Multiple cutaneous mast cell tumors in a pig

Pot-bellied Vietnamese pig with visceral mast cell tumors and mastocytemia

An approximately 12-year-old female Vietnamese Pot-Bellied Pig was presented to the Mississippi State College of Veterinary Medicine Food Animal Service for anorexia of 2 days duration. On physical examination, the patient appeared depressed and lethargic with significantly pale mucus membranes, open mouth breathing, and nostril flaring. On abdominal palpation, the abdomen was tense and uncomfortable. A complete blood count (CBC) and chemistry profile were performed. The CBC revealed significant anemia and mild leukocytosis characterized by mild neutrophilia with a left shift. Mast cells were rarely observed. Hematocrit = 8.1% (RI 22-50), RBC = 1.25 × 10⁶ /μL (RI 3.6-7.8), WBC = 19.85 × 10³ /μL (RI 5.2-17.9), Neutrophils = 15.08 × 10³ /μL (RI 0-11.4), and Bands = 0.993 × 10³ /μL (RI 0-0.019). The chemistry profile was unremarkable with a mildly elevated BUN and slightly decreased total protein and albumin (BUN = 39 mg/dL [RI 4.2-15.1], total protein = 6.2 g/dL [RI 6.6-8.9], and albumin = 2.5 g/dL [RI 3.6-5.0]). An abdominal ultrasound revealed numerous hypoechoic nodules diffusely scattered throughout the hepatic parenchyma. An FNA of one of the hepatic nodules was performed. A mild suppurative component and numerous variably granulated mast cells were observed. A presumptive cytologic diagnosis of mast cell tumor was made. Histopathology was performed, confirming the cytologic interpretation.

Cutaneous mast cell tumors in 11 miniature pigs: a retrospective study

Better understanding of mast cell tumors (MCTs) in miniature pigs is needed to guide diagnosis and establish clinical significance. We characterized the gross pathology, histopathology, histochemical staining, and KIT immunoreactivity of cutaneous MCTs in a retrospective descriptive study of 11 miniature pigs (Sus scrofa domesticus). Tumors were single or multiple papules, small nodules, or plaques. In one pig, lymph nodes and internal organs were affected. Histologically, all MCTs involved the dermis, and some extended to the subcutis (4 of 11) and skeletal muscle (1 of 11). Most tumors were well-demarcated, unencapsulated, nodular or multinodular masses (8 of 11) and fewer were poorly demarcated plaques (3 of 11). Neoplastic cells were often well-differentiated with pale amphophilic-to-eosinophilic faintly granular cytoplasm, occasional binucleation, rare multinucleation, and a low mitotic count (<7 per 10 hpf; 10 of 11). Eosinophils were present in tumors in all cases. Cytoplasmic granules stained most consistently with high-pH (2.5-3) toluidine blue (9 of 10) compared to low-pH (0.5-1) toluidine blue (6 of 9) or Giemsa (7 of 10). KIT immunoreactivity patterns were strong perimembranous (4 of 8), focal perinuclear and stippled cytoplasmic (1 of 8), and diffuse cytoplasmic (3 of 8), and included 1 case that was negative for histochemical stains; hence, KIT is a promising diagnostic marker for MCTs in miniature pigs.

Neoplastic lesions in domestic pigs detected at slaughter: literature review and a 20-year review (1998-2018) of carcass inspection in Catalonia

Background

The present paper reviews the occurrence of neoplasms in swine and presents a case series of 56 tumors submitted to the Slaughterhouse Support Network (Servei de Suport a Escorxadors [SESC] IRTA-CReSA]) from slaughtered pigs from 1998 to 2018 (April) in Catalonia (Spain). The aim of the study was to describe the spectrum of spontaneous neoplastic lesions found in slaughtered pigs and to compare the reported tumor cases with previous published data. Lymphoid neoplasms were characterized and classified using the WHO classification adapted for animals.

