title: Prolactin-producing pituitary adenoma with incomplete neuronal transformation: an intermediate adenoma-neuronal tumor.
abstract: We present a unique case of a prolactin (PRL)-producing pituitary adenoma showing incomplete neuronal differentiation without ganglion cells. A 27-year-old man presented with nausea, headaches, and instability over the last 2 months. Clinical examination revealed obesity with no other endocrinological signs. His serum PRL levels were slightly elevated (38 ng/ml), whereas concentrations of the other adenohypophysial hormones were within normal range. Histology revealed an unusual pituitary adenoma containing many hypocellular areas with fibrillar appearance. The sizable tumor cells were polyhedral or elongated harboring an ovoid, vesicular nucleus with prominent nucleolus, lacking, however, the typical features of ganglion cells. By immunohistochemistry, many adenoma cells were positive for PRL. Immunostain for neurofilament protein revealed variable amounts of fibrils dispersed throughout the stroma, mostly in the hypocellular areas. In addition, neurofilament protein and chromogranin were strongly reactive in approximately 15% of the tumor cell population, whereas reactivity for synaptophysin was uniform throughout the tumor. These findings led to the conclusion that part of the tumor-cell population expressed a hybrid immunoprofile of adenoma-neuronal cell. Our case is the first PRL-producing pituitary adenoma showing incomplete neuronal differentiation lacking mature ganglion cells.
authors.affiliation: Departments of Pathology, 1G. Gennimatas General Hospital of Athens, KOFKA Building, 1st Floor, 154 Messogion Ave., 115 27, Athens, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Thodou
authors.forename: George
authors.initials: G
authors.lastname: Kontogeorgos
authors.forename: Eva
authors.initials: E
authors.lastname: Horvath
authors.forename: Kalman
authors.initials: K
authors.lastname: Kovacs
mesh_terms: D000236:Adenoma / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D000328:Adult; D002454:Cell Differentiation / Q000502:physiology; D002864:Chromogranins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009447:Neuroblastoma / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D009454:Neurofibrils / Q000378:metabolism / Q000473:pathology; D016900:Neurofilament Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D011388:Prolactin / Q000378:metabolism*; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D002864:Chromogranins; D016900:Neurofilament Proteins; D016708:Synaptophysin; D011388:Prolactin