[Immunohistochemical detection and ultrastructural features of solitary plasmacytoma of maxillary bone--case presentation].

Plasma cell neoplasm have been classified as multiple myeloma, solitary plasmacytoma and extramedullary plasmacytoma. The solitary plasmacytoma of maxilla is a rare condition. It is a single focus of myelomatous tissue with no dissemination to other parts of the skeleton. This paper presents a case of solitary plasmacytoma in the maxillary bone. Roentgenographic examination revealed a cystic-like osteolytic lesion over the left posterior portion of maxillary bone, invading maxillary sinus. The CT scan showed the tumor mass occupied the left maxillary sinus and lateral wall of the nasal cavity, protruding to the buccal side of the left face. The tumor cells were composed of densely packed round and polygonal cell structures which were scattered in relatively sparse stoma. The neoplastic cells have large, single eccentric nucleus, resembling typical plasma cells. The ultrastructural studies of tumor cells revealed numerous endoplasmic reticulum. There were arranged in a lamellar pattern, large numbers of mitochondria in perinuclear distribution and prominent Golgi complex. Nuclei showed patch condensation of chromatin and large nucleoli. The monoclonal staining (anti-Kappa and anti-IgG) of tumor cells by the peroxidase anti-peroxidase immunohistochemical technique, proved that the plasma cell lesion is neoplastic in nature. The tumor mass was eradicated by total resection, followed by X-ray radiation (4200 RADS). The patient is in good physical condition. There has been no clinical evidence of recurrence three years after surgery.