Extramedullary plasmacytoma of the oral cavity metastasising to both kidneys in a dog.

BACKGROUND: Most extramedullary plasmacytomas (EMPs) aresolitary and located in the head and neck region. They may also occur in the visceral parts of the body. OBJECTIVES: Here, we report a case of oral EMP followed by neoplastic plasma cell metastasis to both kidneys in a neutered male Pomeranian. METHODS: Oral plasmacytoma recurred 11 months aftersurgical removal of an oral mass and partial maxillectomy was performed. Eighteen months after partial maxillectomy, neoplastic masses were detected in both kidneys on computed tomography. The dog died 12 months after detection of bilateral kidney neoplasms. The resected neoplastic masses were routinely processed for histopathological observation and immunohistochemistry against pan-cytokeratin, desmin, CD3, and MUM-1. RESULTS: The recurred mass mainly consisted of well-differentiated plasma cells and contained a small portion of aggressive cells with malignant features. Monoclonal gammopathy was not observed on serumelectrophoresis performed to exclude multiple myeloma. The mass was composed of plasma cells with high nuclear pleomorphism and abundant mitotic figures. The neoplasm stained positive for MUM-1 with a more aggressive morphology than in oral EMP. CONCLUSION: Based on serum biomarker and pathological observations, a diagnosis of recurrence and metastasis of oral-to-renal EMP was established. To the best of our knowledge, metastasis of oral EMP into the bilateral kidneys, as described in the current case, has not been previously reported in dogs.

Apocrine cystomatosis: From the aspect of epithelial-mesenchymal transition.

Apocrine cystomatosis, also called epitrichial sweat gland cystomatosis, is a non-neoplastic condition characterised by multiple dilated cysts of sweat gland origin. Histopathologically, these cysts comprise two layers of cells: an inner layer of glandular epithelial cells and an outer layer of myoepithelial cells. A case of apocrine cystomatosis was admitted to a local hospital. The microscopic investigation revealed that some enlarged cysts showed the transition of glandular epithelial cells into a spindle, mesenchymal cell-like morphology. The epithelial-to-mesenchymal transition (EMT) has long been studied as a pathway for embryogenesis, organ development, and carcinogenesis. While various molecular factors, including cytokines and growth factors, are known to induce EMT, mechanical forces have also been proposed to initiate EMT. The present case describes a possible relationship between EMT occurring in a cystic condition and further pathological inspection.

Nogo-A Is Critical for Pro-Inflammatory Gene Regulation in Myocytes and Macrophages.

Nogo-A (Rtn 4A), a member of the reticulon 4 (Rtn4) protein family, is a neurite outgrowth inhibitor protein that is primarily expressed in the central nervous system (CNS). However, previous studies revealed that Nogo-A was upregulated in skeletal muscles of Amyotrophic lateral sclerosis (ALS) patients. Additionally, experiments showed that endoplasmic reticulum (ER) stress marker, C/EBP homologous protein (CHOP), was upregulated in gastrocnemius muscle of a murine model of ALS. We therefore hypothesized that Nogo-A might relate to skeletal muscle diseases. According to our knocking down and overexpression results in muscle cell line (C2C12), we have found that upregulation of Nogo-A resulted in upregulation of CHOP, pro-inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α, while downregulation of Nogo-A led to downregulation of CHOP, IL-6 and TNF-α. Immunofluorescence results showed that Nogo-A and CHOP were expressed by myofibers as well as tissue macrophages. Since resident macrophages share similar functions as bone marrow-derived macrophages (BMDM), we therefore, isolated macrophages from bone marrow to study the role of Nogo-A in activation of these cells. Lipopolysaccharide (LPS)-stimulated BMDM in Nogo-KO mice showed low mRNA expression of CHOP, IL-6 and TNF-α compared to BMDM in wild type (WT) mice. Interestingly, Nogo knockout (KO) BMDM exhibited lower migratory activity and phagocytic ability compared with WT BMDM after LPS treatment. In addition, mice experiments data revealed that upregulation of Nogo-A in notexin- and tunicamycin-treated muscles was associated with upregulation of CHOP, IL-6 and TNF-α in WT group, while in Nogo-KO group resulted in low expression level of CHOP, IL-6 and TNF-α. Furthermore, upregulation of Nogo-A in dystrophin-deficient (mdx) murine model, myopathy and Duchenne muscle dystrophy (DMD) clinical biopsies was associated with upregulation of CHOP, IL-6 and TNF-α. To the best of our knowledge, this is the first study to demonstrate Nogo-A as a regulator of inflammation in diseased muscle and bone marrow macrophages and that deletion of Nogo-A alleviates muscle inflammation and it can be utilized as a therapeutic target for improving muscle diseases.