11/16/2010 Case 2: Pituitary adenoma, atypical, invasive, expressing prolactin

Presented by: Dr. Zeng and Dr. Rao - Kings County Hospital

Clinical History:

A 76-year-old woman presented with a one week history of severe headache. She had postmenopausal bleeding and unsteady gait for the past year. She did not have any visual changes, weakness, sensory changes or bowel/bladder incontinence. Brian MRI showed a 5.3 x 5.5 x 3.2 cm mass with extensive bony erosion of the clivus and adjacent skull base bones. The mass was seen in the sphenoid sinus and ethmoid sinus. The radiologists' differential diagnosis was giant cell tumor, plasmacytoma, chordoma, and metastastic neoplasm.  There was no sellar involvement, as per the neurosurgeon and the ENT surgeon.  A frozen section was read as "malignant." 

Sections showed a tumor of uniform cells with rounded nuclei and moderate amounts of cytoplasm arranged in sheets and nests.  Mitoses were easily found in some areas.  Proffered differential diagnoses included PNET, rhabdoid tumor, neuroblastoma, sinonasal undifferentiated carcinoma, small cell neuroendocrine tumor and olfactory neuroblastoma.  Review of the x-ray studies showed that the tumor was indeed in the sella and pituitary adenoma was suggested.  The tumor was strongly positive for AE1/3, CAM5.2 and synaptophysin and focally positive for chromogranin but it was negative for CD56, S100, EMA and TTF1.  The patient had noticed breast heaviness for weeks and prolactin was >200 (normal <20 ng/ml).  Other pituitary hormones were within normal limits  Prolactin was strongly and diffusely positive.  Ki-67 showed 12% nuclear labeling and p53 was positive. 

Diagnostic Notes:


The diagnosis was Pituitary adenoma, atypical, invasive, expressing prolactin.  The diagnosis of pituitary carcinoma is be made when there are intracranial metastasis discontinuous to the original tumor or distant extracranial metastases. 

A search for metastasis was suggested due to the numerous mitoses and high Ki-67 index.  Metastatic work-up was negative and radiotherapy was given. 


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