Cytogenetic Observations in 13 Cystadenolymphomas (Warthin's Tumors) Anders Nordkvist, Joachim Mark, Rigmor Dahlenfors, Mats Bende, and GOran Stenman ABSTRACT: The cytogenetic findings in 13 cultured Warthin's tumors (papillary cystadenoma lymphomato- sum) are reported. Only one case showed an abnormal stemline. This was pseudodiploid and character- ized by three different reciprocal translocations and one deletion. Small abnormal sidelines, however, were seen in three additional cases. All except one of the 12 tumors with a normal stemline contained variant cells. These showed a variety of numerical and/or structural aberrations. From this study it is obvious that to determine whether or not cytogenetically distinctive subgroups actually exist in cys- tadenolymphomas (as in pleomorphic adenomas) the number of cases must be greatly amplified. INTRODUCTION Papillary cystadenoma lymphomatosum or Warthin's tumor is a peculiar benign salivary gland neoplasm of debated ori- gin. Currently, it is thought to originate from possibly hetero- topic salivary ductal structures included in normal lymph nodes developing within the gland [1, 2]. The neoplastic part of the encapsulated tumor consists of columnar epithelium lining the usually multiple cysts. The surrounding, more or less abundant lymphoid tissue is a non-neoplastic compo- nent. Figure I a, b, and c illustrates the histologic character- istics and proposed pathogenesis of cystadenolymphomas. The sometimes multiple tumors almost always occur in the parotid gland, usually in elderly patients. In contrast to pleo- morphic adenomas (mixed tumors), malignant transforma- tion of Warthin's tumors is very rare [1, 2]. Chromosomal studies of cystadenolymphomas are limited to two case reports [3, 4] and our previous series comprising eight cases [5]. Below we present the observations from a second series consisting of 13 tumors. MATERIALS AND METHODS All cystadenolymphomas (W no.) were located in the parotid gland. Wl0 was an incidental finding in a biopsy performed because of a diagnosed pleomorphic adenoma (reference [6], case no. 131). W12 was either a recurrence, because of a previ- ous incomplete resection, or a second primary cystadeno- lymphoma. W18, W19, and W21 were three clearly separated From the Departments of Pathology (J. M., R. D.) and Otorhino- laryngology (M. B.), Central Hospital, Sk6vde; and the Department of Oral Pathology (.4. N., G. S.), University of Gothenburg, Gothen- burg, Sweden. Address reprint requests to: Dr. Joachim Mark, Department of Pathology, Central Hospital, 541 85 Sk6vde, Sweden. Received August 18, 1993; accepted October 28, 1993. © 1994 Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010 Warthiffs tumors in the right parotid of one patient. Seven additional cases of cystadenolymphomas were excluded from the present series because of either no outgrowth in vitro or too few analyzable metaphases. Table 1 shows other clinicopathologic characteristics of the material, together with, for each case, the number of chro- mosome preparations performed and the growth periods in vitro. The methods used for tissue culture, chromosome prep- aration, and G-banding were described earlier [6]. The no- menclature follows that of ISCN (1991) [7]. This issue, how- ever, doesn't provide guidelines for stemlines or sidelines with a normal diploid or polyploid karyotype. In the pres- ent report such stemlines and/or sidelines are presented and discussed as clones. Whenever possible, 10 or more ceils were karyotyped from each case. Fluorescence in situ hybridization (FISH) was performed on interphase nuclei from W16, W18, W19, and W21. Whole chromosome painting probes (Imagenetics, Framingham, MA) for chromosomes 2, 8, and 11 were used. The condi- tions for hybridization and posthybridization washes were as recommended by the manufacturer. All hybridizations were performed for 24-48 hours. Slides were examined using a Zeiss Axiophot epifluorescence microscope equipped with appropriate filter sets. For each probe at least 25 interphase nuclei were analyzed. Fluorescence signals were captured, digitalized, and enhanced using an image analysis system (Probemaster, PSI, USA). Color prints were produced using a Kodak XL 7700 monochrome continuous printer. RESULTS Chromosomal Findings Table 2 is a summary of the chromosomal observations. Cells with a normal karyotype predominated in as many as 12 129 Cancer Genet Cytogenet 76:129-135 (1994) 8165-4608/94/$07.00