Magnetic resonance imaging of intramuscular myxoma with histological comparison and a review of the literature.

OBJECTIVE: To evaluate the magnetic resonance (MR) features of intramuscular myxoma (IM) compared with its pathological findings. DESIGN: Two radiologists retrospectively reviewed records and imaging studies of patients with histologically proven IM. Two radiologists also analyzed by consensus all the MR studies (pre- and post-contrast T1-weighted and T2-weighted sequences) and a pathologist reviewed the available histological material. PATIENTS: Seventeen patients with 18 histologically proven IM were reviewed. Histological samples of 11 of these 18 tumors were available for pathological analysis. RESULTS: There were 14 women and three men, with a mean age of 58.9 years. IM involved predominantly the thigh (n=10). MR imaging showed well-circumscribed intramuscular masses, hypointense on T1-weighted and hyperintense on T2-weighted images. Eleven masses were homogeneous and seven slightly heterogeneous due to fibrous septa. Enhanced MR imaging demonstrated three different patterns: peripheral enhancement (n=1), peripheral and patchy internal enhancement (n=7) or peripheral and linear internal enhancement (n=4). Intratumoral cysts were detected in four masses. MR imaging showed the presence of a pseudocapsule (n=12), fat around the lesion (n=16) and peritumoral edema (n=16). Histologically, all the tumors were hypocellular, hypovascular and myxoid. Peripheral areas of collagenous fibers formed a partial capsule and IM often merged into surrounding muscular fibers. More cellular tumors and those with scanty myxoid stroma tended to show a more prominent internal enhancement. CONCLUSION: IM shows several recognizable MR features which suggest its diagnosis.

Recombinant human acid alpha-glucosidase enzyme therapy for infantile glycogen storage disease type II: results of a phase I/II clinical trial.

PURPOSE: Infantile glycogen storage disease type II (GSD-II) is a fatal genetic muscle disorder caused by deficiency of acid alpha-glucosidase (GAA). The purpose of this study was to investigate the safety and efficacy of recombinant human GAA (rhGAA) enzyme therapy for this fatal disorder. METHODS: The study was designed as a phase I/II, open-label, single-dose study of rhGAA infused intravenously twice weekly in three infants with infantile GSD-II. rhGAA used in this study was purified from genetically engineered Chinese hamster ovary (CHO) cells overproducing GAA. Adverse effects and efficacy of rhGAA upon cardiac, pulmonary, neurologic, and motor functions were evaluated during 1 year of the trial period. The primary end point assessed was heart failure-free survival at 1 year of age. This was based on historical control data that virtually all patients died of cardiac failure by 1 year of age. RESULTS: The results of more than 250 infusions showed that rhGAA was generally well tolerated. Steady decreases in heart size and maintenance of normal cardiac function for more than 1 year were observed in all three infants. These infants have well passed the critical age of 1 year (currently 16, 18, and 22 months old) and continue to have normal cardiac function. Improvements of skeletal muscle functions were also noted; one patient showed marked improvement and currently has normal muscle tone and strength as well as normal neurologic and Denver developmental evaluations. Muscle biopsies confirmed that dramatic reductions in glycogen accumulation had occurred after rhGAA treatment in this patient. CONCLUSIONS: This phase I/II first study of recombinant human GAA derived from CHO cells showed that rhGAA is capable of improving cardiac and skeletal muscle functions in infantile GSD-II patients. Further study will be needed to assess the overall potential of this therapy.

Clinical Studies in Non-chromosome 4-Linked Facioscapulohumeral Muscular Dystrophy.

OBJECTIVES: To characterize clinically and molecularly a large, non-chromosome 4-linked facioscapulohumeral muscular dystrophy (FSHMD) family. METHODS: Neurological evaluations of affected (N = 55) and at-risk (N = 48) individuals were performed along with selected laboratory analyses, including creatine kinase testing, muscle biopsy, p13E-11 fragment analysis, and cytogenetic studies. Genetic analyses of the scapuloperoneal muscular dystrophy and scapuloperoneal muscular atrophy regions on chromosome 12 were performed using genetic markers flanking the intervals of interest and parametric LOD score analyses. RESULTS: Clinically, the FSHMD in individuals in this family is indistinguishable from that observed in chromosome 4-linked FSHMD. Fragment analysis with p13E-11 showed no small fragment segregating with the family and no evidence for 4:10 translocation or deletion of the p13E-11 binding site. Linkage analysis excluded the loci for autosomal-dominant scapuloperoneal muscular dystrophy and scapuloperoneal muscular atrophy. CONCLUSIONS: This family is clinically similar to patients with the chromosome 4-linked FSHMD. These data support our previous hypothesis of genetic heterogeneity within FSHMD.

