Canine Laryngeal Rhabdomyoma

Abstract

Abstract. Three canine laryngeal tumors were diagnosed as oncocytomas by light microscopy, but were determined to be rhabdomyomas following ultrastructural and immunocytochemical examination. Tumors consisted of large eosinophilic cells interspersed with smaller dark cells. Large tumor cells had a granular, intensely eosinophilic cytoplasm. Scattered through the tumors were a few elongated cells with cytoplasmic cross striations and multiple nuclei. Tumor cells from all three dogs contained numerous mitochondria and bundles of myofibrils with electron-dense Z-lines typical of striated muscle cells. Intracellular myoglobin and desmin were detected in the tumors by immunocytochemistry. Comparisons are made with a previous report of canine laryngeal oncocytomas.Oncocytes are considered to be epithelial cells. They are found as single cells or small clusters of cells in a variety of organs, such as, thyroid (Hiirthle cells), parathyroid (oxyphil cells), pituitary, adrenal, salivary glands, larynx, trachea, bronchi, nasopharynx, tongue, and liver.1,6.11.14,16,21 0 ncocytes are intensely eosinophilic, are packed with mitochondria and have a concurrent reduction in other cellThe majority of reported oncocytomas are case studies in people.2. 6-8. 13.23 Three canine laryngeal oncocytomas have been described." Many of the clinical, macroscopic, microscopic, and ultrastructural characteristics of these canine oncocytoma~'~ are similar to the laryngeal tumors described in this study. We describe three canine laryngeal tumors that were originally diagnosed as oncocytomas by light microscopy, but were confirmed to be of striated muscle origin by electron microscopy and immunocytochemistry. Materials and MethodsFour la -yngsal tumors were examined from the three dogs studied. T h r x tumors were primary and one was a local recurrence. Tumors were placed in 10% buffered neutral formalin, embedded in paraffin, and stained with hematoxylin and eosin (HE), periodic acid-Schiff (PAS), PAS with diastase, and phosphotungstic acid-hematoxylin. Thin slices of tumor from dog 1 were transferred to Trump's'' fixative after several weeks in formalin. Tissues were then rinsed in phosphate buffer (pH 7.2), placed in 1 % osmium tetroxide, rinsed in distilled water, and dehydrated in ascending concentrations of ethanol. Tissues were embedded in Spurr's resin"; thick sections were stained with toluidine blue, and thin sections were stained with alcoholic uranyl acetate followed by lead citrate. Tissues for electron microscopy from dogs 2 and 3 were deparaffinized and then processed similarly for transmission electron microscopy. Previous diagnosis on the tumors from both of these dogs were o n c o~y t o m a .~,~ Immunocytochemistry for desmin and myoglobin was done on paraffin-embedded sections from all four tumors. Sections of skeletal muscle and liver were used as positive and negative controls. Briefly, deparaffinized sections were incubated in rabbit antiserum specific for myoglobin or desmin (Dako Corp., Santa Barbara, Calif.) overnight at...

Bilateral Renal Oncocytoma in a Greyhound Dog

“…In the dog, oncocytomas have been reported originally in the larynx and recently in the thyroid gland. 7,9,15 There is one report of a chromophilic-eosinophilic (oncocyte-like) renal cell carcinoma in a dog. 18 The authors described two different oncocyte-like populations of tumor cells and concluded from their morphologic and immunohistochemical studies that the tumor in that dog resembled a renal oncocytoma more than a renal carcinoma.…”

“…3 Rhabdoid tumors ultrastructurally contain mitochondria and aggregates of myofilaments. [7][8][9] Specific immunohistochemical markers are helpful in making a differential diagnosis. Oncocytomas specifically express cytokeratin, 15,17 whereas renal cell carcinomas coexpress vimentin and cytokeratin.…”

“…10 Rhabdoid tumors react positively for desmin and intracellular myoglobin. 9 The expression of intermediate filament proteins in subtypes of renal cell carcinomas and in renal oncocytomas makes it possible to distinguish between two classes of renal cell tumors. The consistent absence of The diagnosis of oncocytoma in this dog primarily was based on immunohistochemical and electron microscopic features.…”

Congenital Fetal Rhabdomyoma in a Foal

“…The clinical presentation of a congenital subcutaneous mass with the histologic pattern described for this case are similar to the features seen in human FR and are distinctly different from the previous AR-like rhabdomyomas described in animals. 5,6,8 This is to our knowledge the first veterinary description of a 1) fetal rhabdomyoma and 2) an extracardiac congenital rhabdomyoma.…”

Endoscopic approach for a laryngeal neoplasm in a dog

“…The laryngeal neoplasms reported in dogs were rhabdomyomas, extramedullaryplasmacytomas, chondrosarcomas, carcinomas, fi brosarcomas and mastocytomas (MEUTEN et al, 1985;HAYES et al, 2007;MACPHAIL, 2014). Except for the rhabdomyomas, most of these neoplasms are locally invasive and have a high metastatic potential (WITHROW, 2013).…”