70 % (46/53), whereas for the detection of any abnormality, the sensitivity was 92 % (65/71) with a specificity of 48 % (11/23). The sensitivity of detecting any rotator cuff abnormality is high when examination and MRI is compared with arthroscopy with the specificity being greater with MRI than examination. In patients with shoulder symptoms severe enough to consider surgery, clinical assessment followed by specific imaging may help define the pathology in order to direct appropriate management.

Multicentre trial of weekly risedronate on bone density in adults with cystic fibrosis.

BACKGROUND: The aim of this study was to assess the efficacy, tolerability and safety of risedronate in adults with CF. METHODS: Patients with a lumbar spine (LS), total hip (TH) or femoral neck (FN) bone mineral density (BMD) Z-score of -1 or less were randomised to receive risedronate 35 mg weekly or placebo, and calcium (1g)+vitamin D(3) (800IU). RESULTS: At baseline, BMD Z-scores in the risedronate (n=17) and placebo (n=19) groups were similar. By 24 months, 7/17 risedronate patients vs 0/19 placebo patients stopped the study medication due to bone pain. After 24 months treatment, the mean difference (95% CI) in change in LS, TH and FN BMD between the risedronate vs placebo groups was 4.3% (0.4, 8.2) p=0.03; 4.0% (-0.5, 8.6) p=0.08; and 2.4% (-3.5, 8.2) p=0.41. CONCLUSIONS: After two years treatment there was a significant increase in LS BMD with weekly risedronate compared to placebo.

Osseous manifestations of adult Gaucher disease in the era of enzyme replacement therapy.

Enzyme replacement therapy (ERT) for Gaucher disease with mannose-terminated glucocerebrosidase has proved its therapeutic position with salutary effects on hematologic abnormalities, visceral infiltration, and quality of life. The frequency of new bone complications is reduced but not eliminated. Established osteonecrosis is beyond salvage. A systematic description of the burden of bone manifestations, persisting despite ERT, should inform future remedial strategies. Thus, we conducted this study to quantify the burden of residual skeletal disease and to explore putative relationships between clinical, radiologic, and biochemical factors and bone sequelae associated with disability.Consecutive adult patients attending 3 referral centers in the United Kingdom were invited to participate. A representative group of 100 patients agreed to a structured interview, clinical examination, radiologic review, and completion of questionnaires. Osteonecrosis was evident in 43%, Erlenmeyer flask deformity in 59%, fragility fracture in 28%, osteomyelitis in 6%, and lytic lesions in 4%. Mobility was impaired in 32% of patients, while 15% experienced significant pain. The EuroQol 5D (EQ5D) quality of life summary measure was reduced and was associated with osteonecrosis and fragility fracture. Eight patients experienced new osteonecrosis after the start of ERT, though the presentation and evolution were often atypical. Nine patients had been treated from childhood and had an excellent outcome. Osteonecrosis was associated with age of presentation and with splenectomy-indeed, we observed a strong temporal association between splenectomy and incidence of osteonecrosis.The biomarkers PARC/CCL18 and chitotriosidase were associated with prevalent osteonecrosis, and, in particular, with osteonecrosis occurring despite treatment. This study documents significant residual skeletal pathology and disability in patients in the mature phase of their treatment in a developed region. The temporal association between splenectomy and osteonecrosis implies causation. The relationship between clinical and biochemical markers and existing bone complications sets the scene for future prospective studies that will focus on management strategies informed by credible assessment of risk.

Compartment syndromes.

Compartment syndrome can be defined as increased tissue pressure within a closed myofascial space, resulting in disturbed microcirculation and the potential for irreversible neuromuscular ischemic damage. It may present either acutely or chronically. Acute compartment syndrome most commonly occurs following lower limb trauma, and emergency decompression through open and extensive fasciotomies is the treatment of choice. There is little place for imaging in the acute setting because the diagnosis should be made on clinical grounds, possibly supported by measurements of compartmental pressure. Chronic compartment syndrome is more common, usually presenting with recurrent episodes of pain on exercise. The demonstration of elevated compartment pressures following exercise is currently the gold standard method for diagnosis. There is increasing interest in the use of imaging as either a potential alternative to compartmental pressure measurement or as an initial screening investigation prior to invasive testing. The literature evaluating the use of imaging techniques is reviewed, with an emphasis on the potential role of postexertional magnetic resonance imaging.

Changing structure of the femoral neck across the adult female lifespan.

