The role of striated muscle Pik3r1 in glucose and protein metabolism following chronic glucocorticoid exposure.

Chronic glucocorticoid exposure causes insulin resistance and muscle atrophy in skeletal muscle. We previously identified phosphoinositide-3-kinase regulatory subunit 1 (Pik3r1) as a primary target gene of skeletal muscle glucocorticoid receptors involved in the glucocorticoid-mediated suppression of insulin action. However, the in vivo functions of Pik3r1 remain unclear. Here, we generated striated muscle-specific Pik3r1 knockout (MKO) mice and treated them with a dexamethasone (DEX), a synthetic glucocorticoid. Treating wildtype (WT) mice with DEX attenuated insulin activated Akt activity in liver, epididymal white adipose tissue, and gastrocnemius (GA) muscle. This DEX effect was diminished in GA muscle of MKO mice, therefore, resulting in improved glucose and insulin tolerance in DEX-treated MKO mice. Stable isotope labeling techniques revealed that in WT mice, DEX treatment decreased protein fractional synthesis rates in GA muscle. Furthermore, histology showed that in WT mice, DEX treatment reduced GA myotube diameters. In MKO mice, myotube diameters were smaller than in WT mice, and there were more fast oxidative fibers. Importantly, DEX failed to further reduce myotube diameters. Pik3r1 knockout also decreased basal protein synthesis rate (likely caused by lower 4E-BP1 phosphorylation at Thr37/Thr46) and curbed the ability of DEX to attenuate protein synthesis rate. Finally, the ability of DEX to inhibit eIF2α phosphorylation and insulin-induced 4E-BP1 phosphorylation was reduced in MKO mice. Taken together, these results demonstrate the role of Pik3r1 in glucocorticoid-mediated effects on glucose and protein metabolism in skeletal muscle.

Smooth muscle hamartoma and striated muscle hamartoma: Clinicopathologic characterization of two rare entities and literature review.

Smooth muscle hamartoma (SMH) and striated muscle hamartoma (STH) are anomalous proliferations of smooth muscle or striated muscle, respectively, in anatomic sites where these tissues are normally present. To date, only limited cases have been reported describing these lesions. In this study, we sought to characterize the clinicopathologic features of both SMH and STH. A total of 27 cases of SMH and 12 cases of STH from 1990 to 2020 were identified. SMH cases had a slight male predominance (63%) and a mean age of presentation of 20 years (range: 4 months-91 years), with a mean size of 9.3 mm (±13.3). In contrast, STH were equally distributed in gender, with a mean age of presentation of 40 years (range: 3 months-66 years) and a mean size of 5.7 mm (±3.6). SMH were more commonly located in the torso and extremities (70%) and STH in the head and neck area (92%). One case of SMH recurred after 1.1 years and in the initial diagnosis the lesion was present at the tissue edge. None of the cases of STH had a recurrence. We present the largest cohort of SMH and STH, and report the first case of a recurrent SMH, suggesting the importance of obtaining a clean margin for these lesions.

Schistosoma mansoni granulomas in the skeletal striated muscles in the murine model of neuroschistosomiasis: histological findings.

Schistosomiasis mansoni presents many clinical manifestations during migration of schistosomes in their hosts, including diarrhea, hepatomegaly, splenomegaly, liver abscesses, skinlesions, brain tumors and myeloradiculopathy. No lesions have been reported in skeletal striated muscles due to schistosomiasis mansoni in the literature. This short communication reports the histopathological findings on skeletal musculature in a murine model of neuroeschistosomiasis mansoni. Lesions were found in the tongue, masseter muscle, buccinator muscle, digastric muscle and temporalis muscle. Worm recovery was carried out to confirm the infection. We describe here, for the first time in the literature, injuries in the skeletal musculature due to Schistosoma mansoni nfection.

Schistosoma mansoni granulomas in the skeletal striated muscles in the murine model of neuroschistosomiasis: histological findings

Schistosomiasis mansoni presents many clinical manifestations during migration of schistosomes in their hosts, including diarrhea, hepatomegaly, splenomegaly, liver abscesses, skinlesions, brain tumors and myeloradiculopathy. No lesions have been reported in skeletal striated muscles due to schistosomiasis mansoni in the literature. This short communication reports the histopathological findings on skeletal musculature in a murine model of neuroeschistosomiasis mansoni. Lesions were found in the tongue, masseter muscle, buccinator muscle, digastric muscle and temporalis muscle. Worm recovery was carried out to confirm the infection. We describe here, for the first time in the literature, injuries in the skeletal musculature due to Schistosoma mansoni nfection.

