Department of Pathology, University of Oklahoma Health Sciences Center

NeuroTest Sample Question #58 Next question Previous question

Answer: D (Pituitary adenoma)  Level of difficulty: 2 NeuroTest NeuroLearn NeuroHelp

Discussion: 

• Pathology of the case: The cells apperar monotonous. The monotonous appearance is, in fact, best appreciated under medium magnification [Click here to see medium magnification]. Many of the nuclei are naked. This is resulted from poor preservation of the delicate cytoplasm with the smearing process. A touch preparation may show better preservation. The nuclei have a "salt and pepper" look suggestive of neuroendocrine tumors. The background is clean and free of necrosis. There is no "crush artifact" of nuclei that would lead to elongated long deep blue processes. The amount of cytoplasm is minimal to moderate and appear slightly granular. These features are characteristic of pituitary adenoma.  [Click here to see a related case] Oncocytic changes occur quite often in pituitary adenoma. The oncocytic cells will have a moderate to high volume of eosinophilic, coarsely granular cytoplasm and, often, increased nuclear atypia. The oncocytic changes may not be uniformly seen in all cells and is partly due to poor preservation of the cytoplasm on smears. [Click here to see oncocytic changes, illustrated by arrow]. On frozen sections, adenomas with oncocytic changes often have large volume of cytoplasm. The increased nuclear atypia in oncocytic cells add in another factor for confusion. [Click here to see an oncocytoma in frozen section] [Click here to see an oncocytoma on permanent section]
• Meningioma: One of the salient feature of meningioma in cytologic preparation is preservation of cytoplasm. Most of the cells in this picture are, on the contrary, naked. Meningioma have open nuclei but not "salt and pepper" nuclei.  Meningioma should not be seriously considered.
• Seminoma: After the pineal region, the sellar-suprasellar region is the most common site for seminoma and this diagnosis must be entertained. However, seminoma is typically associated with two population of cells- the large seminoma cells with large, bizarre nuclei and prominent nucleoli and the lymphocytes which are significantly smaller. This is not the case here. There is only one monotonous population with no large nuclei or prominent nucleoli. Seminoma cells also have a respectable volume of cytoplasm. The cells here have only minimal.
• Metastatic adenocarcinoma: Metastatic neoplasm in this region is a rather uncommon event. Metastatic adenocarcinoma usually have more pleomorphism and prominent nucleoli in comparison to pituitary adenoma. Metastatic adenocarcinoma usually have more cytoplasm and the cells tend to adhere together in cluster. Necrosis is often present. Some adenocarcinoma, however, can have bland morphology. Three of the notable offenders are metastatic clear cell carcinoma of the kidney (renal cell carcinoma), metastatic adenocarcinoma of mammary origin, and of prostatic origin. [Click here to see a metastatic breast carcinoma to the cerebellum]

Comment: KarMing-Fung@ouhsc.edu