EXTRAMEDULLARY PLASMACYTOMA OF THE SKULL BASE DEVELOPING INTO MULTIPLE MYELOMA: A CASE REPORT

Introduction: An extramedullary plasmacytoma (EMP) is a discrete, solitary mass of neoplastic monoclonal plasma cells which is thought to arise from soft tissue. It is a rare lesion to diagnose. 80-90% of tumors develop in the head and neck area, especially the upper airways and paranasal sinuses. When the skull is involved most occur in the calvarium and only a few cases have been described in the skull base.Materials and Methods: A 29-year-old woman complained of frontal headache, diplopia and vision loss of the right eye. Cranial CT revealed a 4/4cm-sized mass engaging the sphenoidal sinus, the clivus and the anterior cranial fossa and an extradural osteolytic lesion in the left parietal region with soft tissue component and bone destruction. Total extirpation of the tumour was performed and further examination concluded extramedullary plasmacytoma. Two months after the end of the local radiotherapy treatment she complained of nausea, vomiting, loss of appetite and severe abdominal and lumbar pain. Clinical examination showed progression of the EMP to multiple myeloma. Due to the aggressive evolution of the disease the patient died shortly after the first course of the systemic polychemotherapy treatment.Results: EMP represents 3% of all plasma cell neoplasms. The median age of patients is 55 years and 75% involve males. It progresses to multiple myeloma in 11-30% of cases at 10 years. Extramedullary plasmacytoma of the skull (EPS) is very rare and only 35 cases have been reported. They present more commonly in female patients (89%) and the cranial base location is the strongest predictor of the development of multiple myeloma.Conclusion: This report presents a case of an uncommon tumour in a rare location in an unexpectedly young patient. Its development supports the data from the little known cases for rapid progression of the EMP of the skull base to multiple myeloma and a lethal outcome soon after