A Case of Feline T-cell Lymphoma with Tropism for Striated Muscle and Peripheral Nerve.

An 11-year-old female American shorthair cat was presented with a 3-month history of hindlimb ataxia and knuckling of the left forelimb. Clinical abnormalities included weight loss, hyperaesthesia of the neck and back, cardiac murmur and systemic muscle atrophy. The cat died 10 days after the initial presentation and a necropsy examination was performed. Grossly, extensive pale lesions were seen in the wall of the left ventricle and the septum of the heart. There were no detectable masses in the heart, skeletal muscles or peripheral nerves. Histopathological examination revealed diffuse, extensive infiltration of atypical lymphoid cells in the heart; the cardiac muscles were markedly degenerate and atrophic and were replaced by the neoplastic cells. Neoplastic cells with similar morphology were seen in all specimens of the skeletal muscles and peripheral nerves. Clonality analysis of the paraffin wax-embedded heart tissue revealed a monoclonal rearrangement of the gene encoding the T-cell receptor γ chain. Based on these findings, the case was diagnosed as T-cell lymphoma with tropism for striated muscle and peripheral nerve.

Ninjurin1 regulates striated muscle growth and differentiation.

Chronic pressure overload due to aortic valve stenosis leads to pathological cardiac hypertrophy and heart failure. Hypertrophy is accompanied by an increase in myocyte surface area, which requires a proportional increase in the number of cell-cell and cell-matrix contacts to withstand enhanced workload. In a proteomic analysis we identified nerve injury-induced protein 1 (Ninjurin1), a 16kDa transmembrane cell-surface protein involved in cell adhesion and nerve repair, to be increased in hypertrophic hearts from patients with aortic stenosis. We hypothesised that Ninjurin1 is involved in myocyte hypertrophy. We analyzed cardiac biopsies from aortic-stenosis patients and control patients undergoing elective heart surgery. We studied cardiac hypertrophy in mice after transverse aortic constriction and angiotensin II infusions, and performed mechanistic analyses in cultured myocytes. We assessed the physiological role of ninjurin1 in zebrafish during heart and skeletal muscle development. Ninjurin1 was increased in hearts of aortic stenosis patients, compared to controls, as well as in hearts from mice with cardiac hypertrophy. Besides the 16kDa Ninjurin1 (Ninjurin1-16) we detected a 24kDa variant of Ninjurin1 (Ninjurin1-24), which was predominantly expressed during myocyte hypertrophy. We disclosed that the higher molecular weight of Ninjurin1-24 was caused by N-glycosylation. Ninjurin1-16 was contained in the cytoplasm of myocytes where it colocalized with stress-fibers. In contrast, Ninjurin1-24 was localized at myocyte membranes. Gain and loss-of-function experiments showed that Ninjurin1-24 plays a role in myocyte hypertrophy and myogenic differentiation in vitro. Reduced levels of ninjurin1 impaired cardiac and skeletal muscle development in zebrafish. We conclude that Ninjurin1 contributes to myocyte growth and differentiation, and that these effects are mainly mediated by N-glycosylated Ninjurin1-24.

Development of Novel Micro-dystrophins with Enhanced Functionality.

Gene therapies using adeno-associated viral (AAV) vectors have advanced into clinical trials for several diseases, including Duchenne muscular dystrophy (DMD). A limitation of AAV is the carrying capacity (∼5 kb) available for genes and regulatory cassettes (RCs). These size constraints are problematic for the 2.2-Mb dystrophin gene. We previously designed a variety of miniaturized micro-dystrophins (µDys) that displayed significant, albeit incomplete, function in striated muscles. To develop µDys proteins with improved performance, we explored structural modifications of the dystrophin central rod domain. Eight µDys variants were studied that carried unique combinations of between four and six of the 24 spectrin-like repeats present in the full-length protein, as well as various hinge domains. Expression of µDys was regulated by a strong but compact muscle-restricted RC (CK8e) or by the ubiquitously active cytomegalovirus (CMV) RC. Vectors were evaluated by intramuscular injection and systemic delivery to dystrophic mdx4cv mice, followed by analysis of skeletal muscle pathophysiology. Two µDys designs were identified that led to increased force generation compared with previous µDys while also localizing neuronal nitric oxide synthase to the sarcolemma. An AAV vector expressing the smaller of these (µDys5) from the CK8e RC is currently being evaluated in a DMD clinical trial.

