Objective and importance: Giant-cell tumors (GCTs) are primary bone tumors that involve long bones in 75 to 90% of patients. They seldom develop in the cranium and are very rare in patients older than 60 years of age. A GCT rarely occurs with Paget's disease; when it does, however, it is most commonly associated with the polyostotic form and tends to involve the craniofacial bones. Pagetic GCTs are less aggressive than GCTs that are not associated with Paget's disease.
Clinical presentation: We report the case of an 81-year-old woman with a painless left parietal mass and asymptomatic monostotic parietal Paget's disease.
Intervention: Surgical resection was performed, and histological examination of the lesion demonstrated Paget's disease with a malignant GCT. An incidental, low-grade, small-cell lymphocytic lymphoma also was noted. The patient experienced local recurrence of the malignant GCT and eventually died after developing pulmonary metastases of the malignant GCT.
Conclusion: This case is the first reported example of a patient with a malignant GCT of the cranium associated with monostotic Paget's disease. It provides evidence that not all pagetic GCTs in the cranium are benign, as has been reported.