Ultrasonography of achilles tendons in primary hypercholesterolemia. Comparison with computed tomography

An Unusual Case of Xanthoma of Bilateral Achilles Tendon with Gouty Infiltration: A Rare Case Report

Achilles tendon xanthoma is a benign and rare disease with a high incidence in patients having familial hypercholesterolemia. Patients present with or without pain and thickened tendons. Gout is seen in patients with hyperuricemia. Coexistence of xanthoma and gout is extremely rare. We searched the PubMed literature with ‘Xanthoma’ and ‘Gout’ as keywords and could find only one case report. Imaging modalities such as radiography and ultrasonography, play a vital role in diagnosing this condition early, hence helping the patient to commence the use of potentially lifesaving lipid-lowering therapeutic agents. Magnetic resonance imaging is helpful in delineating the morphological changes, exact measurements, and eventually in treatment planning. It helps to rule out early involvement of other tendons by the same pathology. We present a case of a 25-year-old male patient who presented to our institute with bilateral large symmetrical swelling in the posterior aspects of ankles for 4 years, with normal serum and blood parameters. Bilaterality, enormous size and normal blood and serum parameters make this case unique.

Achilles Tendon Softness and Thickness in Patients With Hypercholesterolemia

Background

Hypercholesterolemia is a condition where blood levels of cholesterol are high. It is of two types: The first type is familial hypercholesterolemia, which is hereditary, and the second one is due to diseases like diabetes, thyroid, etc. Achilles tendon xanthomas are noted in both types of hypercholesterolemia, which can be used as an indicator that predicts early cardiovascular disease. The aim of the study is to estimate the Achilles tendon thickness (ATT) and softness among hypercholesterolemia patients and to find the correlation between ATT and total cholesterol.

Methodology

A hospital-based cross-sectional, analytical study was done in a tertiary care hospital, Salem, for eight months. Patients of age over 18 years of both sexes who came for screening of total cholesterol in the outpatient department were included in the study. Those patients with a history of previous leg injury involving the Achilles tendon were excluded from the study. A pre-structured questionnaire was used to collect the data, and analysis was done using Statistical Package for the Social Sciences (SPSS) v20 (IBM Corp., Armonk, NY). The analysts performed the Pearson correlation test to determine the correlation between two continuous variables. A p-value of less than 0.05 was used to indicate statistical significance.

Results

In this study, there are 40 participants in the normal group and about 60 participants in the secondary hypercholesterolemia group. The mean ATT value among males and females was 9.3 and 6.1 mm, respectively. A positive correlation was noted between the ATT and total cholesterol value (p-value = 0.0001).

Conclusion

The thickness and softness of the Achilles tendon are positively correlated with the serum total cholesterol level. Males are the group where this correlation is most significant. As a result, men have a higher risk of developing Achilles tendon thickening than women. The thickness of the Achilles tendon can therefore be one of the early signs of high cholesterol levels. The clinician can utilize this indicator to evaluate early abnormal cardiac illness.

Multi-imaging study in a patient with cerebrotendinous xanthomatosis: radiology, clinic and pathology correlation of a rare condition

Cerebrotendinous xanthomatosis (CTX) is a rare metabolic disease with autosomal recessive inheritance. It is caused by mutations of the CYP27A1 gene, which codifies for sterol 27-hydroxylase, an enzyme that is responsible for the synthesis of cholic acids. In CTX, cholic acid synthesis is impaired, leading to accumulation of the precursor chenodessossicholic acid) in various organs and tissues. The clinical manifestations of CTX include chronic diarrhea, early-onset cataracts, tendon xanthomas and neurological disturbances. Therapy with oral chenodessossicholic acid has been shown to provide significantly better outcomes for affected individuals; therefore, recognition of this disease and awareness of its suggestive instrumental signs is extremely important. In this study, we describe the imaging findings in a 43-years-old male who was diagnosed with CTX and studied through ultrasound, CT and MRI.

It is important that the neurology and radiology communities are aware of this multi-imaging findings: recognition of them is important, as due to the high variability of the manifestation of this disease; it could impact on early diagnosis of a condition rarely seen, but manageable.

