Uterine mast cell tumor: a clinical and cytohistopathological study

Abstract

Background: Mast cells are one of the characteristic factors in angiogenesis, growth, and metastatic spread of tumors. Further studies are suggested to determine the type of these cells which might be useful in the assessment of biological nature of the tumor and its future treatment modality. Few studies have evaluated mast cell infiltration in visceral tumors, especially uterine tumors.

Case presentation: In this study, age, sex, death rate, and histologic patterns were in agreement with those of previous reports on canine mast cell tumors. Cytopathology assays are widely used to prognosticate canine uterine mast cell tumors (MCT). There is limited information about these prognostic assays used on MCT that arise in the uterine. The anisocytosis and anisocytosis and giant cells were present in the tumor. Furthermore, the tumor had nuclear atypia with scattered multinucleated cells and prominent nucleoli and tumor were classified as poorly granulated. Under microscopic examination, we observed diffuse infiltration and proliferation of tumor cells from the uterine different area and the infiltrative characteristics and distribution patterns of neoplastic cells were observed. This tumor consisted of sheets and cords of uniform round cells with discrete cytoplasmic margins. Microscopically, the neoplastic masses were poorly-demarcated and lacked capsules and tumor cell usually showed a distinct cell boundary. Nevertheless, the neoplastic cells were located between collagen bundles forming small clusters and sheets and had large, centrally located, round to ovoid nuclei. In addition, eosinophils were scattered among the mast cells at the periphery of the masses. The presence of eosinophils and the observation, at high magnification, of cells with cytoplasmic metachromatic granules.

Conclusion: Based on these findings, a diagnosis of poorly-differentiated mast cell tumor was made and data histologic grading was available for tumor. Neoplasm was poorly differentiated or gradeIII.

Figure 1

Fine-needle aspirate smear of a mast cell tumor, uterus; dog. There are many large round cells with centrally placed round nuclei, Mastocytic pleomorphic types: Moderate to marked pleomorphism and abundant infiltrate of small lymphocytes and at high magnification, nuclei are large and eccentric and have variable chromatin patterns, and nucleoli are generally prominent. H&E.

Figure 2

Histopathology of a tumoral mass from the uterine of the dog. Neoplastic mast cells form dense sheets within the intraparenchymal uterus. Hematoxylin and eosin stain, ×200. Bar = 100 μm.

Figure 3

Uterine mast cell tumor, dog. Pleomorphic, round to spindle cells containing a variably sized nucleus are observed. Infiltration of eosinophils is prominent together with mitotic figures. Hematoxylin and eosin, ×400. Bar =10 μm.

Figure 4

Photomicrograph of a poor-circumscribed canine uterus mast cell tumor. Mitotic index is recorded as the number of mitotic figures. Neoplastic mast cells are arranged as single cells, loose aggregates, and rows linearly arranged along collagen fibers, as supported by abundant collagenous stroma interspersed with eosinophils Hematoxylin and eosin, ×400. Bar =10 μm.

Figure 5

Uterine; dog; mast cell tumor. Note the tumor cells are numerous eosinophilic granulocytes that eosinophils are present at the periphery of the tumor cells that arranged in sheets within a scant pre-existing collagenous stroma and granular cytoplasm. Hematoxylin and eosin, ×600. Bar =10 μm.