Abstract
Dear Editors,
We read with interest the paper entitled ‘Pulmonary Langerhans cell histiocytosis in cats and a literature review of feline histiocytic diseases’, 1 published OnlineFirst on 12 April 2019 and in this issue of JFMS by Dr Argenta et al, and we would like to congratulate the authors on this publication.
For completeness, we would like to take the opportunity to highlight some missing references in the literature review, including four mentioned here.2–5 In the most recent study, ‘Clinical outcome, PDGFRβ and KIT expression in feline histiocytic disorders: a multicentre study’, published in 2017, we included 15 cases of histiocytic disease in cats with attention to morphological diagnosis, clinical outcome and immunohistochemical expression of tyrosine kinase receptors. All cases underwent a review of the histopathology samples prior to being included in the study and immunohistochemistry was subsequently performed. 2
In the above-mentioned article, we documented a clinical response of feline progressive histiocytosis to chemotherapy and, in one untreated case, we reported spontaneous regression of the cutaneous lesions. 2 Furthermore, the localised form of histiocytic sarcoma (HS) treated with surgery ± chemotherapy or radiotherapy was found to have a longer disease-free interval compared with disseminated disease. Immunohistochemical expression of KIT was negative in neoplastic histiocytic cells in all of the tumours studied, whereas PDGFRβ was highly expressed in 66% of the samples analysed, which may support treatment with tyrosine kinase inhibitors, as documented in some cases in the study.
In addition to this present case series, there are also individual case reports of HS with ocular 3 and brain involvement, 4 and a report of amputation as a treatment option for a localised HS. 5
Footnotes
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