Pathological Features of Salivary Gland Cysts in a Shiba Dog with GM1 Gangliosidosis: A Possible Misdiagnosis as Malignancy

Abstract

ABSTRACT. Salivary gland cysts are often concurrent with GM1 gangliosidosis in Shiba dogs. Although the etiology is unknown, these cysts may be misdiagnosed as malignant due to the accumulation of foamy cells. The present study investigated the cytological, histopathological, immunohistochemical and electron microscopic characteristics of salivary gland cysts in a Shiba dog affected with GM1 gangliosidosis. The salivary gland masses were surgically enucleated and examined clinicopathologically and pathologically in a 7-month-old Shiba dog with GM1 gangliosidosis. Many large cells with rich cytoplasm including vacuoles of various sizes, i.e., foamy cells, were observed in stamp smears from the cut-surface of the masses and histopathologically in major parts of the cyst wall. Some of these foamy cells presented features similar to a spider-web appearance. The foamy cells were confirmed to have originated from macrophages based on marked immunohistochemical expression of vimentin, HLA-DR, lysozyme and Iba1. An ultrastructural study demonstrated electron-dense vesicular structures in the vacuolated cells. Therefore, the masses were diagnosed pathologically as benign salivary gland cysts with accumulation of foamy cells. In conclusion, the histopathological features of the salivary gland cysts in this Shiba dog were similar to those of lipoma and/or liposarcoma. In such cases, immunohistochemical and ultrastructural examinations were useful in the differential diagnosis. Practitioners, clinical pathologists and pathologists should take GM1 gangliosidosis into consideration when they encounter salivary gland cysts in Shiba dogs.

Serial MRI Features of Canine GM1 Gangliosidosis: A Possible Imaging Biomarker for Diagnosis and Progression of the Disease

“…The clinical features of GM1 gangliosidosis in SIDs have been described in detail in several reports ( Table 1 ) [ 1 , 7 , 12 – 15 ]. These clinical features in SIDs are similar to those of the late infantile/juvenile form (type 2) of human GM1 gangliosidosis [ 13 ].…”

Positioning Head Tilt in Canine Lysosomal Storage Disease: A Retrospective Observational Descriptive Study

“…This disease is an autosomal recessive deficiency of β-galactosidase enzyme activity due to a mutation of the GLB1 gene (16). Detailed clinical, imaging, histological, and molecular characteristics have previously been reported (6,(15)(16)(17)(18)(19)(20)(21)(22).…”

“…All affected dogs were definitively diagnosed by pedigree analysis, genetic testing, lysosomal enzyme activity, thin-layer chromatography, or histopathology (see individual references and Table 1). All dogs with each type of LSD included in this study have been previously published, and detailed clinical, imaging, and pathological findings and methodologies of various tests should be referred to in the literature (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Clinical characteristics of each type of LSD are summarized below.…”