The earlier biopsies were performed under local anesthesia and the second biopsy was performed under general anesthesia. The patient was referred to Seattle Children's Hospital for further evaluation and treatment.
The histological diagnosis was read by Dr. Thomas Morton, University of Washington, Oral Pathology Biopsy Service and Dr. Kathy Patterson, Seattle Children's Hospital.
Histologic examination revealed ulcerated surface epithelium with underlying fibrous connective tissue infiltrated by small to medium blue cells with vesicular nuclei (Figure 2). The neoplastic cells are arranged in groups and strands separated by collagen fibers and small blood vessels (Figure 2). Mitotic figures and apoptotic cells are readily identifiable. The Immunohistochemistry staining shows diffusely positive nuclear MyoD staining (Figure 3) and positive staining with desmin (Figure 4).
Figure 2 Low power (x400) the H & E histology reveals an infiltrative neoplasm made up of small to medium blue cells with vesicular nuclei arranged in groups and strands separated by collagen fibers. Mitotic figures and apoptotic cells are common.
Figure 3 Higher power (x400) the Immunohistochemistry stain demonstrates small to medium sized neoplastic cells to be positive with antibodies to MyoD. The positive staining is nuclear.
Figure 4 Low power (x400) the Immunohistochemistry stain demonstrated small to medium sized neoplastic cells to be positive with Desmin.