JPC SYSTEMIC PATHOLOGY
SPECIAL SENSES
May 2018
S-N06

Signalment (JPC # 2241434):  Cocker spaniel

HISTORY:  Tissue from a cocker spaniel with a long-standing history of otitis externa

HISTOPATHOLOGIC DESCRIPTION:  Slide S-N06a:  Glabrous skin, ear canal: Expanding the dermis, and elevating the overlying, hyperplastic epidermis, is an unencapsulated, well-circumscribed, moderately-cellular, polypoid neoplasm composed of cuboidal cells lining variably ectatic to cystic tubules, occasionally piling up to form multiple layers and papillary projections, supported by a moderate fibrovascular stroma. Neoplastic cells have indistinct cell borders, moderate amounts of eosinophilic granular cytoplasm, and round to oval nuclei with finely-stippled chromatin and one distinct nucleolus. Mitoses average 1 per 10 HPF. Diffusely, lumina of tubules are filled with pale homogeneous eosinophilic to gray-brown material (cerumen), few sloughed epithelial cells, macrophages, degenerate neutrophils and necrotic debris. Multifocally, there are few scattered lymphocytes, plasma cells, and macrophages that often contain intracytoplasmic brown material (cerumen). Diffusely, the epidermis is hyperplastic with acanthosis, occasional rete ridges and mild orthokeratotic hyperkeratosis. There is multifocal epidermal erosion and ulceration.

MORPHOLOGIC DIAGNOSIS:  Glabrous skin, ear canal:  Ceruminous gland adenoma, cocker spaniel, canine.

Signalment (JPC #1416286):  Cat

HISTORY:  Both ear canals contained variably sized nodules projecting from the pinna and occluding the canal.  The nodules were white to dark blue and firm.

HISTOPATHOLOGIC DESCRIPTION:  Slide S-N06b:  Haired skin, ear canal: Expanding the dermis, focally distorting the auricular cartilage, and elevating the hyperplastic, ulcerated epidermis, is an unencapsulated, poorly-circumscribed, infiltrative, densely-cellular neoplasm composed of polygonal cells arranged in nests, tubules and acini with multifocal luminal papillary ingrowths supported by a moderate fibrovascular stroma.  Neoplastic cells have variably distinct cell borders, moderate amounts of finely granular, eosinophilic, often vacuolated cytoplasm, and irregularly round to oval, occasionally vesiculate, nuclei with finely stippled chromatin and 1-2 magenta nucleoli.  There is moderate anisokaryosis and anisocytosis.  Mitoses average 2 per HPF.  Focally within the subcutis, a vessel contains a nest of neoplastic cells surrounded by fibrin.  The stroma contains multifocal aggregates of many lymphocytes, fewer plasma cells, neutrophils, and macrophages that are often laden with brown).  material (cerumen Adjacent ceruminous glands are ectatic, lined by attenuated cuboidal cells and are variably filled with abundant brown to eosinophilic secretory product (cerumen), necrotic debris, sloughed epithelial cells, macrophages, degenerate neutrophils and occasionally acicular cholesterol clefts.  Multifocally, sebaceous glands are mildly hyperplastic.  Diffusely, the epidermis overlying the neoplasm is hyperplastic, with acanthosis and rete ridge formation.  There is multifocal mild orthokeratotic hyperkeratosis and epidermal ulceration and erosion.

MORPHOLOGIC DIAGNOSIS:  Haired skin, ear canal: Ceruminous gland carcinoma, breed unspecified, feline.

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. De Lorenzi D, Bonfanti U, Masserdotti C, et al. Fine-needle biopsy of external ear canal masses in the cat: cytologic results and histologic correlations in 27 cases. Vet Clin Pathol. 2005:34(2):100-5.
  2. Drew SJ, Perpinan D, et al. Concurrent transitional meningioma and ceruminous gland adenocarcinoma in a Scottish wildcat hybrid. J Comp Pathol. 2016; 154:253-257.
  3. Goldschmidt MH, Goldschmidt KH. Epithelial and melanocytic tumors of the skin. In: Meuten DJ, ed. Tumors in Domestic Animals. 5th ed. Iowa State Press: Ames, IA, 2017:115, 119-120.
  4. Moisan PG, Watson GL. Ceruminous gland tumors in dogs and cats: a review of 124 cases. J Am Anim Hosp Assoc. 1996:32(5)448-452.
  5. Njaa BL. Tumors of the ear. In: Meuten DJ, ed. Tumors in Domestic Animals. 5th ed. Iowa State Press: Ames, IA, 2017:935-936.
  6. Njaa BL. The ear. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO:Elsevier-Mosby; 2017:1249-1250.
  7. Wilcock BP, Njaa BL. Special senses. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St. Louis, MO: Elsevier Limited; 2016:507-508.


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