Cytology Q&A 11

This question was provided by Manson Publishing as part of the OVAL Project. See more Cytology Q&A.

An FNA was collected from a firm, painless mass on the shoulder of a Thoroughbred gelding.

Question	Answer		Article
What cells are present in this smear (Wright–Giemsa, ×100 oil)?	A mixed cell population, mainly of neutrophils, with many reactive macrophages, disrupted eosinophils (in other fields) and a mast cell (top right). Microorganisms are not seen.		Link to Article
What is your diagnosis?	Chronic, active and eosinophilic sterile inflammation. Note: Eosinophils may be seen as a part of a nonspecific inflammatory response, but considerations should include the possibility of a reaction to a foreign body, migrating parasite, fungal or yeast infection, habronemiasis, or irritation due to fly bites or ulceration (not seen in this case). Eosinophilic inflammation in the horse is a relatively common finding and a specific underlying cause may not always be apparent.		Link to Article