Endocrine Abstracts

Introduction: Metastatic pituitary tumors are seen rarely and it is hard to differentiate them from the benign lesions of the gland. We have reported a case, with a known maxillary sinus tumor, detected to have a pituitary lesion coincidentally on PET-CT.

Case: 45 years old male patient with a known history of relapsed maxillary sinus tumor has been referred to our clinics because of the pituitary lesion detected to have increased FDG involvement on PET-CT examination. He was operated for the maxillary sinus tumor 35 years ago and had the second operation last year because of the recurrence. Histopathological examination was reported as well-differentiated squamous cell carcinoma with perineural and lymphovascular invasion. There was a tissue defect on the right maxillary region, nose and the right eyelid in physical examination. Pitiutary lesion was metabolically active on PET-CT and SUV_max value was 11.7. We have demanded a pitiutary MRI and detected a 5.4×4.3 mm sized nodular pitiutary lesion on the right side of the gland, which was isointense on T1A and T2A images and with late contrast concentration on dynamic sequences. In laboratory examination, anterior pituitary functions are in normal ranges. There wasn’t any symptom or sign of diabetes insipidus. Tissue biopsy for the definitive diagnosis could not be performed because of the facial defect.

Conclusion: It is difficult to differentiate metastatic lesions from the benign lesions of the pituitary gland. Most of the metastatic lesions are asymptomatic although presences of diabetes insipidus or ophthalmoplegia are suspicious for metastasis. Also, there isn’t any specific radiologic sign for metastatic lesions. In our case because of the lesion being metabolically active on PET-CT with a high SUV_max value, isointense appearance on MRI and a history of maxillary sinus malignancy made us suspect pituitary metastasis.