case_images: PMC10739488_01
case_images: (A) 2-year-old male blue budgerigar (Melopsittacus undulatus) submitted for post-mortem examination. (B) The rostral portion of the rhinotheca was absent with jagged lateral edges (black arrows), incomplete occlusion, and mild hemorrhagic staining of the surrounding feathers.
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case_images: PMC10739488_01_fvets-10-1309185-g001.jpg
case_images: fig1
case_images: On postmortem examination, the rostral portion of the rhinotheca was absent with jagged lateral edges and incomplete occlusion (Figure 1).
case_images: (A) Subgross photomicrograph of the rostral rhinotheca. The fractured rostral portion of the beak was observed grossly (arrowheads). Extending from the rostral rhinotheca and effacing the underlying dermis and bone of the premaxilla and maxilla is a non-encapsulated, poorly demarcated, infiltrative neoplastic population with intermixed hemorrhage and areas of necrosis (asterisk). The neoplasm extends caudally with slight ventral compression of the rostral nasal cavity. Caudal to the nasal cavity, a nerve and ganglion are infiltrated by the neoplasm (arrow). NC, nasal cavity; Ce, cere. H&E stain. Bar = 2 mm. (B) The poorly demarcated, non-encapsulated, infiltrative neoplasm consists of densely cellular interweaving streams of well-differentiated spindle cells supported by minimal fibrovascular stroma. H&E stain. Bar = 60 mum. (C) The neoplastic spindle cells infiltrate into the medullary cavity of the bone with thinning and loss of the bony trabeculae. Occasional small fragments of necrotic bone are embedded within the neoplastic population and surrounded by macrophages and several multinucleated cells. The remaining trabeculae adjacent to the neoplasm often have scalloped edges with increased numbers of osteoclasts in Howship's lacunae, consistent with bone resorption/osteolysis. H&E stain. Bar size = 200 mum. (D) The nerve and ganglion just caudal to the nasal turbinates are infiltrated by a similar population of neoplastic spindle cells. H&E stain. Bar size = 200 mum.
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case_images: PMC10739488_01_fvets-10-1309185-g002.jpg
case_images: fig2
case_images: Histologic examination of the rostral portion of the upper beak revealed a poorly demarcated, non-encapsulated neoplasm infiltrating the dermis and bones of the premaxilla and maxilla while slightly compressing the rostral nasal cavity (Figure 2A). This neoplasm was composed of densely cellular interweaving streams of spindle cells supported by minimal fibrovascular stroma (Figure 2B). Anisocytosis and anisokaryosis were mild to moderate with 233 mitotic figures in 10400X fields (2.37 mm2). Occasional small fragments of necrotic bone were embedded within the neoplastic population and surrounded by macrophages and several multinucleated cells (osteoclasts and multinucleated giant cells) (Figure 2C). A similar population of neoplastic spindle cells infiltrated the trigeminal nerve and ganglion just caudal to the nasal turbinates (Figure 2D) as well as the optic nerve of one eye.
case_images: Immunohistochemistry panel on a beak leiomyosarcoma in the rostral rhinotheca of a 2-year-old male budgerigar. (A) Neoplastic cells had strong cytoplasmic immunolabeling for alpha-smooth muscle actin IHC. Bar size = 200 mum. (B) Neoplastic cells lacked immunolabeling for S-100 IHC. Bar size = 200 mum. (C) Neoplastic cells lack CK AE1/AE3 cytoplasmic immunolabeling (asterisk), normal epithelium is present as internal positive control (arrowhead). Bar size = 200 mum. (D,E) PNL-2 and Melan-A immunolabeling was absent in neoplastic cells. Bar size = 200 mum.
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case_images: PMC10739488_01_fvets-10-1309185-g003.jpg
case_images: fig3
case_images: Approximately 80% of the neoplastic cells exhibited strong cytoplasmic immunolabeling for alpha-SMA (Figure 3A) but lacked immunolabeling for S100, CK AE1/AE3, PNL2 and Melan-A (Figures 3B-E).