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Vacuolar Myopathy

Article
Figure 1: Frozen section hematoxylin and eosin, 400x original magnification Multiple vacuolar change toward the periphery of the muscle fiber that are variably optically clear to containing finely granular basophilic material (for example see black arrows).   This 60-year-old patient noticed slowly progressive difficulty getting into and out of their chair at work over the past year, and increased tripping and falling. Family history was negative for neuromuscular disorder.   What is your diagnosis based on Figures 1-5? A. Inclusion Body Myositis B. Mitochondrial myopathy C. Pompe disease D. Lipid storage myopathy   Figure 2: Frozen section modified Gomori Trichrome,...
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EMG Needle Site

Article
EMG Needle Site
Figure 1: Frozen section hematoxylin and eosin; 200x original magnification Note the increased cellularity within the perimysium due to the presence of foamy macrophages (large arrow). The adjacent muscle fibers show some variation in least mean diameter and a few atrophic regenerating fibers are present.   This middle-aged patient presented with a two year history of bilateral lower extremity pain and weakness predominately involving anterior thighs. Electrodiagnostic studies one month prior to muscle biopsy showed minimal myopathic features without evidence for neurogenic change. Lower extremity (3/5) and upper extremity (4/5) weakness and waddling gait were noted on physical examination.  Muscle...
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Vascular Changes On Thick Sections

Article
vasculitis
Low power image: The small arteriole (large arrow) shows thickening and hypercellularity of its wall.  The hypercellularity is in part due to the presence of chronic cells. Note the marked loss of myelinated axons in the two nerve fascicles (small arrows)   This 50-year-old patient presented with microscopic hematuria, weight loss, and difficulty with gait. Electrodiagnostic studies are reported to have demonstrated features of a multifocal sensorimotor neuropathy. Laboratory studies showed positive cANCA, elevated ESR and CRP, and normal CPK. The patient was treated with steroid and azathioprine prior to nerve biopsy.   Which of the following morphologic features in...
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Multiple Mononeuropathy

Article
Multiple mononeuropathy
This 25-year-old patient presented with clinical features of mononeuropathy multiplex (multifocal neuropathy). Serologic studies showed normal inflammatory markers. The nerve biopsy was performed to evaluate for vasculitis. The patient was treated with steroids prior to biopsy.   Based on the following images (see Figures 1 – 5) what additional testing would be most warranted? A. ANCA B. Del/Dup PMP22 C. Amyloid subtyping D. Hemoglobin A1C   Note the two axons that appear enlarged (thick arrows) compared to other myelinated axons within the nerve fascicle   Note the several axons have thicker myelin sheaths (thick arrows) compared to other large-diameter myelinated...
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Pontine Lesion

Article
Pontine Lesion, large cystic lesion filled with grumous material within the right basis pontis
  This middle-aged patient presented with left-sided upper and lower extremity weakness. MRI demonstrated a 2.5 cm cystic ring-enhancing lesion in the pons. The patient’s condition deteriorated and they expired.  An autopsy was performed.   Which of the following would best complete the following sentence based on the gross (Figure #1) and microscopic (Figures #2 and #3 ) findings?  The patient has a history of ______. A. Bacterial sepsis B. Large hilar lung mass C. Multiple sclerosis D. Eating raw pork   Answer: Large hilar lung mass Figure #1 shows large cystic lesion filled with grumous material within the right...
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Mycobacterial Infection

Article
Mycobacterial Infection
Hematoxylin and eosin FFPE 100x original magnification Hematoxylin and eosin FFPE 100x original magnification   Acid Fast Stain (Kinyoun) FFPE 1000x oil immersion   This 45-year-old patient presented to the emergency department with left thigh and buttock pain of four months’ duration, and two weeks of fever (105oF) and chills. The patient's past medical history is significant for autoantibody-positive rheumatoid arthritis treated with mycophenolate mofetil and steroid, and recent findings of focal central disc herniation at L5-S1. The patient is reported to have traveled to Asia and India. Chest X-ray showed mild bibasilar atelectasis. MRI showed avascular necrosis of the...
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Vasculitis

Article
ANCA-Associated Vasculitis, anti-neutrophil-cytoplasmic antibodies (ANCA) testing
Hematoxylin and eosin; 200x and 400x original magnifications   This 60-year-old patient presented with fevers and bilateral leg myalgias of one month’s duration. Laboratory studies demonstrate elevated ESR (120) and normal CPK. On physical examination, the patient had pain upon palpation of both calf muscles. Muscle biopsy was performed. Given the clinical history and features seen in the image, what additional laboratory test results would be best to request? A. ANCA B. Stool ova and parasites C. C-reactive protein D. RPR   Answer: ANCA The image shows the circumferential presence of mononuclear histiocytes within the wall of a small artery...
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Node of Ranvier

Article
Node of Ranvier, Neuro Notes, neuropathology
The patient is a 70-year-old male with recent bilateral foot drop. Laboratory studies showed normal/negative pANCA, cANCA, and MPO. His symptoms partially responded to treatment with prednisone. Nerve biopsy was performed to evaluate for vasculitis. What is the structure indicated by the arrow in the image? A. Internode B. Myelin incisure C. Traction artifact D. Node of Ranvier   Answer: Node of Ranvier Peripheral nerve “nodes of Ranvier” are small gaps between adjacent segments of myelin sheath formed by individual Schwann cells. The specialized regions are rich in voltage-gated sodium ion channels and act as “booster stations” for the rapid...
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Intrafusal Muscle Fibers Muscle Fiber Spindle

Article
intrafusal muscle fibers in the muscle fiber spindle
  The intrafusal muscle fibers also serve which of the following purposes? A. Force generation B. Maintain spindle tension C. Protein storage D. Protect nerves   Answer: Maintain spindle tension The intrafusal muscle fibers are innervated by gamma and beta motor neurons and contract or relax to maintain the sensitivity of the spindle. For example when the quadriceps muscle contracts and becomes shorter, the intrafusal muscle fibers take up slack in the spindle to maintain its sensitivity to stretch. The intrafusal muscle fibers do not contribute significantly to the force of the muscle contraction, store significant protein, or protect nerves....
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Muscle Fiber Spindle

Article
Muscle fiber spindle, nerve fibers
Toluidine blue-stained thick section prepared from glutaraldehyde-fixed EPON embedded tissue (400x original magnification) What of the following single choices regarding this structure is false? A. Generates contraction B. Senses muscle stretch C. Common in muscle D. Part of myotatic reflex   Answer: Generates contraction The muscle fiber spindle detects length and rate of muscle stretch, is the most frequently found sense organ in skeletal muscle, and is part of the deep tendon reflex (monosynaptic stretch reflex/myotatic reflex). It does not contribute significantly to the force of muscle contraction. References Banks RW. The innervation of the muscle spindle: a personal history....
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Arkana
Announcement

Posted November 22nd 2021
In observance of Thanksgiving, our office will be closed Thursday, November 25th.