Diagnostic accuracy of ultrasound and MRI for Achilles tendon xanthoma in people with familial hypercholesterolemia: A systematic review

BACKGROUND

Achilles tendon xanthoma (ATX) results from tendon thickening and subclinical inflammation triggered by hypercholesterolemia, and is associated with more severe coronary artery disease and a higher risk of cardiovascular events. The ability to detect ATX by clinical examination is limited, and diagnostic imaging, for instance, using ultrasonography or magnetic resonance imagine (MRI), may improve the identification of ATX. However, the accuracy of ultrasound (US) imaging or MRI in identifying ATX in people with familial hypercholesterolemia (FH) has not been systematically reviewed.

OBJECTIVE

The objective of this study was to systematically review the accuracy of US imaging or MRI in diagnosing ATX in individuals with FH.

METHODS

Searches in Medline, Embase, Cochrane Central, and Cochrane Database of Systematic Reviews on the Ovid platform from inception to April 15, 2018, were conducted to identify articles. Any study design that included US imaging or MRI of Achilles tendon xanthoma in people with FH, and that included a control group of non-FH participants with either normal or symptomatic Achilles tendons, was considered eligible. All of the included studies were reviewed according to the STAndards for the Reporting of Diagnostic accuracy (STARD) method. A qualitative synthesis of the included studies was undertaken.

RESULTS

Fifteen studies with 699 patients with FH and 868 non-FH participants were included. Among the non-FH participants, 26 individuals had other documented Achilles tendon pathology (trauma or overuse). Evaluation with the STARD checklist suggested that the quality of evidence was low. US imaging and MRI may have acceptable sensitivity in detecting tendon thickening associated with ATX. There is a wide range in the suggested thickness thresholds and in the estimates of diagnostic accuracy.

CONCLUSIONS

A small amount of low-quality evidence suggests that ultrasonography or MRI can improve clinicians' accuracy in identifying ATX in people with FH, thereby identifying those with more severe coronary artery disease.

Ultrasonography of the Achilles Tendon in Hypercholesterolemia

The ultrasonographic (US) appearance of Achilles tendon was examined in 34 patients with hypercholesterolemia (10 with familial (FH), and 24 with secondary hypercholesterolemia (SH)), and in 22 patients with normal tendons. US findings were compared with clinical, laboratory, and radiologic results. In patients with FH, typical xanthomas in the form of hyperechoic tendinal tumors were found in only 15% while various forms of inhomogeneity of tendon structure without xanthoma formation were found in 75%. The high rate of tendon inhomogeneity may be due to the concomitant occurrence of both xanthomas and degeneration of tendon fibers. Physical examination revealed abnormalities in 60% of these patients. At CT of the tendons, abnormalities were found in 65% of the FH patients and in 40%, abnormalities were shown by plain radiography. In SH, the results did not differ significantly from normal controls. In our opinion US should be used to prove or rule out Achilles tendon abnormalities in patients with FH for prophylaxis and treatment of tendinitis and tendon rupture.

Volar morphology of the distal radius in axial planes: a quantitative analysis

To investigate the cause of rupture of the flexor pollicis longus (FPL) after volar plate fixation of distal radius fractures, previous studies have examined the shape of the distal radius in the sagittal plane or in the lateral view. However, there are no reports on the anatomical shape of the volar surface concavity of the distal radius in the axial plane. We hypothesized that this concavity might contribute to the mismatch between the plate and the surface of the radius. To test this hypothesis, we constructed three-dimensional models of the radius and FPL based on computed tomography scans of 70 normal forearms. We analyzed axial cross-sectional views with 2 mm intervals. In all cases, the volar surface of the distal radius was concave in the axial plane. The concavity depth was maximum at 6 mm proximal to the palmar edge of the lunate fossa and progressively decreased toward the proximal radius. FPL was closest to the radius at 2 mm proximal to the palmar edge of the lunate fossa. The volar surface of the distal radius was externally rotated from proximal to distal. These results may help to develop new implants which fit better to the radius and decrease tendon irritation.

Multiple tendon xanthomas in patient with heterozygous familial hypercholesterolaemia: sonographic and MRI findings

Tendon xanthomas are a component of familial hypercholesterolaemia, which is a hereditary disease and characterised by elevated low-density lipo protein cholesterol plasma levels and premature coronary artery disease. Tendon xanthomas are diagnostic for heterozygous familial hypercholesterolaemia (HFH) and they mostly occur in Achilles tendon. Sonography and MRI are superior to clinical assessment and are useful in detecting tendon xanthomas. In this report, we present ultrasonographic and MRI findings of multiple tendon xanthomas in a case of HFH.

