Immunohistochemical Distinguishing between Canine Peripheral Nerve Sheath Tumors and Perivascular Wall Tumors

Abstract

Peripheral nerve sheath tumors (PNSTs) comprise a heterogeneous group of neoplasms originating from the elements of the nerve sheath. They are divided into two forms: benign and malignant PNST. Both benign and malignant PNSTs are not very common in domestic animals but they are reported in different animal species. Histologically, PNSTs are composed predominantly of spindle cells arranged in bundles, whorls and sheets, with a different number of pleomorphic cells and mitotic figures. The aim of this study was a reclassification of 17 dog tumor samples initially diagnosed with peripheral nerve sheath tumors using histopathological analysis. The main criterion for reclassification was immunohistochemical positivity for various antigens. PNSTs are often histologically very similar to other spindle cell tumors and immunohistochemistry is required for differential diagnosis. PNSTs generally express vimentin, S-100 protein, glial fibrillary acidic protein (GFAP), collagen IV and laminin. Four tumor samples were positive to muscular marker α-SMA and vimentin and negative for S-100 protein and desmin. The spindle cells whirling around some blood vessels were observed in these tumors so they were reclassified as perivascular wall tumors (PWTs). The other 13 tumors were S-100 protein and vimentin positive and α-SMA and desmin negative, thus classified as PNST. The use of the immunohistochemical panel is necessary for distinguishing PNSTs from PWTs in routine diagnostics.

Prevalence and distribution of canine neoplastic and non-neoplastic cutaneous lesions in Serbia: a retrospective study of 2432 Cases (2011 – Mid 2021)

“…In contrast to our results, Graf et al (2018) report a slightly higher proportion of perivascular wall tumor (4.57%), but a lower prevalence of peripheral nerve sheath tumor (0.09%) [11]. In some cases, due to a similar histologic pattern, the differentiation between these two tumor types requires certain antibodies for immunohistochemistry [27].…”

Comparative whole transcriptome analysis of gene expression in three canine soft tissue sarcoma types

“…The present study examined tumor-type specific gene expression patterns in canine soft tissue sarcomas using RNA-seq of formalin-fixed, paraffin-embedded (FFPE) samples. Although the sample size used in this study was small, the number of samples for each tumor type was consistent with that used in several previous studies [17,28,[52][53][54]. Importantly, our sample size was sufficient to identify 3256 differentially expressed genes among these three distinct tumor types with high statistical significance.…”

International Guidelines for Veterinary Tumor Pathology: A Call to Action

“…A particular conundrum is differentiating PWT from NST. Histologic features characteristic of PWT and NST have been described, but there is overlap of histologic patterns found in these 2 tumor types, 9,10,71,97,113,124 which can complicate definitive diagnosis in routinely stained sections. How specific can, or should our diagnoses be from HE slides and how does this influence differentiation scores used to grade these tumors?…”