English Translation of M. Bérard: Tumeur Embryonnaire Du Muscle Strié. [Embryonal Tumor of Striated Muscle]. Lyon Med 1894; 77: 52.

We have chosen to translate what we believe to be the first publication of a well-documented case of a young patient with embryonal rhabdomyosarcoma. The author, M. Léon Bérard, was a hospital fellow working in the department of M. Vincent at the Charité Hospital. The document was presented to La Société des Sciences médicales de Lyon (The Society of Medical Sciences of Lyon, France), in July,1894. The translation follows below.

Relationship of DNA methylation to mutational changes and transcriptional organization in fusion-positive and fusion-negative rhabdomyosarcoma.

Our previous study of DNA methylation in the pediatric soft tissue tumor rhabdomyosarcoma (RMS) demonstrated that fusion-positive (FP) and fusion-negative (FN) RMS tumors exhibit distinct DNA methylation patterns. To further examine the significance of DNA methylation differences in RMS, we investigated genome-wide DNA methylation profiles in discovery and validation cohorts. Unsupervised analysis of DNA methylation data identified novel distinct subsets associated with the specific fusion subtype in FP RMS and with RAS mutation status in FN RMS. Furthermore, the methylation pattern in normal muscle is most similar to the FN subset with wild-type RAS mutation status. Several biologically relevant genes were identified with methylation and expression differences between the two fusion subtypes of FP RMS or between the RAS wild-type and mutant subsets of FN RMS. Genomic localization studies showed that promoter and intergenic regions were hypomethylated and the 3' untranslated regions were hypermethylated in FP compared to FN tumors. There was also a significant difference in the distribution of PAX3-FOXO1 binding sites between genes with and without differential methylation. Moreover, genes with PAX3-FOXO1 binding sites and promoter hypomethylation exhibited the highest frequency of overexpression in FP tumors. Finally, a comparison of RMS model systems revealed that patient-derived xenografts most closely recapitulate the DNA methylation patterns found in human RMS tumors compared to cell lines and cell line-derived xenografts. In conclusion, these findings highlight the interaction of epigenetic changes with mutational alterations and transcriptional organization in RMS tumors, and contribute to improved molecular categorization of these tumors.

Intraoral manifestation of systemic AL amyloidosis with unique microscopic presentation of intracellular amyloid deposition in striated muscles.

We report the history of a 59-year old patient with systemic AL amyloidosis of intraoral manifestation. The patient first presented with complaints about dysphagia and remarkable enlargement of the tongue with highly reduced mobility, as well as bilateral submucosal thickenings on the cheeks. Histopathological examination of the incisional biopsy of the buccal mucosa and underlying tissues revealed AL amyloidosis. The microscopic presentation was, however, unique, as the amyloid deposits were present intracellularly in the striated muscles. The subsequent bone marrow biopsy confirmed the diagnosis of primary amyloidosis/multiple myeloma - associated amyloidosis.

Striated muscle gene therapy for the treatment of lipoprotein lipase deficiency.

Excessive circulating triglycerides due to reduction or loss of lipoprotein lipase activity contribute to hypertriglyceridemia and increased risk for pancreatitis. The only gene therapy treatment for lipoprotein lipase deficiency decreases pancreatitis but minimally reduces hypertriglyceridemia. Synthesized in multiple tissues including striated muscle and adipose tissue, lipoprotein lipase is trafficked to blood vessel endothelial cells where it is anchored at the plasma membrane and hydrolyzes triglycerides into free fatty acids. We conditionally knocked out lipoprotein lipase in differentiated striated muscle tissue lowering striated muscle lipoprotein lipase activity causing hypertriglyceridemia. We then crossed lipoprotein lipase striated muscle knockout mice with mice possessing a conditional avian retroviral receptor gene and injected mice with either a human lipoprotein lipase retrovirus or an mCherry control retrovirus. Post-heparin plasma lipoprotein lipase activity increased for three weeks following human lipoprotein lipase retroviral infection compared to mCherry infected mice. Human lipoprotein lipase infected mice had significantly lower blood triglycerides compared to mCherry controls and were comparable to wild-type blood triglyceride levels. Thus, targeted delivery of human lipoprotein lipase into striated muscle tissue identifies a potential therapeutic target for lipoprotein lipase deficiency.

