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

Abstract

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.

Disseminated Langerhans cell histiocytosis presenting as oesophageal disease in a cat

“…Infiltration of the affected organs by multifocal-to-coalescing nodular masses in the present case are similar to the characteristic feature described in pulmonary LCH. 5,9 Although lesional histiocytes exhibited similar cellular and nuclear descriptions of pleomorphism, there are differences between the present case and reports of pulmonary LCH. Pulmonary LCH has been characterised by cohesive infiltration of histiocytic cells, which obliterate terminal airways and extend to the pleural surface.…”

“…Reported cases have presented primarily with respiratory complaints, lethargy, anorexia or weight loss. 5,9 In our case hyporexia, weight loss and ptyalism were the presenting clinical signs. While ptyalism is a common clinical sign of oesophageal disease, pseudoptyalism from an involuntary disruption of the swallowing mechanism is also a likely consequence of mechanical obstruction from the oesophageal mass.…”

“…Pulmonary LCH has been characterised by cohesive infiltration of histiocytic cells, which obliterate terminal airways and extend to the pleural surface. 5,9 Accompanying inflammatory cells are dominated by lymphocytes, with fewer plasma cells and occasional macrophages. 9 In our case a predilection for terminal airways was not observed and neutrophilic infiltration contributed significantly to the proportion of accompanying inflammatory cells.…”

“…8 Pulmonary LCH has been described in cats as pulmonary disease alone or with multi-organ involvement, including the lungs, pancreas, kidneys, spleen, liver, thyroid, parathyroid gland and tracheobronchial, hepatosplenic and mesenteric lymph nodes. 4,5,9 A study describing the clinical, morphological and immunophenotypic features of feline progressive histiocytosis identified the coexpression of E-cadherin, a marker of LC differentiation, in 3/30 cats and could represent cats with LCH. 10…”

Ophthalmopathologic characterization of multicentric or metastatic neoplasms with an extraocular origin in dogs and cats

“…The amplification signal was obtained with MACH4 universal HRP polymer (Biocare Medical), and the reactions were revealed with chromogen romulin AEC kit (Biocare Medical). In the cases diagnosed as histiocytic sarcoma (HS) in cats and chemodectoma in dogs, additional antibodies were employed to confirm the origin of the cells: monoclonal mouse anti‐human cytokeratin ready‐to‐use (clone AE1/AE3; Dako), monoclonal mouse anti‐vimentin (clone V9, code 180052, Invitrogen), FLEX polyclonal rabbit anti‐thyroglobulin ready‐to‐use (code GA509, Dako), polyclonal rabbit anti‐calcium‐binding protein 1 (Iba‐1; code 019‐19741, Fujifilm Wako Chemicals USA Corporation), polyclonal rabbit anti‐chromogranin A (code A0430; Dako), according to previously described protocols 22,23 . Negative controls consisted of incubating the tissue sections with phosphate‐buffered saline (PBS).…”