Nasal Cavity Hyperplastic and Neoplastic - Pathology

()Map CARDIORESPIRATORY SYSTEM (Map) NASAL CAVITY

Fibrosarcoma in rhinarium of a cat (Image sourced from Bristol Biomed Image Archive with permission)

Lymphoma in nasal cavity (Image sourced from Bristol Biomed Image Archive with permission)

Nasal cavity carcinoma (Image sourced from Bristol Biomed Image Archive with permission)

Nasal neoplasia in general

• Majority are malignant, locally invasive but do not metastasise
• Usually pale, soft, fleshy or friable
• May be osteoma or osteosarcoma, chondroma or chondrosarcoma, fibroma or fibrosarcoma, myxoma or myxosarcoma, haemangioma or haemangiosarcoma, adenoma or adenocarcinoma

Adenocarcinoma

• Most common in dogs, also sheep
• Glandular acini in layer of cuboidal or columnar epithelium
• Often mucin filled acini

Transitional cell carcinoma

• Most common in dogs
• Thick stratified layer of cuboidal cells with distinct basement membrane
• Large growth may be separated by fibrovascular septa
• May contain microcysts that could be confused with adenocarcinoma above

Squamous cell carcinoma

• In cats they arise mainly from nasal vestibule
• In horses they originate mainly from maxillary sinus
• Most common nasal tumour
  • Serosanquineous or mucopurulent, odourous nasal discharge
• Tissue necrosis
• May cause airway obstruction or facial distortion

Olfactory neuroblastoma

• Rare, mainly occurs in cats
• Arises from ethmoturbinates in caudal region of nasal cavity
• May penetrate cribriform plate into cerebral cortex

Ethmoturbinate tumours (papillomas and adenocarcinomas)

• In horses and other species
• Multiple species may be affected on one premises
• Arising from olfactory cells are endemic in some parts of the world for unknown reason
• May be caused by a virus?

Progressive ethmoidal haematoma

• Slowly expanding non-neoplastic mass of horses
• Originates from submucosa of ethmoidal labyrinth
• Either from nasal or sinusal portion of ethmoid labyrinth
• Unilateral, can extend to nostrils or choanae
• Rarely elsewhere in sinuses
• Expands to nasal cavity, paranasal sinuses, nasopharynx causing destruction of tissue
• Micro - haemorrhage, calcification of connective tissue fibres
• Aspergillus spp. may be present on the lesion
• May cause epistaxis
• Can recur after surgical excision
• May arise subsequently to chronic inflammation

Nasal polyps

• Polypoid thickening of the inflamed nasal musosa, hyperplastic epithelium
• Pinkish, often pedunculated masses, round, often large and multiple proturberences into the nasal meatus
• Can arise subsequently to chronic inflammation
• Old polyps may becoma fibrous
• May recur when excised
• Necessary to distinguish from neoplasia
• Common in cats, less often in dogs, also horses and sheep
• Also see Progressive haematoma of horses and Nasopharyngeal polyps of cats

Nasal and paranasal sinus cysts

• Mimic infection or neoplasms
• Expand and destroy surrounding tissue
• Epithelial capsule with haemorrhagic or yellow fluid
• Do not tend to recur after surgery