Conditioning of the Achilles tendon via ankle exercise improves correlations between sonographic measures of tendon thickness and body anthropometry

Although conditioning is routinely used in mechanical tests of tendon in vitro, previous in vivo research evaluating the influence of body anthropometry on Achilles tendon thickness has not considered its potential effects on tendon structure. This study evaluated the relationship between Achilles tendon thickness and body anthropometry in healthy adults both before and after resistive ankle plantarflexion exercise. A convenience sample of 30 healthy male adults underwent sonographic examination of the Achilles tendon in addition to standard anthropometric measures of stature and body weight. A 10-5 MHz linear array transducer was used to acquire longitudinal sonograms of the Achilles tendon, 20 mm proximal to the tendon insertion. Participants then completed a series (90-100 repetitions) of conditioning exercises against an effective resistance between 100% and 150% body weight. Longitudinal sonograms were repeated immediately on completion of the exercise intervention, and anteroposterior Achilles tendon thickness was determined. Achilles tendon thickness was significantly reduced immediately following conditioning exercise (t = 9.71, P < 0.001), resulting in an average transverse strain of -18.8%. In contrast to preexercise measures, Achilles tendon thickness was significantly correlated with body weight (r = 0.72, P < 0.001) and to a lesser extent height (r = 0.45, P = 0.01) and body mass index (r = 0.63, P < 0.001) after exercise. Conditioning of the Achilles tendon via resistive ankle exercises induces alterations in tendon structure that substantially improve correlations between Achilles tendon thickness and body anthropometry. It is recommended that conditioning exercises, which standardize the load history of tendon, are employed before measurements of sonographic tendon thickness in vivo.

Avaliação morfométrica do tendão de Aquiles por ultra-sonografia

OBJETIVO: Determinar os valores normais dos diâmetros ântero-posterior e transversal do tendão de Aquiles na nossa população e correlacioná-los com sexo, faixa etária, cor da pele, grupo sanguíneo ABO e índice de massa corporal. MATERIAIS E MÉTODOS: Foi feita análise ultra-sonográfica de 100 tendões de Aquiles de 50 voluntários sadios, visando à mensuração dos diâmetros ântero-posterior e transversal desses tendões. Todos os exames foram realizados pelo mesmo examinador, em aparelho de ultra-sonografia com transdutor linear com freqüência de 10 MHz. RESULTADOS: Dos 50 voluntários estudados, 25 eram do sexo masculino e 25, do sexo feminino, com a faixa etária variando de 20 a 52 anos (média de 33,9 anos). O valor médio do diâmetro transversal do tendão de Aquiles foi de 13,3 ± 1,0 mm para o sexo feminino e 14,4 ± 1,4 mm para o sexo masculino; em relação ao diâmetro ântero-posterior, foi de 5,4 ± 0,5 mm para o sexo feminino e 5,6 ± 0,6 mm para o sexo masculino. Os diâmetros do tendão de Aquiles foram significativamente menores no sexo feminino (p < 0,05). Não houve diferença estatisticamente significativa entre os diâmetros ântero-posterior e transversal em relação a faixa etária, grupo sanguíneo e cor da pele. O grupo com índice de massa corporal de sobrepeso apresentou diâmetro transversal do tendão de Aquiles significativamente maior que do grupo com índice de massa corporal normal. CONCLUSÃO: Os valores médios encontrados na nossa casuística foram discordantes em relação à maioria dos estudos da literatura, demonstrando ser de grande importância a padronização e o emprego de tabelas próprias da nossa população na prática clínica diária.

The use of Achilles tendon sonography to distinguish familial hypercholesterolemia from other genetic dyslipidemias

OBJECTIVE

Achilles tendon (AT) xanthomas, specific for familial hypercholesterolemia (FH), may be clinically undetectable. We assessed the usefulness of AT sonography in the diagnosis of FH.

METHODS AND RESULTS

Sonographic AT characteristics were evaluated in 127 subjects with FH (81 genetically ascertained), 84 familial combined hyperlipidemia, 79 polygenic hypercholesterolemia, and 88 normolipidemic controls. Abnormal echostructure (sonographic xanthoma) was noted only in FH. AT thickness was higher (P<0.001) in FH men and women compared with all of the other groups and, in FH mutation carriers but not in others, correlated positively with low-density lipoprotein cholesterol (r=0.345; P<0.001) and negatively with high-density lipoprotein cholesterol (r=-0.265, P=0.015). Thickness thresholds for the diagnosis of FH with specificity >80%, as were derived from receiver operating curves, were 5.3 and 5.7 mm in men < and >45 years, and 4.8 and 4.9 mm in women < and >50 years, respectively. In FH mutation carriers, sonographic findings increased the clinical diagnosis of xanthomas from 35 (43%) to 55 (68%). Using thresholds in validation sets of 70 genetically identified FH and 54 dyslipidemic non-FH correctly classified 80% and 88%, respectively.