Diclofenac sodium (Voltaren) reduced exercise-induced injury in human skeletal muscle.

PURPOSE: To examine the effects of prolonged systemic administration of diclofenac sodium (Voltaren), a nonsteroidal anti-inflammatory drug, on objective indices of exercise-induced muscle damage in humans. METHODS: Fifty-four volunteers (mean age, 26.4 yr; range, 18-35) participated in this randomized double-blind, placebo-controlled trial. To achieve steady-state tissue levels, either placebo or diclofenac was orally administered two times a day for 27 consecutive days. A strenuous 20-min stepping exercise program, about which the subjects were unfamiliar, was conducted on day 15. Creatine kinase (CK) activities were measured immediately before the exercise session and on days 16, 18, and 27. Vastus lateralis muscle samples were obtained immediately before exercise and on day 27 for subsequent histological characterization of muscle inflammation. RESULTS: The preexercise muscle samples revealed no difference in muscle damage between the two groups. However, the postexercise muscle samples showed that the diclofenac-treated group demonstrated less muscle tissue damage than placebo-treated subjects (P = 0.002). The administration of diclofenac also resulted in a significant lowering of post-/pre-exercise CK ratios on days 18 (P = 0.03) and 27 (P = 0.02) compared with the placebo group, an indirect finding that supports the possibility of diclofenac reducing exercise-induced muscle damage. CONCLUSION: These findings demonstrate preadministration of diclofenac (in accordance with tissue half-life pharmacokinetics) significantly reduces quantitative indices of exercise-induced skeletal muscle damage in human muscle.

Myxoid liposarcoma of the supraclavicular fossa.

Liposarcomas generally originate most often in the extremities or retroperitoneum, less frequently in the head and neck, and rarely in the thorax. We describe a particularly rare presentation of myxoid liposarcoma originating in the supraclavicular fossa. The mass was resected and has not recurred. We searched our pathology database for other soft-tissue tumors of the supraclavicular fossa and found no other case of sarcoma originating in this site. In addition, we performed a literature review of thoracic and neck liposarcomas to identify similar cases and discuss their clinical course.

Acute pancreatitis in an infant with lactic acidosis and a mutation at nucleotide 3243 in the mitochondrial DNA tRNALeu(UUR) gene.

UNLABELLED: The A to G point mutation at position 3243 of the mitochondrial DNA tRNALeu(UUR) gene is commonly found in patients with the syndrome of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS). A male patient was referred at 7 months with failure to thrive, developmental delay, microcephaly and hypotonia since age 2 months. He had developed lactic acidosis and increasingly frequent seizures since age 5 months. The patient was admitted at 15 months with pleural and pericardial effusions, which resolved. Three weeks later he developed evidence of pancreatitis with hyperglycemia, sudden profound increase in lactic acidosis and increased serum lipase. He died unexpectedly the next day of cardiorespiratory collapse following an acute gastro-intestinal hemorrhage. Analysis of mitochondrial DNA (mtDNA) in muscle showed heteroplasmy for the mutation MTTL1*MELAS3243G (> 95%). Infants with this mutation commonly present with failure to thrive, significant developmental delay, and hypotonia, while stroke-like episodes occur later in survivors. They usually have lactic acidosis and a high percentage of mutant mtDNA in muscle. CONCLUSION: Respiratory chain disorders including the mtDNA MTTL1*MELAS3243G mutation should be suspected in infants with this systemic and neurologic presentation. Pancreatic dysfunction, both acute and chronic, needs to be added to the list of symptoms of disorders of the respiratory chain.

Mitochondrial myopathy with anemia, cardiomyopathy, and lactic acidosis: a distinct late onset mitochondrial disorder.

A 40-year-old woman presented with profound muscle weakness resulting in failure to wean from a ventilator and persistent lactic acidosis after having recovered from a pneumonia complicated by adult respiratory distress syndrome, myocardial infarction, renal failure and shock. She had a 28 year history of chronic anemia and exercise intolerance. Anemia and thrombocytopenia persisted after admission. Nonobstructive hypertrophic cardiomyopathy was present. A stroke-like episode occurred. A mitochondrial myopathy with deficiencies in complexes IV and II was demonstrated, but no DNA defect has yet been found. This patient represents a distinct clinical presentation of a mitochondrial disorder characterized by late onset mitochondrial myopathy, chronic anemia, cardiomyopathy, and lactic acidosis.

The management of desmoid tumors.

