Retrospective canine skin peripheral nerve sheath tumors data with emphasis on histologic, immunohistochemical and prognostic factors

Abstract

In this retrospective study was determined the frequency of canine skin peripheral nerve sheath tumors (PNST) in cases diagnosed by the Setor de Patologia Veterinária of the Universidade Federal do Rio Grande do Sul (SPV-UFRGS), Brazil, between the years 2000 and 2012. The canine profiles, as well as histological, immunohistochemical and prognostic aspects of the tumors were based on 70 samples, comprising 40 females, 29 males and one unspecified sample. Between 2000 and 2012, 2,984 skin tumors of dogs were diagnosed in the SPV-UFRGS, totaling 2.34% of skin neoplasms in dogs. Animals that comprised the largest amount of samples (43%) were those with no breed (SRD), followed by German Shepherds (10%). Females were more affected than males (40/70 - 57% and 29/70 - 41% respectively). Skin PNST of this research showed predominant localization on the limbs (40% in the forelimbs and 29% in the hindlimbs); affecting adult dogs, mostly aged between 8 and 11 years (54%). The samples were routinely processed for hematoxylin and eosin, and were also evaluated by toluidine blue and Masson's trichrome staining, and immunohistochemistry (IHC) anti-vimentin, -S-100, -GFAP, -actin, von Willebrand factor and neurofilament. Anisocytosis and anisokaryosis, mitotic index, intratumoral necrosis, invasion of adjacent tissues, tumor location, local recurrence and metastasis were related to the diagnosis of benign (49/70) or malignant tumor (21/70). The Antoni A histological pattern was observed more frequently in benign tumors. The immunohistochemistry helped to diagnose PNST, and anti-vimentin and anti-protein S-100 showed the highest rates of immunostaining. Throughout statistical analysis of animals with tumor recurrence, it was found that the chance of an animal with a malignant peripheral nerve sheath tumor to develop recurrence is 4.61 times higher than in an animal that had a benign tumor.

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

“…That PNSTs are generally positive for vimentin, revealed also Chijiwa et al, 2004 [3] in which study all 100% of examined tumors were vimentinpositive, as well as Teixeira et al 2016 [20] with 95% positive cases, but with different expression intensity between the benign and the malignant cases. Negative vimentin staining was observed in MPNSTs very rarely and that could be explained by very low differentiation of malignant cells [9].…”

“…However, a histopathological examination may be suffi cient for primary diagnosis, but it is usually necessary to perform an immunohistochemical analysis in order to distinct PNST from PWT. Besides PWT, fi brosarcomas and amelanotic melanomas are often found to be of signifi cance for the differential diagnosis [9].…”

“…According to morphologic features and biologic behavior, PNSTs are divided into two forms: benign PNST (BPNST) and malignant PNST (MPNST) [3]. Generally, BPNSTs are not very common in domestic animals but they are reported in different animal species, such as cat, horse, pig and goat [4][5][6][7] and most frequently are seen in dogs and cattle [8,9]. Likewise, MPNSTs are rare in animals and in dogs, they account for 27% of all nervous system tumors [1,10].…”

Canine sarcomas as a surrogate for the human disease

“…These tumors can occur anywhere in the body and are classified as peripheral (away from the brain and spinal cord), root (directly adjacent to the brain or spinal cord), or plexus (adjacent to the brachial or lumbosacral plexus) with the peripheral form having the most favorable treatment outcomes (Brehm, Vite, Steinberg, Haviland, & van Winkle, 1995). A recent retrospective analysis suggests that PNST does not have strong breed prevalence, but German Shepherds may be more susceptible as well as females (Boos et al, 2015). Progression of PNST is usually due to local recurrence and invasion, with distant metastasis occurring less frequently.…”

Achados patológicos e imuno-histoquímicos de neoplasmas pulmonares primários em caninos na região metropolitana de Porto Alegre, Rio Grande do Sul

“…Tumores da bainha de nervo periférico maligno de pulmão, é extremamente raro em animais (Dungworth et al 1999) e em humanos (Togashi et al 2003, Domen et al 2010. Como diagnóstico diferencial de tumor da bainha de nervo periférico maligno podem ser incluídos fibrossarcoma, hemangiopericitoma e melanoma amelanótico (Boos et al 2015). A imunomarcação para proteína S-100 é importante para diferenciar tumor da bainha de nervo periférico de fibrossarcoma, pois o último não exibe marcação para esta proteína (Gross et al 2009).…”