The anatomic distribution of cortical and cancellous bone in the femoral neck may be critical in determining resistance to fracture. We investigated the effects of aging on femoral neck bone in women. In this cross-sectional study, we used clinical multidetector computed tomography (MDCT) of the hips to investigate aging effects in 100 female volunteers aged 20 to 90 years. We developed a clinically efficient protocol to measure cortical thickness (C.Th) and cortical, trabecular, and integral bone mineral density (CtBMD, TrBMD, and iBMD in mg/cm(3)) in anatomic quadrants of the femoral neck. We used a nested ANOVA to evaluate their associations with height, weight, location in the femoral neck, and age of the subject. Age was the principal determinant of both cortical thickness and BMD. Age had significantly different effects within the anatomic quadrants; compared with young women, elderly subjects had relative preservation of the inferoanterior (IA) quadrant but strikingly reduced C.Th and BMD superiorly. A model including height, weight, and region of interest (and their interactions) explained 83% of the measurement variance (p < .0001). There were marked C.Th and BMD differences between age 25 and age 85 in the already thin superior quadrants. At 25 years the predicted C.Th of the superoposterior quadrant was 1.63 mm, whereas at 85 years it was 0.33 mm [-1.33 mm, 95% confidence interval (CI) of difference over 60 years -1.69 to -0.95]. By contrast, at 25 years mean C.Th of the IA quadrant was 3.9 mm, whereas at 85 years it was 3.3 mm (-0.6 mm, 95% CI -0.83 to -0.10). CtBMD of the IA region was equivalent at 25 and 85 years. In conclusion, elderly women had relative preservation of IA femoral neck bone over seven decades compared with young women but markedly lower C.Th and BMD in the other three quadrants. The IA quadrant transmits mechanical load from walking. Mechanical theory and laboratory tests on cadaveric femurs suggest that localized bone loss may increase the risk of fracture in elderly fallers. It remains to be determined whether this MDCT technique can provide better prediction of hip fracture than conventional clinical dual X-ray absorptiometry (DXA).

MR-guided direct arthrography of the hip.

PURPOSE: To develop an MR-guided technique for direct magnetic resonance arthrography (DMRA) of the hip using a conventional 1.5 Tesla (T) MRI scanner. MATERIALS AND METHODS: Interactive versions of standard single-shot fast spin echo, coherent gradient echo, and fully balanced steady-state free precession sequences were developed, together with the ability to operate the scanner from within the magnet room. Initial optimization was performed using ex vivo animal joints. After informed consent, five patients underwent DMRA using dilute gadolinium as the contrast medium. RESULTS: The procedure was successful in all five patients and diagnostic quality MR arthrography studies were obtained in all cases. The time taken from the initial placement of skin marker to the introduction of contrast medium reduced with successive patients: 26, 22, and 19 min with the final two studies taking 13 min each. CONCLUSION: This work demonstrates the feasibility of performing DMRA using MR guidance, avoiding the need for X-ray fluoroscopy facilities but exploiting the available imaging performance of a high-field closed-bore MR system. The use of an in room control and display system together with interactive fluoroscopic imaging sequences simplifies the positioning of the needle and allows rapid confirmation of an intra-articular injection.

Imaging modalities in the evaluation of soft tissue complaints.

A number of imaging modalities are available for the assessment of soft tissue complaints. The strengths and advantages of each modality must be seen in the context of any corresponding weakness or disadvantage. The sensitivity and specificity of the imaging technique must also be understood. In this article, each main radiological technique will be considered in turn. Fundamental technical aspects and common variations of the basic imaging theme will be explained and their relative strengths and limitations will be explored. Typical common clinical uses in the context of soft-tissue complaints will be considered.

Significant ocular findings are a feature of heritable bone dysplasias resulting from defects in type II collagen.

BACKGROUND/AIMS: The type II collagenopathies are a phenotypically diverse group of genetic skeletal disorders caused by a mutation in the gene coding for type II collagen. Reports published before the causative mutations were discovered suggest heritable bone dysplasias with skeletal malformations may be associated with a vitreoretinopathy. METHODS: A retrospective notes search of patients with a molecularly characterised type II collagenopathy chondrodysplasia who had been examined in the ophthalmology clinic was conducted. RESULTS: 13 of 14 patients had a highly abnormal vitreous appearance. One patient aged 11 presented with a total retinal detachment. Two other children aged 2 and 4 had bilateral flat multiple retinal tears on presentation. 10 of 12 patients refracted were myopic. Two patients had asymptomatic lens opacities: one associated with bilateral inferiorly subluxed lenses and the other with a zonule and lens coloboma. CONCLUSION: Heritable skeletal disorders resulting from a mutation in the gene coding for type II collagen are associated with abnormal vitreous, myopia and peripheral cataract with lens subluxation. In bone dysplasias resulting from a defect of type II collagen there is likely to be a high risk of retinal detachment with a propensity to retinal tears at a young age.