PURPOSE: To determine the efficacy of different treatment modalities for desmoid tumors. MATERIALS AND METHODS: We reviewed the treatment of 40 patients with histologically confirmed desmoid tumors seen at Duke University Medical Center between 1974 and 1990. RESULTS: Radiotherapy was administered to 16 patients (Group I)--14 with recurrent disease s/p surgery and in two as initial treatment. The average size of the irradiated lesions was 9.3 +/- 3.9 X 8.4 +/- 3.5 cm. With a median follow-up of 57.5 months and a median administered dose of 5400 cGy (mean 5286 cGy, range 4960-5620 cGy), local control has been obtained in 15/16 patients (94%). Complete regression (5/16), partial regression (5/16), or stable disease (5/16) was produced in 15 patients while one patient failed and was salvaged via gross total resection. Continued regression has been seen up to 60 months after treatment. Fourteen patients underwent primary gross total resection and two underwent subtotal resection (Group II). None received post-operative radiotherapy. Three of 14 patients (21%) recurred after gross total resection. All three were salvaged with subsequent gross total resection. After subtotal resection, 2/2 patients recurred. With a mean follow-up of 52 months, 14 patients are without evidence of disease, one is dead with disease (unrelated cause of death), and one was lost to follow-up after recurrence. Eight patients have been treated with combinations of chemotherapy, NSAIDS, anti-estrogens, and immunotherapy with mixed results (Group III). A subset of seven patients with retroperitoneal disease taken from all three groups had large tumor burden (mean size 17 X 15 cm), an infiltrative nature, as well as a difficult location. The disease was surgically resectable in three patients. One is without evidence of disease 9 years after gross total resection alone. Disease has been stabilized with radiotherapy in the other two patients after multiple unsuccessful surgical resections. Of four patients with unresectable disease, two are dead of disease, one died of unrelated causes with disease, and regression of disease was obtained in the other with Gamma-interferon after unsuccessful treatment with tamoxifen and vincristine, doxorubicin, and cyclophosphamide chemotherapy. CONCLUSION: Gross total resection is the indicated initial therapy, if it can be performed without significant disfigurement. Radiotherapy is also excellent for obtaining local control, even in patients with a large burden of recurrent disease. Doses in the range of 50 to 55 Gy give a chance of local control equal to that obtained with higher doses previously reported.

Ipecac myopathy and cardiomyopathy.

Two cases of ipecac myopathy, one with associated cardiomyopathy are reported. Both patients were young women with eating disorders who came to medical attention because of diffuse muscle weakness. Clinical and electromyographic data suggested ipecac myopathy and muscle biopsies confirmed this diagnosis. One patient had associated clinical and echocardiographic evidence of significant cardiomyopathy. The myopathy resolved and the echocardiogram returned to normal after discontinuing the use of ipecac.

Micro-anastomosis of 0.3-0.4 mm vessels after cold ischemia using a rat model of toe-to-thumb transplantation.

Anastomoses of vessels of less than 0.5 mm in diameter remain a challenge from the technical aspect. Clinically such anastomoses are necessary for replantation of the distal digit in adults and whole digits in children. Survival data for replantation of these parts after prolonged ischemia have not yet been reported. Since a rat foot has an anatomic structure similar to the human hand, we used 40 rats as models of toe-to-thumb transplantation to study the survival rates of transplanted toes after various periods of cold ischemia (4 degrees C) of the amputated part. While a 100% success rate was achieved following immediate transplantation of the amputated digits (control group), the survival rates were 87.5, 75, 75, and 62.5% after transplantation of digits cooled for 24, 48, 72, and 96 hours, respectively (groups 2-5). No exact ischemic time limit was demonstrated. The results suggest that, in this model, optimal digital replantation results are achievable even after a 24 hour period of cooling preservation.

Oncocytic differentiation in intrahepatic biliary cystadenocarcinoma.

An intrahepatic biliary cystadenocarcinoma in a 56-yr-old white man was characterized by pronounced oncocytic differentiation. Grossly the tumor was a well-demarcated cyst filled with numerous branching papillary fronds. Most tumor cells had abundant granular, intensely eosinophilic cytoplasm on light microscopic examination and large numbers of densely packed mitochondria by electron microscopy. Mucin-secreting cells were also present. The patient returned 20 mo after resection of the primary tumor with recurrent tumor in the liver and widely disseminated disease throughout the abdominal cavity, and he died 5 mo later. Although less differentiated, the recurrent tumor again contained greatly increased numbers of mitochondria. The partial loss of oncocytic differentiation in the evolution of the present case and the benign nature of purely oncocytic tumors suggest that in the presence of mixed histologic features the potential for tumor progression is primarily determined by the lesser differentiated or nononcocytic component. To the best of our knowledge, oncocytic differentiation has not been previously described in biliary neoplasia.

