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Cutaneous mast cell tumor (Mastocytoma): Cyto- histopathological and haematological investigations

Ehsan Hosseini1, Behnam Pedram2, Ali Mohammad Bahrami1*, Mohammad Hossein Jaberi Moghaddam3, Javad Javanbakht4, Fatemeh Emami Ghomi5, Najme Jaberi Moghaddam6, Mobin Koohestani3 and Radmehr Shafiee7

Author Affiliations

1 Faculty of Para Veterinary Medicine, Ilam University, Ilam, Iran

2 Department of Pathobiology, Susangerd Branch, Islamic Azad University, Susangerd, Iran

3 Graduate, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

4 Department of Pathobiology, Faculty of Veterinary Medicine, Tehran University, Tehran, Iran

5 Graduate, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran

6 MSc, Clinical Biochemistry, Tarbiat Modares University, Tehran, Iran

7 Graduate, Faculty of Veterinary Medicine, Tehran University, Tehran, Iran

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Diagnostic Pathology 2014, 9:9  doi:10.1186/1746-1596-9-9

Published: 20 January 2014


Cutaneous mast cell tumours (MCTs) are the most common skin tumours in dogs. Due to the prevalence of canine MCTs and the variable biologic behavior of this disease, accurate prognostication and a thorough understanding of MCT biology are critical for the treatment of this disease. A cytologic diagnosis of mast cell tumor with evidence of prior hemorrhage was made, and the masses were surgically removed. Cytological evaluation of fine-needle aspirates from the cutaneous mass from the axillary comprised many well-differentiated, highly granulated mast cells with moderate numbers of eosinophils. Nuclei were varied in size and shape with high nuclear’to’cytoplasmic ratio, prominent nucleoli, marked atypical and mitotic figures. Microscopically, mass consisted of sheets of neoplastic round cells that formed nonencapsulated nodules in the dermis and infiltrated into the adjacent dermal collagen, and also there was diffuse subcutis invasion of round to pleomorphic tumor cells. Tumor cells had moderate to abundant cytoplasm, round to ovoid nuclei with scattered chromatin, and mitotic figures. In this tumor, cytoplasmic granules showed atypical metachromasia. In addition, eosinophils were scattered among the mast cells at the periphery of the nodules. The presence of eosinophils and the observation, at high magnification, of cells with cytoplasmic metachromatic granules. Invasion of the deep subcutaneous fat or cutaneous muscles were a common feature of grade III tumour. Finally, a diagnosis of grade III cutaneous mast cell tumor was made.

Virtual slides

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Cytology; Pathology; Dog; Mast cell tumor; Grading