Differential Diagnosis and Management of a Pituitary Mass with Renal Cell Carcinoma
A 40-year-old woman presented with mild headache. Three years prior, she had undergone a left radical nephrectomy for renal cell carcinoma. Video-assisted thoracic surgery was performed for metastatic lymph node excision and left lower lobe superior segmentectomy. Additional procedures included the excision of a retroperitoneal lymph node metastasis and thoracotomy for lymph node dissection along the descending aorta. She received chemotherapy for multiple metastases, including the adrenal gland, psoas muscle and mediastinum. During the follow-up after chemotherapy, she complained of intermittent headache. Magnetic resonance (MR) imaging demonstrated a 13 mm sellar mass with suprasellar extension without optic nerve compression (). The pituitary stalk was deviated to the left side. An endocrinological evaluation revealed hyperprolactinemia as follows : serum prolactin, 89.5 ng/mL [reference range (RR) : 0-25 ng/mL]; free T4, 0.75 ng/dL (RR : 0.70-1.80 ng/dL); TSH, 1.73 uIU/mL (RR : 0.4-4.1 uIU/m); ACTH at 8 am, 52 pg/mL (RR : 0-60 pg/mL); Cortisol at 8 am, 7.2 ug/dL (RR : 5-25 ug/dL); LH, 6.7 mIU (RR : 1-12 mIU); and FSH, 11.5 mIU (RR : 2-13 mIU). 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) showed no uptake in the sellar area, and increased uptake in metastatic lesions in other sites (). She did not complain of the visual symptoms, and Goldmann perimetry revealed no visual field defects. A careful history revealed that she had experienced galactorrhea and amenorrhea, which continued for 5 months and resolved without management 9 years ago prior to her current presentation. With these clinical backgrounds, a presumptive diagnosis of pituitary adenoma was made and regular follow-up was recommended because of the relatively rare incidence of pituitary metastasis.\nSix months after the first visit, her vision worsened. Snellen visual acuity without correction at a 5 m distance in 200 lux of light showed a marked decrease in visual acuity from 1.0/1.0 to 1.0/0.4. Goldmann perimetry revealed superior temporal quadrantanopsia of the left eye. The follow-up MR imaging showed that the mass from 13 mm to 23 mm, and compression of the optic apparatus was observed (). The cocktail test showed hyperprolacinemia (prolactin, 74.4 ng/mL) and hypocortisolism (peak cortisol, 11.9 ug/dL). The other pituitary axes were intact, and there were no symptoms suggesting diabetes insipidus.\nThe patient underwent trans-sphenoid surgery to obtain a pathologic diagnosis and decompress the optic apparatus. The sellar floor was very thin and showed a mottled appearance. The tumor was gray and hypervascular (). Its hard consistency and the distinct demarcation helped to easily dissect it from the pituitary gland and cavernous sinus. However, we removed parts of the diaphragma sellae with the superior surface of the tumor because the tumor was strongly adhered to it. The tumor was completely removed in a piecemeal fashion, and the pathology was compatible with renal cell carcinoma (). The post-operative course was uneventful and her vision recovered to its previous original state within one month after surgery. The clinical and radiological follow-up has been continued without adjuvant therapy and hormone replacement.