Nasopharyngeal teratomas.

Teratomas are the most common congenital tumors, but neoplasms of the nasopharynx are rare in neonates and children. Four histologic types of nasopharyngeal teratomas occur-dermoids, teratoids, true teratomas, and epignathi-of which dermoids comprise the vast majority. A case is presented of a neonate born at term exhibiting signs of respiratory difficulty, which were found to be caused by a true teratoma of the nasopharynx. A review of several large case series of pediatric teratomas confirmed the rarity of occurrence at this site. An extensive review of case reports identified those meeting the criteria of true teratomas of the nasopharynx; the characteristics of these cases are delineated.

Adenoid cystic carcinoma of the breast metastatic to the kidney. A clinically symptomatic lesion requiring surgical management.

Adenoid cystic carcinoma (ACC) of the breast is a rare histologic type of breast cancer associated with a good prognosis. A woman who earlier had a pulmonary metastasis surgically resected 6 years postmastectomy developed clinically symptomatic bleeding from a renal metastasis 12 years postmastectomy. An atypical angiographic picture (moderate vascularization) for secondary renal neoplasms was observed. The characteristic histologic features of ACC were present in all specimens; ultrastructural characteristics of ACC were identified in the renal lesion. Successful surgical management of these metachronous solitary metastases demonstrates the therapeutic utility of aggressive management in maintaining disease control of this histologic type of breast cancer.

The effect of acute denervation on the microcirculation of skeletal muscle: rat cremaster model.

Although tissue is denervated during replantation of a severed part, tissue transfer, or muscle transplantation, there are few studies concerning the effects of acute denervation on muscle microcirculation. We have described a surgical procedure that totally denervates the rat cremaster muscle. Histological examination of the denervated tissue has given convincing evidence of nerve degeneration and skeletal muscle atrophy, accompanied by electrophysiological evidence of total denervation. The diameters of each component of the microcirculation were measured before and after denervation. Arterioles and arteries ranging in size from 10 to 70 microns in diameter were found to increase significantly in size immediately after acute denervation. Larger arteries and veins did not undergo significant diametrical increases. These findings suggest that total acute denervation significantly increases the diameter of small arteries and arterioles, thereby decreasing the resistance in the arterial bed and increasing blood flow. Since this phenomenon is of limited duration (20 min), it would appear to be ineffective in enhancing reperfusion and oxygenation at the time of reattachment of amputated parts or during vascularized tissue transfers, until methods of prolonging it for several hours or more are found.

To excite a heart: a bird's view.

Ultrastructural investigations of avian cardiac muscle, including ratite hearts, have provided great insights into the mechanisms as to how excitation leads to contraction in the heart. The geometry of the conduction fibers of ratite hearts confirms earlier observations on birds showing that the geometry of the conduction system and its component cells is adapted to hearts of different sizes and rates of contraction so as to maintain a differential in conduction velocities between the conduction system and the working fibers. The study of the ratite conduction fibers bears out the idea of an inverse relationship between the size of the gap junctions and the input resistance of cardiac cells. The anomalous extended junctional SR typical of all avian hearts, proscribes the notion of direct contact transduction into calcium release for contraction of an excitatory signal propagating at the cell surface. Couplings appear well suited to maintain direct, if transitory, connections to the extracellular space in addition to harboring channels for intracellular calcium release.

Glutathione protects cardiac and skeletal muscle from cyclophosphamide-induced toxicity.

Administration of cyclophosphamide at a dose which is lethal to 10% of control athymic nude mice resulted in sudden death within 3 h in all mice that had been pretreated with the glutathione synthesis inhibitor L-buthionine-SR-sulfoximine. In Fischer 344 rats pretreated with L-buthionine-SR-sulfoximine, the cyclophosphamide dose producing 100% acute toxicity was lowered from 500-150 mg/kg; cardiac monitoring revealed ventricular fibrillation to be the cause of death. These and additional studies reported demonstrate that cytoplasmic glutathione is an important protectant against the cardiac and skeletal muscle toxicity of cyclophosphamide and indicate that such toxicity may be substantially increased by glutathione depletion. Since diet and many drugs (including cyclophosphamide itself) are known to affect glutathione levels, the present studies suggest that cardiac and skeletal muscle glutathione content is likely to be a clinically significant determinant of the frequency and severity of the adverse drug interactions and systemic toxicity sometimes observed during cyclophosphamide therapy.