Results

The most reported neoplasm during this period was lymphoma (28). Within lymphomas, the B-cell type was the most common, being the diffuse large B-cell lymphoma (15/28) the most represented subtype. Other submitted non-lymphoid neoplasms included melanoma (7), nephroblastoma (3), mast cell tumor (2), liposarcoma (2), osteochondromatosis (2), papillary cystadenocarcinoma (1), peripheral nerve sheath tumor (1), lymphoid leukemia (1), fibropapilloma (1), hemangiosarcoma (1), hepatoma (1), histiocytic sarcoma (1), pheochromocytoma (1) and osteosarcoma (1).

Conclusions

The existence of a well-established Slaughterhouse Support Network allowed the compilation of comprehensive data for further epidemiological and pathological studies, particularly about less commonly reported lesions in livestock such as neoplasms in pigs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40813-021-00207-0.

Will donor-derived neoplasia be problematic after clinical pig organ or cell xenotransplantation?

There is an increased incidence of certain tumors and other neoplastic disease in organ allotransplant recipients receiving immunosuppressive therapy. Following clinical pig organ xenotransplantation, will there be a risk of the development of neoplasia in the pig graft or in other tissues transplanted with it, eg, lymph nodes? The incidence of neoplasia in young slaughterhouse pigs is very low (<0.005%), but in older pigs is largely unknown (as most pigs are killed within the first six months of life). However, lymphosarcoma, nephroblastoma, and melanoma have been reported in pigs. These tumors should be readily identified by ultrasound or direct inspection and palpation before an organ is excised for clinical xenotransplantation, and so transfer to the human recipient should be unlikely. Post-transplant lymphoproliferative disorder (PTLD) has been reported in pigs receiving intensive immunomodulatory therapy, particularly if this includes whole body irradiation, in an effort to induce mixed hematopoietic chimerism and immunological tolerance. However, the pigs used as sources of organs in xenotransplantation should be free of the porcine lymphotropic herpesvirus that is a key causative factor for PTLD in pigs, and so donor-derived PTLD should not occur. We conclude that the risk of a malignant tumor developing in a transplanted organ from a young pig is small.

Subcutaneous malignant mast cell tumor in a Japanese macaque (Macaca fuscata)

The histopathological, immunohistochemical, and ultrastructural morphologic characteristics of a tumor in the subcutaneous tissue of the chest of a 19-year-old female Japanese macaque were investigated. Consequently, the mass was diagnosed as a malignant mast cell tumor (MCT). Tumors were present in both mammary gland portions of the anterior thorax. Both tumors showed the same histopathological findings. The tumor tissue was defined by the presence of delicate connective tissue, and the tumor cells grew in a cord-like or cobblestone pattern. The tumor cell cytoplasm was very clear. The nuclei were relatively uniform and the cells showed a low nucleus-cytoplasm ratio. The cytoplasmic granules stained blue with Alcian blue and eosinophils had infiltrated into the tumor tissue. Furthermore, immunohistochemical analysis revealed that the tumor cell membrane was positive for the anti-c-kit antibody. In ultrastructural morphologic analyses, all tumor cells showed a rich cytoplasm and, occasionally, granules wrapped in a limiting membrane of high electron density. The tumor cells had metastasized to the axillary lymph nodes, the kidney, and the peritoneum. Based on these results, the mass was diagnosed as a malignant MCT originating from the subcutaneous tissue of the chest. Since cases of MCTs in macaques are very rare, this report presents important new knowledge of neoplastic lesions in this species.

Six-Year Follow-up of Slaughterhouse Surveillance (2008-2013): The Catalan Slaughterhouse Support Network (SESC)

Meat inspection has the ultimate objective of declaring the meat and offal obtained from carcasses of slaughtered animals fit or unfit for human consumption. This safeguards the health of consumers by ensuring that the food coming from these establishments poses no risk to public health. Concomitantly, it contributes to animal disease surveillance. The Catalan Public Health Protection Agency (Generalitat de Catalunya) identified the need to provide its meat inspectors with a support structure to improve diagnostic capacity: the Slaughterhouse Support Network (SESC). The main goal of the SESC was to offer continuing education to meat inspectors to improve the diagnostic capacity for lesions observed in slaughterhouses. With this aim, a web-based application was designed that allowed meat inspectors to submit their inquiries, images of the lesions, and samples for laboratory analysis. This commentary reviews the cases from the first 6 years of SESC operation (2008-2013). The program not only provides continuing education to inspectors but also contributes to the collection of useful information on animal health and welfare. Therefore, SESC complements animal disease surveillance programs, such as those for tuberculosis, bovine cysticercosis, and porcine trichinellosis, and is a powerful tool for early detection of emerging animal diseases and zoonoses.

