Charcot–Leyden crystals: do they exist in veterinary species? A case report and literature review

Eun ju Choi, Andrew D. Miller, Elizabeth Devenish, Makoto Asakawa, Marina McConkey, Jeanine Peters-Kennedy

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The Charcot–Leyden crystal (CLC) is a major human eosinophil protein that readily crystallizes; these crystals are common in eosinophilic diseases. Although anecdotal existence of these crystals is known in veterinary pathology, definitive reports do not exist, to our knowledge. We identified eosinophilic crystals in a laryngeal myxosarcoma from a 2-y-old, spayed female, Labrador Retriever dog that were tentatively interpreted as CLCs. However, Ziehl–Neelsen acid-fast stain was negative, arguing against CLCs. The crystals stained red with Masson trichrome, precluding collagen. Periodic acid–Schiff and alcian blue were negative. The crystals stained positively with Okajima, and no myoglobin immunoreactivity was detected, supporting their identity as hemoglobin crystals. In the absence of a hematologic abnormality, these crystals were interpreted to be abnormal hemoglobin breakdown products. Protein sequence comparison was pursued to determine whether a protein similar to CLC exists in mammals. Only 3 nonhuman primate species, the Sumatran orangutan (Pongo abelii), rhesus macaque (Macaca mulatta), and cynomolgus monkey (Macaca fascicularis), had a sequence similarity of >80%. Of the crystal-forming residues, 12 of 54 (22%) were different in the Sumatran orangutan and 15 of 54 (28%) were different in the Macaca spp., which may affect the crystallization process. The lack of reports of CLCs in nonhuman species and our results collectively suggest that CLCs are human-specific.

Original languageEnglish (US)
Pages (from-to)904-909
Number of pages6
JournalJournal of Veterinary Diagnostic Investigation
Issue number6
StatePublished - Nov 1 2017
Externally publishedYes


  • Charcot–Leyden crystal protein
  • histocytochemistry
  • sequence homology

ASJC Scopus subject areas

  • veterinary(all)


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