JPC SYSTEMIC PATHOLOGY

INTEGUMENTARY SYSTEM

October 2016

I-N10 (NP)

 

SLIDE A
Signalment (JPC #1956324): Aged poodle

HISTORY: One of several small dermal masses        

HISTOPATHOLOGIC DESCRIPTION: Haired skin and subcutis (2 sections): Expanding the dermis, elevating the epidermis, and surrounding and widely separating adnexal structures is an unencapsulated, well circumscribed mass composed of multiple lobules.  These lobules surround and compress ectatic ducts (up to 1.5 mm) lined by keratinized stratified squamous epithelium.  Lobules are further divided into variably sized adenomeres composed of a peripheral layer of flattened to cuboidal epithelial cells with scant amounts of eosinophilic cytoplasm, round to oval nuclei with finely stippled chromatin with 1 to 2 distinct nucleoli (basaloid reserve cells), and a central area containing polygonal cells with abundant vacuolated cytoplasmic granules and similar round nuclei (sebaceous differentiation).  The mitotic rate is 1 per 10 HPF and confined to the basaloid reserve cells.  Within the remaining dermis are occasional mildly dilated apocrine glands and lymphatics and collagen fibers are separated by clear space (edema).

MORPHOLOGIC DIAGNOSIS: Haired skin and subcutis:  Nodular sebaceous hyperplasia, focally extensive, poodle, canine.

SYNONYM:  Senile sebaceous hyperplasia

SLIDE B
Signalment (JPC #2147441): Age and breed unspecified dog  

HISTORY: None

HISTOPATHOLOGIC DESCRIPTION: Haired skin: Expanding the dermis and subcutis, elevating the overlying epidermis, and compressing adjacent adnexa is a 1.0 x 0.75 cm, partially encapsulated, well circumscribed, multilobulated neoplasm composed of polygonal cells arranged in islands and trabeculae supported by a fine fibrovascular stroma.  The majority of cells (up to 80%) are closely packed, with variably distinct borders, moderate amounts of granular eosinophilic cytoplasm and round to oval nuclei with finely stippled chromatin and 1 to 3 nucleoli (basaloid reserve cells).  The mitotic figures average1 per HPF and confined to the basaloid reserve cells.  Multifocally, there are moderate numbers of individual or small aggregates of polygonal cells with distinct cell borders, abundant vacuolated eosinophilic cytoplasm, centrally located round nuclei with stippled chromatin and up to 1 or 2 distinct nucleoli (sebaceous differentiation).  There is multifocal single cell necrosis, large cystic spaces (up to 1 x 3 mm) filled with eosinophilic cellular and karyorrhectic debris (cystic degeneration) and few foci of ductular differentiation.  Multifocal neoplastic cells and macrophages contain melanin.  Multifocally within the mass and in the adjacent dermis are small aggregates of lymphocytes and plasma cells.

MORPHOLOGIC DIAGNOSIS:  Haired skin and subcutis:  Sebaceous epithelioma, breed unspecified, canine.

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Mauldin EA, Peters-Kennedy J. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed, Philadelphia, PA: Elsevier Saunders; 2016:717-720.
  2. Sabattini S, Bassi P, Bettini G. Histopathological findings and proliferative activities of canine sebaceous gland tumors with a predominant reserve cell population, J Comp Path. 2015;152: 145-152.
  3. Bongiovanni L, Suter MM, Malatesta D, Ordinelli A, Ciccarelli A, Romanucci M, Brenners O, Salda LD. Nuclear survivin expression as a potential useful tool for the diagnosis of canine cutaneous sebaceous lesions. Vet Dermatol. 2012; 23: 394-e73.
  4. Goldschmidt MH, Hendrick MJ: Tumors of the skin and soft tissues. In: Tumors in Domestic Animals. 4th ed. Ames, IA: Iowa State Press; 2002:64-67.
  5. Gross TL, Ihrke PJ, Walder EJ. Dysplastic diseases of the adnexa. In: Gross TL, Ihrke PJ, Walder EJ, eds. Skin Diseases of the Dog and Cat. 2nd ed. Ames, IA: Blackwell Science Ltd; 2005:531-533.
  6. Gross TL, Ihrke PJ, Walder EJ. Sebaceous tumors. In: Gross TL, Ihrke PJ, Walder EJ, eds. Skin Diseases of the Dog and Cat. 2nd ed. Ames, IA: Blackwell Science Ltd; 2005:641-655.
  7. Hargis AM, Myers, S. The Integument. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier Mosby; 2016:1034.
  8. Scott DW, Miller WH, Griffin CE. Neoplastic and non-neoplastic tumors. In: Scott DW, Miller WH, Griffin CE eds. Small Animal Dermatology, 6th ed. Philadelphia, PA: WB Saunders Company; 2001:1270-1275.


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