Neoplasmas em suínos: 37 casos

Resumo: Neoplasmas em suínos são raros. Esse trabalho descreve os neoplasmas encontrados em suínos na rotina diagnóstica de um laboratório de patologia veterinária localizado na Região Central do Rio Grande do Sul. Durante um período de 49 anos, 2.266 casos de várias afecções em suínos foram encontrados, dos quais 37 (1,6%) eram neoplasmas. Em ordem decrescente de frequência, os seguintes neoplasmas foram encontrados: Linfoma (11/37), nefroblastoma (11/37), melanoma (8/37) e papiloma (2/37). Adicionalmente, um caso de cada um dos seguintes tumores foi observado: Adenoma hepatocelular, carcinoma hepatocelular, colangiocarcinoma, histiocitoma fibroso maligno e sarcoma granulocítico. O aspecto macroscópico e histológico desses tumores é descrito e a sua epidemiologia é comparada com os dados disponíveis na literatura para neoplasia suína.

The porcine innate immune system: an update

Over the last few years, we have seen an increasing interest and demand for pigs in biomedical research. Domestic pigs (Sus scrofa domesticus) are closely related to humans in terms of their anatomy, genetics, and physiology, and often are the model of choice for the assessment of novel vaccines and therapeutics in a preclinical stage. However, the pig as a model has much more to offer, and can serve as a model for many biomedical applications including aging research, medical imaging, and pharmaceutical studies to name a few. In this review, we will provide an overview of the innate immune system in pigs, describe its anatomical and physiological key features, and discuss the key players involved. In particular, we compare the porcine innate immune system to that of humans, and emphasize on the importance of the pig as model for human disease.

Porcine intestinal mast cells. Evaluation of different fixatives for histochemical staining techniques considering tissue shrinkage

Staining of mast cells (MCs), including porcine ones, is critically dependent upon the fixation and staining technique. In the pig, mucosal and submucosal MCs do not stain or stain only faintly after formalin fixation. Some fixation methods are particularly recommended for MC staining, for example the fixation with Carnoy or lead salts. Zinc salt fixation (ZSF) has been reported to work excellently for the preservation of fixation-sensitive antigens. The aim of this study was to establish a reliable histological method for counting of MCs in the porcine intestinum. For this purpose, different tissue fixation and staining methods that also allow potential subsequent immunohistochemical investigations were evaluated in the porcine mucosa, as well as submucosa of small and large intestine. Tissues were fixed in Carnoy, lead acetate, lead nitrate, Zamboni and ZSF and stained subsequently with either polychromatic methylene blue, alcian blue or toluidine blue. For the first time our study reveals that ZSF, a heavy metal fixative, preserves metachromatic staining of porcine MCs. Zamboni fixation was not suitable for histochemical visualization of MCs in the pig intestine. All other tested fixatives were suitable. Alcian blue and toluidine blue co-stained intestinal goblet cells which made a prima facie identification of MCs difficult. The polychromatic methylene blue proved to be the optimal staining. In order to compare MC counting results of the different fixation methods, tissue shrinkage was taken into account. As even the same fixation caused shrinkagedifferences between tissue from small and large intestine, different factors for each single fixation and intestinal localization had to be calculated. Tissue shrinkage varied between 19% and 57%, the highest tissue shrinkage was found after fixation with ZSF in the large intestine, the lowest one in the small intestine after lead acetate fixation. Our study emphasizes that MC counting results from data using different fixation techniques can only be compared if the respective studyimmanent shrinkage factor has been determined and quantification results are adjusted accordingly.