History and admission findings: A 59-year-old woman was diagnosed as having solitary bone plasmacytoma of the sternum which was resected. Five month later she presented with a pathological fracture of the clavicle. On examination she had a ptosis and an ophthalmoplegia.
Investigations: A mass in the clivus extending into the left sphenoid sinus as well as multiple osteolytic lesions in the skull were shown by cranial MRI. Skeletal survey showed multiple osteolytic lesions. Laboratory test did not show any specific abnormalities.
Diagnosis, treatment and course: The biopsy taken from the mass at the sphenoid sinus demonstrated plasmacytoma. The diagnosis of multiple myeloma was based on the histological evidence of plasmacytoma and the occurrence of multiple lytic bone lesions although no infiltration of bone marrow and none of the specific laboratory findings were present. The patient underwent local radiotherapy with 30 Gy followed by systemic chemotherapy. The symptoms regressed completely under this therapy.
Conclusion: Various cranial nerve syndromes such as the superior orbital fissure syndrome are most often caused by tumors at the skull base. Knowledge of the histological entity is essential for the correct diagnosis and the appropriate therapy because rare tumors like multiple myeloma may also cause such syndromes.