Primary Malignant Peripheral Nerve Sheath Tumor with Eosinophilic Cytoplasmic Globules Arising from the Greater Omentum in a Dog

Abstract

ABSTRACT. A 10-year-old Golden Retriever dog had a solitary tumor mass arising from the greater omentum. Histologically, the tumor showed varying cellularity and patterns of cellular arrangement. In dense cellular areas, spindle-shaped cells were arranged in interlacing bundles. The sparse cellular area was characterized by loosely arranged fusiform cells. The neoplastic cells frequently contained PASpositive eosinophilic globules in the cytoplasm, and mitotic figures were frequently observed. The tumor cells were positive to vimentin, S-100 protein, glial fibrillary acidic protein, myelin basic protein, neuron-specific enolase and myoglobin. The present tumor was diagnosed as a malignant peripheral nerve sheath tumor (MPNST) with eosinophilic cytoplasmic globules arising from the greater omentum. To our knowledge, this may be the first case of primary omental MPNST in domestic animals. KEY WORDS: canine, greater omentum, malignant peripheral nerve sheath tumor.J. Vet. Med. Sci. 70 (7): [739][740][741][742] 2008 Primary omental tumors are extremely rare in animals. A search of the literature in English over the past 20 years revealed no reports of only two tumors (lipoma and liposarcoma) in 2 dogs [3,8]. Moreover, only a few cases of a primary tumor of the peripheral nerves arising from the greater omentum have been reported in humans [2,11], but none in domestic animals.Malignant tumors arising from peripheral nerves or displaying differentiation along the lines of the various elements of the nerve sheath are collectively referred to as malignant peripheral nerve sheath tumors (MPNSTs) [24]. Human MPNSTs occasionally show histologic evidence of focally divergent differentiation to rhabdomyosarcoma, osteosarcoma, chondrosarcoma, angiosarcoma, epithelial elements, or a combination thereof [9,24] [6,15,21]. Our report describes a canine MPNST with cytoplasmic globules arising from the greater omentum.A 10-year-old neutered-male Golden Retriever was referred with a 1-week history of anorexia without vomiting or diarrhea. Ultrasonography showed a large, solitary, welldefined and extrahepatic mass close to the liver with a smooth surface and non-homogeneous echo levels. Computed tomography (CT) detected a large mass in the left upper abdomen (Fig. 1).The mass was surgically resected and, upon gross examination, was found to have arisen from the greater omentum and to reveal a smooth, dark whitish red surface with edematous areas (Fig. 2). The mass measured 17 × 11 × 8 cm in diameter and weighed 1,500 g. The cut surface showed solid tissue with hemorrhaging, necrosis and multiple cysts containing a dark red fluid. The tumor did not invade or adhere to other organs, and no metastasis or ascites was observed.The resected tissue was fixed in 10% formalin and embedded in paraffin wax. Sections were cut at 5 µm and stained with haematoxylin and eosin (HE) and periodic acid-Schiff (PAS) with or without diastase digestion. For

Primary Splenic Peripheral Nerve Sheath Tumour in a Dog

“…Although rare, PNSTs arising within the thoracic cavity and abdomen have been described in man (Bui et al, 2004;Khan et al, 2006;Rahman et al, 2006;Vyas et al, 2006;Tashiro et al, 2007), horses (Pascoe, 1982;Andreasen et al, 1993;Kirchhof et al, 1996;Stoica et al, 2001;Quinn et al, 2005), dogs (Stoica et al, 2001;Essman et al, 2002;Aupperle et al, 2007;Patterson et al, 2008;Sugiyama et al, 2008), cats (Stoica et al, 2001) and cattle (Stoica et al, 2001). Herein we report the clinical, microscopical and immunohistochemical findings related to the occurrence of a PNST within the of a dog.…”

Computed tomography of suppurative and neoplastic diseases involving the canine omenta and omental bursa

“…Primary omental neoplasms are sporadically described in the veterinary literature, limited to a case series describing dogs with omental hemangiosarcoma and case reports of various other neoplasms such as rhabdomyosarcoma, myxosarcoma, peripheral nerve sheath tumor, and mesothelioma. 7,11,[19][20][21] Thus information about clinical outcomes in these dogs related to CT and surgery is limited. In this study, the major limitations were the small sample population and the retrospective design.…”

Case report: Presumptive subcutaneous malignant peripheral nerve sheath tumor with intracranial invasion and osteolysis in the posterior fossa of a dog

“…Depending on the site of origin, MPNST treatment includes local therapy, such as surgical resection ( 2 – 4 , 13 , 27 ), radiation therapy ( 28 , 29 ), or palliative therapy. However, a radical cure cannot be expected owing to the high local recurrence rate.…”

“…In MPNSTs, distant metastasis is uncommon, while local invasiveness is high. In addition to the peripheral nerves, PNSTs in dogs are derived from the central nervous system (CNS) and various other sites (1), including the greater omentum, adrenal gland, and third eyelid (2)(3)(4), with clinical signs and prognosis differing according to the site. MPNSTs have been reported in the intracranial region (5)(6)(7).…”