Analysis of ischemic muscle in patients with peripheral artery disease using X-ray spectroscopy.

BACKGROUND: Peripheral artery disease (PAD) is a vascular disease caused by atherosclerosis, resulting in decreased blood flow to the lower extremities. The ankle-brachial index (ABI) is a standard PAD diagnostic test but only identifies reduced blood flow based on blood pressure differences. The early signs of PAD manifest themselves not only at a clinical level but also at an elemental and biochemical level. However, the biochemical and elemental alterations to PAD muscle are not well understood. The objective of this study was to compare fundamental changes in intracellular elemental compositions between control, claudicating, and critical limb ischemia muscle tissue. MATERIALS AND METHODS: Gastrocnemius biopsies from three subjects including one control (ABI ≥ 0.9), one claudicating (0.4 ≤ ABI < 0.9), and one critical limb ischemia patient (ABI < 0.4) were evaluated using a scanning electron microscope and energy dispersive X-ray spectroscopy to quantify differences in elemental compositions. Spectra were collected for five myofibers per specimen. An analysis of variance was performed to identify significant differences in muscle elemental compositions. RESULTS: This study revealed that intracellular magnesium and calcium were lower in PAD compared with control myofibers, whereas sulfur was higher. Magnesium and calcium are antagonistic, meaning, if magnesium concentrations go down calcium concentrations should go up. However, our findings do not support this antagonism in PAD. Our analysis found decreases in sodium and potassium, in PAD myofibers. CONCLUSIONS: These findings may provide insight into the pathologic mechanisms that may operate in ischemic muscle and aid in the development of specialized preventive and rehabilitative treatment plans for PAD patients.

Spontaneous Regression of a Plaque-Type Striated Muscle Hamartoma.

Striated muscle hamartoma (SMH) is a rare, congenital or acquired, benign tumor that predominantly affects children. Therapeutic management has classically been surgical intervention. We present a pediatric case of a facial plaque-type SMH with spontaneous regression that highlights the importance of clinical observation for a conservative approach.

Histomorphologic and ultrastructural recovery of myopathy in rats treated with low-level laser therapy.

The purpose of the present work was to study the effect of low-level laser therapy (LLLT): helium-neon (He-Ne) and gallium arsenide (Ga-As) laser on the histomorphology of muscle and mitochondria in experimental myopathy in rats. Thirty Suquía strain female rats were distributed in groups: (A) control (intact), (B) injured, (C) injured and treated with He-Ne laser, (D) injured and treated with Ga-As laser, (E) irradiated with He-Ne laser on the non-injured muscle, and (F) irradiated with Ga-As laser on the non-injured muscle. Myopathy was induced by injecting 0.05 mg/rat/day of adrenaline in the left gastrocnemius muscle at the same point on five consecutive days, in groups B, C, and D. LLLT was applied with 9.5 J cm-2 daily for seven consecutive days in groups C, D, E, and F. The muscles were examined with optic and electronic microscopy. The inflammation was classified as absent, mild, and intense and the degree of mitochondrial alteration was graded I, II, III, and IV. Categorical data were statistically analyzed by Chi-square and the Fisher-Irwin Bilateral test, setting significant difference at p < 0.05. The damage found in muscle and mitochondria histomorphology in animals with induced myopathy (B) was intense or severe inflammation with grade III or IV of mitochondrial alteration. They underwent significant regression (p < 0.001) compared with the groups treated with He-Ne (C) and Ga-As (D) laser, in which mild or moderate inflammation was seen and mitochondrial alteration grades I and II, recovering normal myofibrillar architecture. No differences were found between the effects caused by the two lasers, or between groups A, E, and F. Group A was found to be different from B, C, and D (p < 0.001). LLLT in experimental myopathy caused significant muscular and mitochondrial morphologic recovery.

Supraphysiological levels of GDF11 induce striated muscle atrophy.