CONCLUSIONS

Sonographic AT characteristics are normal in non-FH dyslipidemias. Identification of suspected FH by ultrasound using sex- and age-specific AT thickness thresholds is recommended.

Pathogenesis, detection and treatment of Achilles tendon xanthomas

Tendon xanthomatosis often accompanies familial hypercholesterolaemia, but it can also occur in other pathologic states. Achilles tendons are the most common sites of tendon xanthomas. Low-density lipoprotein (LDL) derived from the circulation accumulates into tendons. The next steps leading to the formation of Achilles tendon xanthomas (ATX) are the transformation of LDL into oxidized LDL (oxLDL) and the active uptake of oxLDL by macrophages within the tendons. Although physical examination may reveal Achilles tendon xanthomas (ATX), there are several imaging methods for their detection. It is worth mentioning that ultrasonography is the method of choice in everyday clinical practice. Although several treatments for Achilles tendon xanthomas (ATX) have been proposed (LDL apheresis, statins, etc.), they target mostly in the treatment of the basic metabolic disorder of lipid metabolism, which is the main cause of these lesions. In this review we describe the formation, detection, differential diagnosis and treatment of ATX as well as the relationship between tendon xanthomas and atheroma.

Impact of chronic LDL-apheresis treatment on Achilles tendon affection in patients with severe familial hypercholesterolemia: a clinical and ultrasonographic 3-year follow-up study

OBJECTIVE

Pain of Achilles tendon (AT) is a common symptom in patients with severe familial hypercholesterolemia (FH) and often associated with AT xanthomas. It is unknown if these changes are potentially reversible during lipid lowering treatment. LDL-apheresis (LA) represents the most effective lipid lowering regimen. Aim of this investigation was to determine clinical and ultrasonographic reduction of AT xanthomas in patients with severe FH undergoing regular LA.

METHODS

At baseline, patient history of 22 patients with FH undergoing LA was obtained and their 44 ATs were evaluated clinically and with ultrasound for the presence of xanthomas. Three years later, both examinations of ATs could be repeated at follow-up visits in 16 patients. AT thickness and changes in echo structure were assessed at both points of time and compared to each other as well as to a healthy control group (n = 21). ROC analysis was performed to identify the optimal cut-off in AT thickness between healthy and affected ATs.

RESULTS

Twelve of 22 FH patients suffered from AT pain at least once during their life-time. At baseline, AT thickness was significantly increased compared to the healthy control group (mean sagittal diameter 10.1 +/- 3.6 mm). At follow-up, AT thickness was significantly reduced to 8.2 +/- 3.3 mm (mean) under LA, whereas changes in echo structure were less distinct between both visits. Conversely, in the control group, mean AT thickness was 5.2 +/- 0.6 mm. The optimal cut-off between healthy and affected ATs was determined to be 6mm.

CONCLUSIONS

Ultrasonographic changes of the AT (thickening and changes in echo structure) are frequent in patients with severe FH, even if xanthomas are not clinically evident. LA treatment has the capability to reduce AT xanthomas and thickness. Ultrasound may give information about diagnosis and follow-up of AT affection in patients with FH.

Sonography of Achilles tendon xanthomas in patients with heterozygous familial hypercholesterolemia

OBJECTIVE

Xanthomas are an essential diagnostic criteria of familial hypercholesterolemia. The objective of this study was to determine if xanthomas of the Achilles tendon can be revealed on sonography when the condition is clinically unsuspected in patients with heterozygous familial hypercholesterolemia.

SUBJECTS AND METHODS

Ninety-four patients (52 females, 42 males; 12-73 years old; mean age, 44 years) with a proven diagnosis of heterozygous familial hypercholesterolemia were studied. Achilles tendons of these patients were clinically evaluated and examined with sonography. Size and echo structure of the Achilles tendons were categorized as normal, having hypoechoic nodules (grade 1), or diffusely hypoechoic with a heterogeneous echo structure (grade 2).

