ELSEVIER A Nonbalanced Translocation (10;16) Demonstrated by FISH Analysis in a Case of Alveolar Adenoma of the Lung Lucia Roque, Pedro Oliveira, Carmo Martins, C61ia Carvalho, Ana Serpa, and Jorge Soares ABSTRACT: Short-term cultures from an alveolar adenoma of the lung were cytogenetically examined. Of the 54 metaphases studied, 44 were characterized by an apparently normal karyotype and 10 showed a pseudodiploid karyotype: 46,XX, add(16)(q24). Fluorescence in situ hybridization studies per- mitted identification of the add(16)(q24) as a der(16)t(IO;16)(q23;q24). This is the first report of a chro- mosomal aberration in an alveolar adenoma of the lung. INTRODUCTION Alveolar adenoma of the lung is an uncommon neoplasm, first described by Youssem and Hochholzer in 1986 as a benign proliferation of the alveolar epithelium and septal mesenchyme [1]. The histogenesis of the tumor is contro- versial and a monophasic mesenchymal origin [2] for this entity has also been proposed. Benign tumors of the lung are a cytogenetically poorly characterized group of neoplasms [3-10] and, to the best of our knowledge, chromosomal abnormalities have never been assigned to lung alveolar adenomas [3, 4]. In this report we describe a clonal structural aberration in a case of alveolar adenoma of the lung studied by fluo- rescence in situ hybridization in addition to conventional cytogenetics. CASE REPORT A 55-year-old asymptomatic woman, nonsmoker, under- went surgical resection of a well-circumscribed mass of the right lobe of the lung detected in a routine chest X-ray. The resected specimen showed a well-delimited easily "shelled-out" tumor measuring 6 x 4.5 x 5 cm. Histologi- cally, it had no capsule and was formed by multiple cystic spaces varying in size and lined by plump cuboidal cells (Fig. 1) displaying immunohistochemical and ultrastruc- tural features of type II pneumocyte. Proteinaceous mate- rial presented as granules within the lumina of some of those spaces had electronmicroscopic features of surfac- tant lamella. The patient is currently well, 18 months after surgery. MATERIALS AND METHODS Cytogenetic Analysis A 1-cm 3 fresh and sterile tumor tissue sample was cul- tured as described by Gibas et al. [11]. Cells were grown in Figure I This tumor section shows multiple cystic spaces varying in size, some of them with proteinaceous content. The cysts are separated by thin fibrotic interstitial matrices. Hematoxylin- eosin x 82. From the CIPM-Portuguese Cancer Institute, Lisbon (L R., P. 0., C, M., A. S., J. S.) and Department of Histology and Cell Biology of the Medical Faculty of Lisbon (C. C.), Portugal Address reprint requests to: Lucia Roque, CIPM, Instituto Por- tugu~s de Oncologia, R. Prof Lima Rastos 1093, Lisboa Codex, Portugal. Received September 6, 1995; accepted November 1, 1995. Cancer Genet Cytogenet 89:34-37 (1996) © Elsevier Science Inc., 1996 655 Avenue of the Americas, New York, NY 10010 0165-4608/96/$15.00 SSDI 0165-4608(95)00309-6