Lesions of the Petrous Ridge: Metastatic pituitary carcinoma with discussion of differential diagnosis

OBJECTIVE: To discuss the differential diagnosis of petrous ridge lesions based on a rare case of metastatic pituitary carcinoma. PATIENT: A 41-year-old man with a past medical history of pituitary adenoma and hypopituitarism presented with imbalance and vertigo. Imaging showed a mass eroding the left posterior petrous face. INTERVENTION: Transtemporal, transmastoid approach for complete resection of tumor. MAIN OUTCOME MEASURES: Surgical pathology and imaging studies. RESULTS: Surgical pathology revealed metastatic pituitary carcinoma. The patient has been followed at our institution for 28 months postoperatively without evidence of recurrence. CONCLUSION: Lesions of the petrous ridge are rare. The wide differential diagnosis includes endolympatic sac tumor, meningioma, jugulotympanic paraganglioma, myeloma, and metastasis. The clinician must take into account unique imaging features on CT and MRI, and final diagnosis often requires pathologic analysis.