RESULTS

Sixty-two patients had positive physical examination findings for Achilles tendon xanthomas. Fifty-seven (92%) of these patients had abnormally large tendons (> or =7.1 mm) on sonography. Grade 1 or grade 2 echo structure compatible with xanthomatosis was found in at least one Achilles tendon of all 62 patients. Of the 94 patients in the study group, 32 patients had negative or indeterminate physical examination findings for Achilles tendon xanthomas. Sonography showed that two (6%) of these patients had an enlarged (> or =7.1 mm) Achilles tendon. Grade 1 or grade 2 echo structure compatible with xanthomatosis was found in 26 (81%) of these 32 patients.

CONCLUSION

Sonography is significantly more sensitive than physical examination for the detection of Achilles tendon xanthomas in patients with heterozygous familial hypercholesterolemia and normal-sized Achilles tendons. Our study suggests that sonography may play an important role in the early diagnosis of heterozygous familial hypercholesterolemia.

Relation of cholesterol-year score to severity of calcific atherosclerosis and tissue deposition in homozygous familial hypercholesterolemia

The high concentrations of low-density lipoprotein cholesterol in plasma lead to accelerated atherosclerosis in patients homozygous for familial hypercholesterolemia (FH). We addressed the hypothesis that lipid deposition in the arterial vasculature and in nonvascular tissues in these patients correlates with both the duration and severity of their hypercholesterolemia. The severity of calcific atherosclerosis was defined by calcification scores and a calcified volume determined by electron beam tomography. The extent of tendinous xanthomatosis was quantitated by computed tomography. A cholesterol-year score was calculated based on the age and the yearly mean serum cholesterol concentration of each patient. Seventeen patients homozygous for FH were followed up. The average total cholesterol concentration in the study group was 780 +/- 231 mg/dl (20.2 mmol/L), and the cholesterol-year scores ranged from 2,172 mg-year/dl (56 mmol-year/L) to 32,260 mg-year/dl (834 mmol-year/L). Achilles tendon width (r=0.86) and cross-sectional area (r=0.81; both p <0.001) were best correlated with the cholesterol-year score. In addition, the coronary (r=0.61; p<0.05), ostial (r=0.45; p<0.05), and total (r= 0.77; p<0.001) calcification atherosclerosis scores all were best correlated with the cholesterol-year score. Calcific atherosclerosis was not observed in these patients until the cholesterol-year score exceeded 10,000 mg-year/dl (260 mmol-year/L). These findings establish a direct association of cholesterol-year with extravascular lipid deposition in tissues of patients with FH. The cholesterol-year score may be useful in defining the risk of atherosclerosis in patients with more common forms of hypercholesterolemia.

Anatomy of the Achilles tendon (tendo calcaneus) with respect to tendon thickness measurements

267 normal controls of different ages underwent achilles tendon thickness measurements by ultrasonography (US) for reference. 96 recruits and 10 young women additionally underwent magnetic resonance imaging of the achilles tendons and calves for more systematic evaluation of the factors influencing tendon thickness. Children under 10 had a tendon thickness (mean +/- SD) of 4.6 +/- 0.8 mm, 10-17 year-olds 6.1 +/- 0.8 mm, 18-30 year-olds 6.3 +/- 0.5 mm and over 30 year-olds 6.9 +/- 1.0 mm. Women had slightly thinner tendons than men, but the difference was statistically significant only in the oldest age group. Normal variation in shape of the tendon caused up to a 25% variation in the measured thickness values. In the large sample of recruits a statistically significant correlation was found between the tendon thickness and body height. Differences in population height could account for the measured differences in normal achilles tendon thickness found in studies on Japanese subjects compared with studies on European and American subjects.

Sonography in the detection of achilles tendon xanthomata in children with familial hypercholesterolaemia

Patients with heterozygous familial hypercholesterolaemia (FH) are at high risk for the development of coronary artery disease. Achilles tendon xanthomata are often the first clinical manifestation of FH, but are seldom palpable earlier than during the third decade. Twenty-one FH children aged 3-18 years underwent high-frequency ultrasound examination of the achilles tendon. Hypoechoic infiltration of the normal tendon structure was demonstrated in 8 of 21 (38%) of the FH children. The findings were similar in boys and girls. Control subjects (n = 68) aged 1-25 years had no sonographically detectable tendon abnormalities. The thickness of the achilles tendon of the FH children was (mean +/- SD) 7.1 +/- 1.5 mm (range 5-10 mm). The respective values for the controls were 5.8 +/- 1.0 mm (3-7 mm. We conclude that ultrasound examination sensitively detects cholesterol accumulation in the achilles tendon of FH children before tendon xanthomata are clinically evident.

