Toluidine Blue Stained Thick Section
This 75-year-old patient presented with complaints of numbness, tingling and burning sensation involving his right lower extremity below the level of the knee (stocking-like distribution) and foot drop. The patient’s past medical history is significant for coronary artery disease, impaired fasting glucose, peripheral neuropathy, and hypertension.
In addition to diffuse thickening of the perineurium seen in Figure #1, what abnormality is seen in Figures #2 – #4?
The toluidine blue stained thick sections show the focal presence of microfascicles. Microfascicles are comprised of unmyelinated or myelinated axons surrounded by a layer(s) of fibroblasts and perineurial cells, and represent a disorganized healing response. They are seen in the setting of peripheral nerve injury (disruption of the perineurium) following surgery (traumatic or amputation neuroma), but may also be seen in the context of nerve injury related to vasculitis, diabetic vasculopathy, and perineuritis (for example leprosy).
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