This 13-year-old patient presented with relentlessly progressive treatment refractory myoclonic epilepsy.
What are the inclusions seen in PASd stained sections of axillary skin biopsy (Figures #1 and #2).
A. Normal nucleus
C. Russell bodies
D. Lafora bodies
Correct answer: Lafora bodies
The PASd stain nicely demonstrates “polyglucosan bodies” within the cytoplasm of sweat gland cells. In the context of this patient’s clinical history these are consistent with Lafora bodies.
Lafora disease is a rare autosomal recessive disorder caused by mutations in EPM2A (laforin) and NHLRC1 (aka EPM2B; malin). Clinically it manifests as late childhood to early adolescent severe progressive myoclonus epilepsy, and it is typically fatal (usually within 10 years).
Lafora bodies are found in brain, liver, skeletal muscle, and axillary skin.
There are other neuromuscular disorders associated with “polyglucosan bodies.”
Reference(s) / additional reading:
Nitschke F, Ahonen SJ, Nitschke S, Mitra S, Minassian BA. Lafora disease – from pathogenesis to treatment strategies. Nat Rev Neurol. 2018 Oct;14(10):606-617. doi: 10.1038/s41582-018-0057-0. PMID: 30143794; PMCID: PMC6317072.
Sathiah P, Gochhait D, Dehuri P, Subramanian H. Diagnosis of Lafora Disease by Skin Biopsy. J Clin Diagn Res. 2017 Sep;11(9):EJ01-EJ02. doi: 10.7860/JCDR/2017/28570.10552. Epub 2017 Sep 1. PMID: 29207724; PMCID: PMC5713746.
Cenacchi G, Papa V, Costa R, Pegoraro V, Marozzo R, Fanin M, Angelini C. Update on polyglucosan storage diseases. Virchows Arch. 2019 Dec;475(6):671-686. doi: 10.1007/s00428-019-02633-6. Epub 2019 Jul 30. PMID: 31363843.
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