Growth and differentiation factor (GDF) 11 is a member of the transforming growth factor ß superfamily recently identified as a potential therapeutic for age-related cardiac and skeletal muscle decrements, despite high homology to myostatin (Mstn), a potent negative regulator of muscle mass. Though several reports have refuted these data, the in vivo effects of GDF11 on skeletal muscle mass have not been addressed. Using in vitro myoblast culture assays, we first demonstrate that GDF11 and Mstn have similar activities/potencies on activating p-SMAD2/3 and induce comparable levels of differentiated myotube atrophy. We further demonstrate that adeno-associated virus-mediated systemic overexpression of GDF11 in C57BL/6 mice results in substantial atrophy of skeletal and cardiac muscle, inducing a cachexic phenotype not seen in mice expressing similar levels of Mstn. Greater cardiac expression of Tgfbr1 may explain this GDF11-specific cardiac phenotype. These data indicate that bioactive GDF11 at supraphysiological levels cause wasting of both skeletal and cardiac muscle. Rather than a therapeutic agent, GDF11 should be viewed as a potential deleterious biomarker in muscle wasting diseases.

Striated Muscle in Radical Prostatectomy Specimens: A Marker of Apical Dissection Quality and an Independent Predictor of Urinary Continence after Endoscopic Extraperitoneal Radical Prostatectomy.

INTRODUCTION: The study aimed to determine if the presence and amount of striated muscle on the apical sections of the cruciate sections of laparoscopic radical prostatectomy (LRP) specimens predict early and long-term urinary continence outcomes. PATIENTS AND METHODS: We conducted a retrospective review of our prospectively collected single surgeon LRP database. We identified patients based on their continence outcomes (continent (0 pads) or incontinent at 12 months), with an approximate even spread early continent and incontinent patients). An uropathologist separate from the urology team was blinded to outcome and assessed each patients' apical cruciate sections (H&E stained) for the presence, percentage and maximal diameter of muscle and extraprostatic tissue on these sections. Specifically 2 scoring systems were used: (1) semi-quantitative estimation of percentage of muscle on the apical cruciate sections (low <5% and high >5%) and (2) percentage of total extraprostatic tissue on cruciate section (low <10% and high >10%). Logistic regression and classification and regression tree analyses were performed to identify the predictors of urinary incontinence (UI). RESULTS: In total 80 patients were analyzed, 38 were continent and 42 were incontinent at 12 months follow-up. The percentage of extraprostatic tissue/muscle being an independent predictor of being wet at 12 months (p = 0.002) on multivariate regression along with age (p = 0.04). Using percentage of extraprostatic tissue in cruciate section (high >10%) to predict UI at 12 months, it yielded 71% sensitivity, 82% specificity, 81% PPV, 72% NPV and 76% accuracy. CONCLUSION: The use of simple additional reporting of muscle and extraprostatic tissue on the apical sections of RP specimens can help to better predict the likelihood of continence return.

Effect of myogenic stem cells on the integrity and histomorphology of repaired transected external anal sphincter.

INTRODUCTION AND HYPOTHESIS: The objective was to evaluate the effect of myogenic stem cells on histological properties and the volume of striated muscle of the external anal sphincter after transection and repair. METHODS: Histological analysis was performed on the external anal sphincters of 40 young female rats euthanized at 7 or 90 days after transection and repair and randomization to injection of either phosphate buffered solution (PBS) or myogenic stem cells (SC) at the transection site. Sphincter complexes, previously evaluated for neurophysiological function, were processed for histology and analyzed for possible disruption, amount of inflammation, and volume of striated muscle. The relationship between the muscular disruption and contractile force of sphincters was evaluated. RESULTS: Disruption was seen in 100 % of sphincters 7 days after repair for both SC and control animals. Eighty-nine percent of controls and 78% of SC-administered animals had intact sphincters at 90 days. Significant inflammatory infiltrate was seen in repaired anal sphincters for both the PBS and the SC groups at 7 days, and persisted at 90 days, with no difference between treatment groups. Striated muscle volume increased from 7 to 90 days for both control and SC-administered animals. Although there was no difference in volume between treatments, there was substantial temporal improvement in contractile force generation of the sphincters receiving SC compared with those receiving PBS. CONCLUSION: In this animal model, administration of myogenic stem cells to transected/repaired anal sphincters did not alter the amount of inflammation nor the volume of striated muscle, suggesting that stem cells might improve contractile function through other cellular processes.

Rhabdomyomatous mesenchymal hamartoma presenting as a big subcutaneous mass on the neck: a case report.

