Follicular stem cell carcinoma: histologic, immunohistochemical, ultrastructural, and clinical characterization in 30 dogs.
Diagnostic records of 30 primary and one metastatic follicular stem cell carcinomas in 30 dogs were reviewed. Neoplastic cells had a clear cytoplasm and formed lobules and nests surrounded by a basement membrane. Trichoepitheliomatous and apocrine differentiations were noted in 22 of 30 (73%) and 21 of 30 (70%) primary tumors, respectively. Glycogen was present in 20 of 20 (100%) tumors tested, suggesting tricholemmal differentiation. Antibodies against AE1/AE3 cytokeratin, vimentin, and melanA/MART1 stained 29 of 30 (97%), 29 of 30 (97%), and 12 of 27 (44%) primary tumors, respectively. Small amounts of melanin were identified in 14 primary tumors, either on the hematoxylin and eosin-stained section (n = 6), or on the Fontana-stained section (n = 8 of 14). Ultrastructural features of neoplastic cells included cell junction complexes, swollen mitochondria, neuroendocrine-like granules, and intracytoplasmic non-membrane-bound accumulation of proteinaceous material. Features of this neoplasm are consistent with a follicular stem cell origin. Follow-up information was available for eight dogs. Metastases developed in the draining lymph node at the time of excision of the primary tumor (n = 1) or subsequently (n = 3).
Mikaelian
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IDEXX Veterinary Services, West Sacramento, CA, USA. imikaeli@jax.org
Wong
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D000818:Animals; D002280:Basal Cell Carcinoma / Q000473:pathology* / Q000648:ultrastructure / Q000662:veterinary*; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary*; D008297:Male; D008854:Microscopy, Electron; D012189:Retrospective Studies