[1247] Ectopic Pituitary Adenoma (EPA): A Clinicopathologic Study of 40 Cases

A Ranade, EJ Rushing, CS Heffess, DP Kowalski, CE Iacob, G Groisman, DK Heffner, BM Wenig. Beth Israel Medical Center, St-Luke's and Roosevelt Hospitals, New York; Armed Forces Institute of Pathology, Washington; Yale University, New Haven; New York Eye & Ear Infirmary, New York; Hillel Yaffe Medical Center, Hadera, Israel

Background: EPA may arise in various upper aerodigestive tract sites from remnants of Rathke's pouch. In these locations, misdiagnosis with other neuroendocrine/neuroectodermal tumors (eg, paraganglioma, olfactory neuroblastoma, neuroendocrine carcinoma) or with malignant epithelial neoplasms may occur.
Design: 40 cases of EPA were identified from our files. Clinical records were available in all cases; material (blocks, slides) were variably available for immunohistochemical (IHC) staining. IHC antigenic profile included staining for cytokeratins (AE1/AE3, CAM5.2), chromogranin, synaptophysin, CD56, S100 protein, neuron specific enolase, MIB-1 (Ki67) and pituitary hormones, including adrenocorticotropic hormone, growth hormone, prolactin, follicle stimulating hormone, luteinizing hormone and thyroid stimulating hormone. A requirement for inclusion was radiologic imaging showing the sella turcica/pituitary gland to be uninvolved by tumor.
Results: The patients included 24 males and 16 females ranging in age from 22-84 yrs (median, 51 yrs). Symptoms included airway obstruction, chronic sinusitis, epistaxis, visual field defects, CSF leakage, and headaches. The primary site of occurrence included the sphenoid sinus (n=27), nasopharynx (n=5), nasal cavity (n=4) and ethmoid sinus (n=4). The tumors were submucosal with solid, organoid, and trabecular growth patterns, fibrovascular stroma composed of bland cells with round nuclei, dispersed chromatin and granular eosinophilic cytoplasm. Pleomorphism, necrosis and increased mitotic activity were not seen. IHC staining was present for neuroendocrine markers (chromogranin, synaptophysin and/or CD56) in 90% and cytokeratin in 71% of cases. Reactivity with pituitary hormones included 50% reactive for 2 or more hormones (plurihormonal PA), 39% reactive for a single hormone and 11% non-reactive (null cell). MIB-1 staining in 18 cases showed a low proliferation rate (less than 1%). Surgery is the treatment of choice and often proves curative without recurrent or progressive tumor.
Conclusions: EPA primarily arises in the sphenoid sinus with characteristic light microscopic and IHC findings. Misdiagnosis and unwarranted therapy occurs due to misinterpretation of the light microscopic and IHC correlative findings.
Category: Head & Neck

Tuesday, March 23, 2010 11:15 AM

Platform Session: Section G, Tuesday Morning


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