Feline Pulmonary Langerhans Cell Histiocytosis with Multiorgan Involvement

Histiocytic proliferative diseases are uncommon in cats, although recently a progressive histiocytosis of the skin with terminal involvement of internal organs has been described in cats. Here we describe 3 cats (2 males and 1 female) with pulmonary Langerhans cell histiocytosis (PLCH). The cats were euthanized due to progressive respiratory clinical symptoms and deterioration. Macroscopically, extensive, multifocal to confluent, pulmonary masses were evident. Infiltration of pancreas (2 cats), kidneys (1 cat), liver (1 cat), as well as tracheobronchial, hepatosplenic, or mesenteric lymph nodes (2 cats) was observed by gross or microscopic examination. The infiltrating cells had histiocytic morphology with cytologic atypia characterized by anisokaryosis and hyperchromasia regionally within infiltrated tissues. Lesional histiocytes expressed vimentin, CD18, and E-cadherin. Expression of E-cadherin was usually markedly reduced in extra-pulmonary lesions, which is consistent with possible down-regulation of E-cadherin associated with distant migration from the lung. Transmission electron microscopy demonstrated intracytoplasmic organelles consistent with Birbeck's granules of Langerhans cells in the lesional histiocytes in all cats, except in the pancreas of one cat. These findings were compatible with PLCH with limited organ involvement of humans. It remains unproven whether feline PLCH represents a reactive or neoplastic cell proliferation.

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Pulmonary Langerhans cell histiocytosis in cats and a literature review of feline histiocytic diseases

Journal of Feline Medicine and Surgery ◽

10.1177/1098612x19842384 ◽

2019 ◽

Vol 22 (4) ◽

pp. 305-312 ◽

Cited By ~ 3

Author(s):

Fernando Froner Argenta ◽

Fernanda Cristina de Britto ◽

Paula Reis Pereira ◽

Daniel Ricardo Rissi ◽

Cristiano Gomes ◽

...

Keyword(s):

Literature Review ◽

Langerhans Cell Histiocytosis ◽

Clinical Signs ◽

Clinical Information ◽

Langerhans Cell ◽

Fungal Culture ◽

Pulmonary Langerhans Cell Histiocytosis ◽

Pulmonary Parenchyma ◽

Clinical Records ◽

E Cadherin

Objectives The aim of this study was to report the clinical, radiographic and pathological features of pulmonary Langerhans cell histiocytosis in four cats, and carry out a literature review of feline histiocytic diseases. Methods Necropsy reports archived at the Department of Veterinary Pathology of the Federal University of Rio Grande do Sul were reviewed. The clinical information was then obtained from the clinical records at the Veterinary Hospital. Routine samples had been collected during necropsy, fixed in 10% formalin, routinely processed for histology, and stained with hematoxylin and eosin. Samples of lung were submitted for bacterial and fungal culture. Tissue sections of lung underwent immunohistochemical testing for vimentin, pancytokeratin, CD18, CD3, CD79αcy, E-cadherin and Iba1. Results This disease affected mixed breed cats aged 7–14 years. Clinical signs consisted of severe mixed inspiratory and expiratory restrictive dyspnea, lethargy and anorexia. Thoracic radiographs revealed different lesion profiles, predominantly of an interstitial and alveolar pattern. Grossly, the lungs were diffusely firm and did not collapse. The pleural surface was bright and irregular due to multifocal-to-coalescent, well-demarcated, white, firm nodules that also extended into and obliterated the pulmonary parenchyma. Histological changes were characterized by poorly demarcated infiltration with histiocytic cells arranged in cohesive groups within the alveolar, bronchiolar and bronchial spaces. Histiocytic cells had intense cytoplasmic immunolabeling for vimentin and Iba1, and robust membrane immunolabeling with CD18 and E-cadherin; these cells were negative for CD3, CD79αcy and pancytokeratin in all cases. Conclusions and relevance This article confirms that pulmonary Langerhans cell histiocytosis is a rare disease that occurs in middle-aged to older cats and causes widespread involvement of the pulmonary parenchyma, inducing acute or chronic, progressive respiratory disease characterized by mixed restrictive dyspnea that eventually leads to death. While a definitive clinical diagnosis is challenging, the nodular appearance of the pulmonary changes, together with the histological and immunohistochemistry findings, suffice for diagnostic confirmation of pulmonary Langerhans cell histiocytosis.

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