Soft-tissue masses in the shoulder girdle: an imaging perspective.

We discuss the radiological assessment of soft-tissue masses presenting in the shoulder girdle and emphasise the relative strengths and weaknesses of the different imaging modalities available. The appearances of the common benign and malignant soft-tissue tumours are presented together with conditions that present with specific imaging features around the shoulder region.

An international survey of hospital practice in the imaging of acute scaphoid trauma.

OBJECTIVE: Scaphoid fractures are relatively common. If not treated promptly there may be risk of long-term disability. However, unnecessary wrist immobilization is inconvenient and may hinder professional activities. Therefore, early accurate diagnosis is essential. Currently, the American College of Radiology deems MRI and radiographs as the most appropriate investigations in imaging acute scaphoid trauma. Our objective was to assess scaphoid imaging protocols. MATERIALS AND METHODS: To assess scaphoid imaging protocols, an international survey of imaging practice was performed. Two hundred hospitals worldwide were sent a survey regarding their scaphoid trauma imaging protocols. Only replies from hospitals that had full CT, MRI, and scintigraphy facilities were accepted. RESULTS: Data were obtained from 105 hospitals, of which 23 had fixed protocols. The number of scaphoid radiographic views varied from two to six. Before second-line investigations were initiated, repeat radiographs were usually performed in 76 of the 105 hospitals. In 29 hospitals, other imaging techniques were used without further radiography. The usual second-line investigation was MRI in 31/105, CT in 19/105, and scintigraphy in 14/105. Further protocols included CT or MRI in 10/105, CT or scintigraphy in 6/105, scintigraphy or MRI in 6/105, CT then MRI (if CT was negative) in 1/105, both CT and scintigraphy in 1/105, and scintigraphy then CT (if positive) in 1/105. There was equal preference among MRI, CT, and scintigraphy in 10/105 centers, and clinical examination and radiographs were used alone in 6/105. CONCLUSION: The survey reveals marked inconsistency in the imaging of acute scaphoid injury. Although other factors may have played a role, limited scientific evidence regarding the ideal imaging in acute scaphoid trauma may be the root of this inconsistency.

MRI of the ankle: effect on diagnostic confidence and patient management.

OBJECTIVE: The purpose of our study was to quantify the impact that MRI of the ankle has on a surgeon's diagnosis and diagnostic confidence and on patient management. SUBJECTS AND METHODS: A prospective controlled observational study was performed with 91 consecutive referrals (53 males, 38 females; age range, 13-76 years; mean age, 40.6 years) from a single orthopedic foot and ankle surgeon to a regional teaching hospital for ankle MRI. Measurements of diagnostic confidence using a visual analogue scale (VAS) were made both before and after the MRI examination in each case. Proposed management was also recorded before imaging and then with benefit of the MRI result. Finally, the surgeon provided a subjective statement regarding the perceived usefulness of the MRI examination when the patient was subsequently reviewed in the clinic. RESULTS: There was a significant overall change in diagnostic confidence in 65 (71%) cases. The number of diagnoses reduced from an average per patient of 2.3 (95% CI, 2.09-2.44) to 1.2 (95% CI, 1.05-1.39), and in 157 (69%) of all diagnoses entertained, there was a significant change in the confidence with which they were considered after imaging. Management plans changed in 32 (35%) of the patients, and in 31% of those patients for whom plans were changed, a less invasive plan was adopted. Overall, the surgeon thought that understanding of the patient's disease had either depended on MRI or had been substantially improved by it in 60 (66%) cases. CONCLUSION: MRI of the ankle influences clinicians' diagnoses and management plans.

Rheumatoid arthritis is associated with increased aortic pulse-wave velocity, which is reduced by anti-tumor necrosis factor-alpha therapy.