Ultrasonography in the detection of Achilles tendon xanthomata in heterozygous familial hypercholesterolemia

We have examined the usefulness of ultrasound (US) in the detection of Achilles tendon (AT) xanthomata in heterozygous familial hypercholesterolemia. Our study is based on 30 adult subjects with heterozygous familial hypercholesterolemia (FH) (16 men, 14 women), 27 subjects with other non-familial forms of severe hypercholesterolemia (non-FH) with serum total cholesterol levels > or = 8 mmol/l (13 men and 14 women) and 31 subjects without marked hypercholesterolemia of the same age (control group; serum total cholesterol < 8 mmol/l) (15 men, 16 women). The three groups were comparable with respect to age, sex and body mass index. In the control group the mean sagittal thickness of AT was 4.5 mm (95% CI 3.2, 5.9 mm) and the mean coronal breadth of AT 11.0 (95% CI 9.0, 13.0 mm). Mean thickness of AT was 4.9 (range 4-7) mm in the non-FH group and 11.1 (5-16) mm in the FH group. The mean breadth of AT was in these groups 12.0 (10-17) mm and 19.2 (12-27) mm, respectively. Using the upper 95% confidence interval cut-off point in the control group as a criterion for normal AT thickness and breadth, 6 (22%) of non-FH and 29 (97%) of FH patients had increased AT thickness and 5 (19%) vs. 26 (87%) patients had increased AT breadth, respectively. The sensitivity of AT thickness for identifying FH was 0.97, specificity 0.78 and positive predictive value 0.83. The sensitivity of AT breadth in identifying FH was 0.87, specificity 0.81 and positive predictive value 0.84. None of the control subjects and none of the non-FH patients showed structural abnormalities of AT in the US, whereas 89% of FH-patients showed hypoechogenicity of AT. FH-score obtained by summing up the number of abnormal US findings gave a sensitivity of 0.93, a specificity of 0.96 and a positive predictive value of 0.96 for AT US in discriminating FH from non-FH. In conclusion, US examination of AT is a useful method in the detection of AT xanthomata and thus of help in the diagnosis of heterozygous FH.

Magnetic resonance imaging of Achilles tendon xanthomas in familial hypercholesterolemia

The demonstration of tendon xanthomas is helpful in diagnosing heterozygous familial hypercholesterolemia, but in many patients lipid may accumulate without clinical abnormality being present. We investigated the possibility of detecting the lipid element with magnetic resonance (MR) imaging in seven patients with familial hypercholesterolemia and six controls. Although the mean relative signal intensities measured on long TR/TE spin echo sequences of the tendon were significantly higher in patients than in controls, the lack of such elevation does not rule out the presence of such lesions. In vitro measurements indicated that the signal intensity of triglycerides was quenched by cholesterolesters. The anatomic findings of MR imaging were compared with those of ultrasonography (US), showing excellent correlation in measurements between MR images and US [r(S) = 0.95 and 0.97 respectively]. MR imaging and US provide equal information on the anatomy of the Achilles tendon; as an abnormally increased signal intensity within the xanthoma on MRI was found in only a minority of our patients, the value of MRI in the demonstration of Achilles tendon xanthomas is limited when using conventional T1 and T2 spin echo sequences.

[Hyperlipidemia and osteoarticular manifestations]

Hyperlipoproteinaemia, notably types II and IV, may give rise to various musculoskeletal disorders. Mono-, oligo- or polyarthritis, or even simple arthralgias, are often encountered in patients with severe type IIa hyperlipoproteinaemia, the most satisfactory tentative explanation for this being a microcrystalline pathology. Tendinitis is also frequent, particularly in children. The same manifestations have also been reported, although more occasionally, in type IV hyperlipoproteinaemia. Skeletal lesions, such as xanthoma or lipoma ossificans, are extremely rare. Other musculoskeletal disorders, including gout and aseptic osteonecrosis, are often associated with hyperlipidaemia. Some diseases may induce secondary hyperlipidaemia but have their own rheumatological manifestations. Finally, lipid-lowering drugs, such as fibrates and statines, sometimes induce disabling myalgias.