Pulmonary Granulomas Associated with PAS-Positive Bodies in Brachycephalic Dogs

Abstract

Abstract. Pulmonary granulomas were incidental findings at necropsy in 18 dogs, mainly of the brachycephalic breeds. These lesions were multifocal along smaller bronchi and the subpleural tissue at the margins of lobes. The granulomatous reaction contained numerous periodic acid-Schiff (PAS)-positive bodies that histochemically had reactions suggestive of a calcium-lipid-mucopolysaccharide complex. Although the cause is not clear, the location and distribution are suggestive of an inhalation or aspiration pneumonia.The shortened muzzle of brachycephalic breeds, particularly when there is concurrent upper respiratory disease, may predispose them to these bodies.Pulmonary granulomas of unknown cause were seen at necropsy as incidental findings in 18 dogs with a mean age of 10 years. All but two dogs were from large metropolitan areas of New York City and Philadelphia. Tissue specimens were submitted to the Armed Forces Institute of Pathology for histologic examination. The gross and histologic features of these lesions are described. Materials and MethodsThe breed, sex, and age of each dog is shown in table I. Parts of the pulmonary lesions were fixed in 10% formalin and embedded in paraffin. Sections were cut at 6 pni and stained with haematoxylin and eosin (HE), periodic acid-Schiff (PAS) with and without diastase, Mowry's modification of the colloidal iron stain for acid mucopolysaccharides (AMP) [4], alizarin red S before and after microincineration, Danielli's stain for tyrosinecontaining proteins, alcian blue, oil red 0, and the Prussian blue reaction for iron. Other stains included Congo red for amyloid, Mayer's mucicarmine, and Gomori's methenaminesilver stain (GMS). X-ray diffraction was performed by the powder method and a DebyeScherrer camera [l].

Pulmonary Hyalinosis in Dogs

“…A report of similar PAS-positive bodies in the lungs of brachycephalic dogs suggested the granulomatous response occurred as a result of inhalation or aspiration pneumonia [2]. The light microscopic appearance of the bodies seemed similar to that of those in this report, but we did not find any ultrastructural details suggestive of aspirated material.…”

Spontaneous Lung Lesions in Aging Laboratory Rabbits (Oryctolagus cuniculus)

“…In 1 study, lesions were predominant in brachycephalic breeds from urban settings, one-third of which had pulmonary or upper respiratory disease thought to predispose to aspiration. 5 The other study found lesions in 30 of 34 beagles exposed to airborne radon daughters (radioactive decay particles) with uranium ore dust and attributed the material to a degenerative response to injury with accumulation of endogenous secretions. 10 All but 1 of the affected EIII/JC described here were unmanipulated breeders, with no known airborne exposures (no history provided for the exception).…”

“…[4][5][6]. Interestingly, some of the smoothelin-positive intimal cells were also vimentin positive, whereas the fully differentiated contractile smooth muscle cells of the media were smoothelinþ/a-SMAþ/vimentinÀ.…”

Pulmonary hyalinosis in captive sugar gliders (Petaurus breviceps)

“…The bodies also display birefringence under polarized light. 1,4 The inciting cause and pathogenesis for this accumulation of pulmonary hyaline material is unknown, but disease is seen predominantly in older dogs and typically is considered incidental. 3 Early descriptions suggested a response to inhalation or aspiration of irritants, including uranium ore dust.…”