Tyrosine-rich crystals associated with oncocytic salivary gland neoplasms.

OBJECTIVE: Crystalloids have been identified ultrastructurally within the epithelial cells of Warthin's tumors, but there have been no studies characterizing crystals or crystalloids in Warthin's tumors by light microscopy. The finding of abundant needle-shaped crystals in a fine-needle aspirate of a cystadenoma of the parotid prompted us to examine the prevalence of crystals and crystalloids in oncocytic salivary gland neoplasms. DESIGN: Ninety-seven oncocytic neoplasms (93 Warthin's tumors, 3 cystadenomas, and 1 oncocytoma) excised at our institution between 1950 and 1996 were examined, to identify crystals. Neoplasms with crystals were further characterized by means of a variety of histochemical stains and electron microscopy. Ninety-nine pleomorphic adenomas were similarly reviewed. RESULTS: Seven cases with crystals were identified. Five of these were Warthin's tumors, 1 was a cystadenoma, and 1 was an oncocytoma. The crystals were noted within tumor cysts but were not limited to the neoplasms. The crystals were predominantly either needle-shaped or tabular, but some cases contained mixtures of both as well as intermediate forms. They stained pink with hematoxylin-eosin, although the tabular forms also exhibited a focal yellow hue. The crystals were not discernible under polarized light. They stained a red-brown color with Millon's reagent, which indicated the presence of tyrosine. Trichrome, periodic acid-Schiff stain with diastase, alcian blue (pH 2.5), and Congo red stains were negative. Electron microscopy revealed sharply defined, elongate, electron-dense structures with periodicity, both extracellular and within epithelial cells. No crystals or crystalloids were identified in any of 99 pleomorphic adenomas reviewed. CONCLUSIONS: The findings indicate that tyrosine-rich crystals associated with several oncocytic salivary gland neoplasms are morphologically, histochemically, and ultrastructurally distinct from previously described tyrosine-rich crystalloids and collagenous crystalloids of pleomorphic adenomas. Although the crystals appear to form by the assembly of small units within epithelial cells, the exact mode of formation remains unclear.

Fine needle aspiration of signet-ring cell lymphoma. A case report with differential diagnostic considerations.

BACKGROUND: Signet-ring cell lymphoma is an unusual morphologic variant of non-Hodgkin's lymphoma that, although well described histologically, is scarcely mentioned in the cytology literature. Its main significance lies in its potential for diagnostic confusion with more common lesions containing signet-ring cells. CASE: A 50-year-old, white male presented with a two-month history of persistent cervical lymphadenopathy and fatigue. Fine needle aspiration of a 2-cm, left, submandibular lymph node revealed classic signet-ring cells among small and large lymphoid cells. Also noted were multivacuolated cells. The background of the smears showed many vacuolated structures analogous to the lymphoglandular bodies seen in lymphoid proliferations without signet-ring cells. CONCLUSION: The differential diagnosis of signet-ring cell lesions by fine needle aspiration includes signet-ring cell lymphoma, sinus histiocytosis and metastatic adenocarcinoma, liposarcoma and melanoma. When confronted with such an aspirate, additional material should be obtained for immunocytochemical or flow cytometric analysis.

Using adult learning principles for perioperative orientation programs.

New graduates and experienced nurses who choose perioperative nursing need comprehensive training because of the specialized nature of the OR. A comprehensive orientation program results in quality care for patients. This article presents four adult learning principles and strategies for orienting new nurses to the OR. The strategies suggest a framework for developing, organizing, or revising a perioperative nursing orientation program. The program gives nurses who are interested in perioperative nursing the opportunity to enter this specialty.

Smallholder farming of the greater cane rat, Thryonomys swinderianus, Temminck, in southern Ghana: a baseline survey of management practices.

Baseline management practices and productivity of captive greater cane rats were studied between February and July 1992 using questionnaires with 33 practising and former farmers in 16 villages in three regions in southern Ghana. The colony sizes were relatively small, ranging between 1 and 96, with nearly a 100% farmer drop-out rate. The mean litter size of the greater cane rats in this study was 4.8+/-0.13, with the young being weaned at 8.8 weeks old. Although nearly all the farmers interviewed (90.9%) had long-term commercial intentions, a number of problems militating against their objectives were encountered. These included lack of technical support on proper management practices for efficient production, housing design, dry season feeding, sex determination and the acquisition of foundation stock. In conclusion, these studies have shown the generally poor state of the greater cane rat industry in Ghana, which requires research into almost all aspects of the productivity of this animal under captive breeding.