RANIOPHARYNGIOMAS are uncommon tumors with distinctive histological features and a pronounced tendency to invade locally and to recur following therapy. 5,14,16 Two variants of craniopharyngioma, with differing clinical and morphological features, have been described. The adamantinomatous craniopharyngioma is composed of a complex mixture of adamantinoma-like epithelium, “wet” keratin, microcalcifications, necrotic debris, fibrosis, and micro- or macrocysts. In contrast, papillary craniopharyngiomas form papillae composed of mature squamous epithelium and are unaccompanied by fibrocalcific and degenerative changes. 8 Whereas ada- mantinomatous tumors occur at all ages, predominating during childhood and early adolescence, papillary cra- niopharyngiomas have been reported only in adults. Furthermore, the papillary forms are reportedly less prone to recurrence. 1 Few reports of papillary craniopharyngioma have been published; of these, all but one are based on small num- bers of cases. A detailed account of the clinical, endo- crinological, radiographic, and operative features of papil- lary craniopharyngioma; its response to therapy; and the morphological features that distinguish it from other cys- tic suprasellar lesions has not been published. To address these issues, we describe the Mayo Clinic’s experience with 48 patients having papillary craniopharyngioma. Clinical Material and Methods The Mayo Clinic Tissue Registry files dating from 1910 to 1994 were reviewed as were microsections of all tumors surgically resected from the sellar region (other than pituitary adenomas). A diagnosis of papillary cranio- pharyngioma was made when the epithelial component of J Neurosurg 83:206–214, 1995 206 Papillary craniopharyngioma: a clinicopathological study of 48 cases THOMAS B. CROTTY , M.D., BERND W. SCHEITHAUER, M.D., WILLIAM F. YOUNG, JR., M.D., DUDLEY H. DAVIS, M.D., EDWARD G. SHAW, M.D., GARY M. MILLER, M.D., AND PETER C. BURGER, M.D. Divisions of Anatomic Pathology, Endocrinology/Metabolism and Internal Medicine, and Radiation Oncology, and the Departments of Neurologic Surgery and Diagnostic Radiology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota; and the Department of Pathology, The Johns Hopkins Hospital, Baltimore, Maryland  Two distinct clinicopathological variants of craniopharyngioma exist: the classic adamantinomatous type and a recent- ly described papillary form that predominates in adults and reportedly behaves in a less aggressive manner. The present study describes the clinicopathological features of 48 patients with papillary craniopharyngioma treated at the Mayo Clinic between 1910 and 1994. An additional four tumors were found to have histological features of both adamantinomatous and papillary craniopharyngioma. Whereas adamantinomatous tumors typically occur in adolescent patients, the mean age of the 48 patients (23 males and 25 females) with papillary craniopharyngioma was 44.7 years (range 10 to 74 years). Presenting clinical features included visual impairment (84%), headache (68%), and pituitary insufficiency (anterior 42%; posterior 27%). Preoperative computerized tomography (CT) and magnetic resonance (MR) imaging in 17 patients typi- cally revealed a noncalcified, partially cystic mass that enhanced peripherally and contained mural nodules (67%). Many (41%) of the lesions involved or extended into the third ventricle on imaging. At first surgery, gross total tumor removal was achieved in 17 patients (36%) and subtotal resection in 30 patients (64%) in whom tumor resection was attempted. Tumor recurrence was noted in two patients who underwent gross total removal. Tumor-free survival rates of 100% and 78% were obtained in patients who underwent gross total and subtotal resection at initial surgery, respectively. Postoperative radiation therapy was beneficial to patients having undergone a subtotal resection, with an increase in tumor- free survival from 26% to 86%. Aside from well-documented morphological distinctions, papillary craniopharyngiomas differ from adamantinomatous tumors in several important respects. These include the almost exclusive occurrence of papillary tumors in adulthood and their more uniform appearance on both CT and MR imaging. However, a preliminary analysis of our data suggests there are no significant differences between the two lesions with respect to resectability, efficacy of radiation therapy, and over- all survival. KEY WORDS • craniopharyngioma • morphological study • endocrinology • prognosis • third ventricle C J. Neurosurg. / Volume 83 / August, 1995