Diagnosis of myopathies using histology, histochemistry, immunohistochemistry and electron microscopy: a single center experience

Skeletal muscle biopsy is important for the diagnosis of motor unit disorders, systemic diseases and metabolic disorders. In some cases, routine histopathologic methods are not conclusive and histochemistry, immunohistochemistry and even an electron microscopic study are required. In this study, we describe our experience in the diagnosis of myopathies, considering all of the above-mentioned methods. During a period of 18 months, 43 specimens of patients with the impression of myopathy were submitted to the Pathology Department and were evaluated with H and E and histochemical stainings [PAS, Oil red O, ATPase, NADH-TR, Gomori Trichrome], immunohistochemistry [IHC] for dystrophin and electron microscopy. Three specimens were excluded from the study because there were only adipose tissues and no adequate muscle was present for evaluation. Twenty three [57.5%] males and 17 [42.5%] females with a mean age of 34 years were evaluated. The results were as follows: Becker's muscular dystrophy [5 cases, 12.5%], Duchenne's muscular dystrophy [3 cases, 7.5%], fascioscapulohumeral dystrophy [3 cases, 7.5%], limb girdle dystrophy [2 cases, 5%], polymyositis [6 cases, 15%], dermatomyositis [2 cases 5%], McArdle's disease [1 case, 2.5%], hypothyroidism myopathy [1 case, 2.5%], type 2 atrophy secondary to drugs and systemic diseases [2 cases 12.5%], congenital myopathy [2 cases 5%], McArdle [1 case 2.5%], unclassified myopathy [2 cases, 5%], and normal muscle biopsy [8 cases, 20%]. Although a genetic study was not available to confirm the diagnosis of cases such as fascioscapulohumeral myopathy, the diagnosis was made after putting all of the findings together including clinical presentation, family history, NCV, EMG, etc. In the cases with no definite diagnosis by the histology, histochemistry and IHC, we should perform an EM study to find out the distinct ultra-structural changes which can be diagnostic for some muscle disorders. EM study in conjunction with light microscopy of muscle biopsy could be very helpful in establishing the diagnosis of some types of myopathies

Breast metastatic alveolar rhabdomyosarcoma: FNA findings

A 25-year-old woman, a known case of vulvar rhabdomyosarcoma presented with bilateral breast nodules. Fine needle aspiration was performed. The smears revealed numerous round malignant cells, positive for malignancy. Histopathologic and immunocytochemical examination confirmed the diagnosis of metastatic alveolar rhabdomyosarcoma. The cytological findings of alveolar rhabdomyosarcoma of the breast are rarely reported. The clinical history and immunocytochemical study contributed to the diagnosis of metastatic alveolar rhabdomyosarcoma

[Comparison between light and electron microscopic findings in 30 patients with lupus nephritis]

The kidney biopsy specimen is used for initial diagnosis of patients with SLE who at the time of biopsy lack either diagnostic clinical manifestation and or serological markers. Another role is evaluation of renal dysfunction in transplanted patients when lupus has occurred in renal allograft. The aim of this study is correlating the findings of light, immunofluorescent and electron microscopy in thirty patients with lupus nephritis. The kidney biopsies of thirty patients with SLE were studied for purpose of correlating the findings of light, immunofluorescent and electron microscopy. We studied 30 parameters in light microscopy sections, 5 parameters in semi -thin and EM sections, and IgG, IgM, IgA, C3, C4 and fibrinogen in different structures of specimens by immunofluroscent microscopy. The P value and measurement of agreement of kappa was calculated. In 25 cases LM and EM correlated completely including lupus nephritis class, activity and chronicity indices and presence or absence of immune complex deposition. In 5 cases discrepancy between Light Microscopy and Electron Microscopy diagnosis was found. Three cases were classified as class three according to LM and class two by EM. LM reevaluation of all three cases showed focal and segmental endocapillary cell proliferation with neutrophilic infiltration. We found that LM study is cornerstone in the focal lesions because of the limited inclusion of glomeruli in EM. One case of class four by LM, in EM shows massive [grade three] sub-epithelial depositions and grade one sub endothelial deposition and was classified it as Class five + six. In LM, findings cellular crescent in six glomeruli, severe endocapillary cell proliferation with activity index of [16/24] were detected. So the correct diagnosis was Class five + six. The last case classified as four in LM classification and revealed moderate mesangial cell proliferation with obliteration of lumens. In EM, we had three glomeruli which all showed mesangial cell proliferation, grade two mesangial deposition, with one focus of small [grade one] sub endothelial deposition. According to the above-mentioned findings the EM class of patient was class two. We found that there is agreement between EM and semi-thin sections for detection of exact site of depositions as well as their grading. Study of semi-thin sections by LM can demonstrate the deposits that are observed on EM

Histopathologic changes of extraocular muscle fibers after injection of botulinum toxin

Use of botulinum toxin is becoming a popular way in treatment of some forms of strabismus. To evaluate the morphological changes in the orbital surface layer muscles of the rabbit eye following a single injection of botulinum toxin. 10 white Dutch rabbits weighing 2-3 kg received either 10 units [group 1; n=5] or 20 units [group 2; n=5] of botulinum toxin into the superior rectus muscle of right eye. The superior rectus muscle of the left eye in each rabbit was considered as control. The diameter of at least 20 muscle fibers of the orbital layer of the superior rectus muscle was measured with an ocular micrometer on histological sections after extirpation 2 and 1 0 days, and 4, 8 and 1 2 weeks after the injection. Marked decrease in size of muscle fibers was observed, especially on 2 and 10 days post-injection. It was more sever in animals which received 20 units of the toxin. In both groups, between 4 and 12 weeks after injection, the size of some fibers returned back to normal; rarely, the fibers became hypertrophic while atrophic changes were still present. Hypertrophy of neuro-muscular end-plate was seen accompanied with atrophic changes. Fibrosis around the muscle fibers was rarely seen. Injection of botulinum toxin into extraocular muscles causes atrophic changes which seems to be more severe with higher doses. The effect of botulinum toxin has been persisted up to 8 weeks