Beak fracture associated with leiomyosarcoma in a budgerigar (Melopsittacus undulatus): a case report and literature review.

A 2-year-old male budgerigar (Melopsittacus undulatus) died after a 1-day history of fracture of the rostral rhinotheca with pale mucous membranes, dyspnea, dull mentation, and ataxia. Histopathology revealed an infiltrative neoplasm composed of interweaving streams of spindle cells effacing the dermis and bone of the rostral upper beak as well as a ganglion and two cranial nerves. No visceral metastasis was observed. Neoplastic cells exhibited strong cytoplasmic immunolabeling for alpha-smooth muscle actin (α-SMA) and lacked immunolabeling for S100, Melan-A, PNL2, and cytokeratin AE1/AE3. These findings were consistent with a locally invasive leiomyosarcoma Leiomyosarcomas arise from the smooth muscle and are locally invasive with rare metastases. In birds, leiomyosarcomas are mostly reported to arise from the spleen, gastrointestinal, and reproductive tracts. In the case report herein, we describe the histological and immunohistochemical features of a primary beak leiomyosarcoma in a budgerigar associated with a fracture located at the rostral rhinotheca. Leiomyosarcoma arising from the beak has not been described in the literature.

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

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.

Case Report: Pulmonary Conidiobolomycosis in a Vietnamese Pot-Bellied Pig.

An adult castrated male Vietnamese pot-bellied pig had a 1-week history of acute dyspnea and lethargy. Minimal diagnostic testing was authorized by the owner, resulting in treatment with a third-generation cephalosporin and a non-steroidal anti-inflammatory drug. Partial improvement was observed after a week; however, the pig died 2 weeks after the initial onset of clinical signs. Macroscopically, ~90% of the left lung was effaced by large masses with a caseonecrotic center. Histologic examination revealed eosinophilic granulomas with myriad, intralesional, negatively staining hyphae highlighted by "sleeves" of hypereosinophilic material (Splendore-Hoeppli material). Infection with an oomycete or "zygomycete" (i.e., organisms of the order Entomophthorales or Mucorales) was initially considered. Pan-fungal PCR and sequencing performed on formalin-fixed, paraffin-embedded lung tissue identified Conidiobolus spp., consistent with a diagnosis of primary pulmonary conidiobolomycosis. There are only a few reports of infections with Conidiobolus spp. (and other members of the order Entomophthorales) in swine. Unlike humans and other animal species, conidiobolomycosis in pigs presents more commonly as a primary pulmonary disease rather than rhinofacial or nasopharyngeal disease.