BACKGROUND: Rheumatoid arthritis (RA) is associated with increased cardiovascular risk, which is not explained by traditional cardiovascular risk factors but may be due in part to increased aortic stiffness, an independent predictor of cardiovascular mortality. In the present study, our aim was to establish whether aortic stiffness is increased in RA and to investigate the relationship between inflammation and aortic stiffness. In addition, we tested the hypothesis that aortic stiffness could be reduced with anti-tumor necrosis factor-alpha (TNF-alpha) therapy. METHODS AND RESULTS: Aortic pulse-wave velocity (PWV), augmentation index, and blood pressure were measured in 77 patients with RA and in 142 healthy individuals. Both acute and chronic inflammatory measures and disease activity were determined. The effect of anti-TNF-alpha therapy on PWV and endothelial function was measured in 9 RA patients at 0, 4, and 12 weeks. Median (interquartile range) aortic PWV was significantly higher in subjects with RA than in control subjects (8.35 [7.14 to 10.24] versus 7.52 [6.56 to 9.18] m/s, respectively; P = 0.005). In multiple regression analyses, aortic PWV correlated independently with age, mean arterial pressure, and log-transformed C-reactive protein (R2 = 0.701; P < 0.0001). Aortic PWV was reduced significantly by anti-TNF-alpha therapy (8.82+/-2.04 versus 7.94+/-1.86 versus 7.68+/-1.56 m/s at weeks 0, 4, and 12, respectively; P < 0.001); concomitantly, endothelial function improved. CONCLUSIONS: RA is associated with increased aortic stiffness, which correlates with current but not historical measures of inflammation, suggesting that increased aortic stiffness may be reversible. Indeed, anti-TNF-alpha therapy reduced aortic stiffness to a level comparable to that of healthy individuals. Therefore, effective control of inflammation may be of benefit in reducing cardiovascular risk in patients with RA.

High efficiency of mutation detection in type 1 stickler syndrome using a two-stage approach: vitreoretinal assessment coupled with exon sequencing for screening COL2A1.

Stickler syndrome is a genetically heterogeneous disorder that affects the ocular, skeletal, and auditory systems. To date three genes, COL2A1, COL11A1, and COL11A2, encoding the heterotypic type II/XI collagen fibrils present in vitreous and cartilage have been shown to have mutations that result in Stickler syndrome. As systemic features in this disorder are variable we have used an ophthalmic examination to differentiate those patients with a membranous vitreous phenotype associated with mutations in COL2A1, from other patients who may have mutations in other genes. Gene amplification and exon sequencing was used to screen 50 families or sporadic cases with this membranous phenotype, for mutations in COL2A1. Mutations were detected in 47 (94%) cases consisting of 166 affected and 78 unaffected individuals. We also demonstrate that the predominantly ocular form of type 1 Stickler syndrome is not confined to mutations in the alternatively spliced exon 2. Using splicing reporter constructs we demonstrate that a mutant GC donor splice site in intron 51 can be spliced normally; this contributed to the predominantly ocular phenotype in the family in which it occurred.

Can 16-detector multislice CT exclude skeletal lesions during tumour staging? Implications for the cancer patient.

Current imaging guidelines recommend that many cancer patients undergo soft-tissue staging by computed tomography (CT) whilst the bones are imaged by skeletal scintigraphy (bone scan). New CT technology has now made it feasible, for the first time, to perform a detailed whole-body skeletal CT. This advancement could save patients from having to undergo duplicate investigations. Forty-three patients with known malignancy were investigated for bone metastasis using skeletal scintigraphy and 16-detector multislice CT. Both studies were performed within six weeks of each other. Whole-body images were taken 4 h after injection of 500 Mbq (99m)Tc-MDP using a gamma camera. CT was performed on a 16-detector multislice CT machine from the vertex to the knee. The examinations were reported independently and discordant results were compared at follow-up. Statistical equivalence between the two techniques was tested using the Newcombe-Wilson method within the pre-specified equivalence limits of +/-20%. Scintigraphy detected bone metastases in 14/43 and CT in 13/43 patients. There were seven discordances; four cases were positive on scintigraphy, but negative on CT; three cases were positive on CT and negative on scintigraphy. There was equivalence between scintigraphy and CT in detecting bone metastases within +/-19% equivalence limits. Patients who have undergone full whole-body staging on 16-detector CT may not need additional skeletal scintigraphy. This should shorten the cancer patient's diagnostic pathway.

Giant atypical ossifying fibromyxoid tumour of the calf.

We present a case of giant atypical ossifying fibromyxoid tumour (OFMT) of soft tissue, occurring in the calf, in a 77-year-old woman. The patient presented with a history of bleeding ulcer over a calf lump that had been present for over 4 years. Clinical presentation, radiological features and histopathologic findings are described, and the relevant literature is reviewed.