INTRODUCTION: We describe the location, size, histopathologic aspect and immunohistochemical expression of a rhabdomyomatous mesenchymal hamartoma, with the aim of providing useful information for its correct diagnosis. CASE PRESENTATION: A 31-year-old Chinese man first presented 2 years previously with a solitary subcutaneous mass on the left side of his neck and under his mastoid process; the mass's size was 2 × 2 cm. The mass increased in the size in the past 2 years. Magnetic resonance imaging revealed a dumbbell shaped and well-outlined highly reflective mass, with its upperpart infiltrating the interspace of the atlanto-occipital joint. The mass was surgically removed. On macroscopic examination, the mass was oblong and partly encapsulated, the size of the mass was 4.9 × 3.5 × 3 cm, and its cut side was grey. On histologic examination, it showed a disordered collection of bundles of mature striated muscle fibres arranged in a haphazard manner and interspersed with adipose tissue, fibrocytes or mesenchymocytes and collagen, and had a myxoid matrix. On immunochemical examination, mature striated muscle was positive for desmin and myoglobin, adipose tissue and nerves were positive for S-100 protein, and fibrocytes or mesenchymocytes and collagen were positive for vimentin and cluster of differentiation 34. A diagnosis of rhabdomyomatous mesenchymal hamartoma was established. CONCLUSIONS: Rhabdomyomatous mesenchymal hamartoma is a rare dermal or subcutaneous lesion, and we describe its immunohistochemical expression for the first time. This case report provides more information on the microscopic appearance and immunohistochemical expression.

Dermatomyositis: analysis of 109 patients surveyed at the Hospital das Clínicas (HCFMUSP), São Paulo, Brazil.

BACKGROUND: Dermatomyositis affects striated muscles, skin and other organs. OBJECTIVE: To characterize the disease from January 1992 to December 2002, assessing its classification, cutaneous and systemic manifestations, and also laboratory results, therapeutic and prognostic findings compared to those in the literature. METHODS: Data were obtained from medical records of 109 patients who were classified into five groups: 23 juvenile dermatomyositis; 59 primary idiopathic dermatomyositis; 6 amyopathic dermatomyositis; 7 dermatomyositis associated with neoplasms and 14 dermatomyositis associated with other connective tissue diseases. RESULTS: Sixty patients were classified as "definite" diagnosis; 33 as "possible"; four as "probable" and 12 and as amyopathic. The average age at diagnosis was 36 years. Cutaneous manifestations occurred in all patients; the most frequent symptom was loss of proximal muscle strength; the most common pulmonary disorder was interstitial lung disease, and gastritis was the most prevalent digestive manifestation. Tumors were documented in 6.42% of cases. Lactate dehydrogenase was the muscle enzyme most frequently elevated in the majority of cases. Skin biopsies were performed in 68 patients; muscle biopsies in 53; and electroneuromyographies in 58 patients. The most commonly used treatment was corticotherapy and the mortality rate was 14.7%. CONCLUSION: in this sample, the disease appeared in younger individuals, was more frequent in women and the association with cancer was small.

Dermatomyositis: analysis of 109 patients surveyed at the Hospital das Clínicas (HCFMUSP), São Paulo, Brazil

BACKGROUND: Dermatomyositis affects striated muscles, skin and other organs. OBJECTIVE: To characterize the disease from January 1992 to December 2002, assessing its classification, cutaneous and systemic manifestations, and also laboratory results, therapeutic and prognostic findings compared to those in the literature. METHODS: Data were obtained from medical records of 109 patients who were classified into five groups: 23 juvenile dermatomyositis; 59 primary idiopathic dermatomyositis; 6 amyopathic dermatomyositis; 7 dermatomyositis associated with neoplasms and 14 dermatomyositis associated with other connective tissue diseases. RESULTS: Sixty patients were classified as "definite" diagnosis; 33 as "possible"; four as "probable" and 12 and as amyopathic. The average age at diagnosis was 36 years. Cutaneous manifestations occurred in all patients; the most frequent symptom was loss of proximal muscle strength; the most common pulmonary disorder was interstitial lung disease, and gastritis was the most prevalent digestive manifestation. Tumors were documented in 6.42% of cases. Lactate dehydrogenase was the muscle enzyme most frequently elevated in the majority of cases. Skin biopsies were performed in 68 patients; muscle biopsies in 53; and electroneuromyographies in 58 patients. The most commonly used treatment was corticotherapy and the mortality rate was 14.7%. CONCLUSION: in this sample, the disease appeared in younger individuals, was more frequent in women and the association with cancer was small. .