Diagnostic pitfalls of infarcted Warthin tumor in frozen section evaluation Yaohong Tan, MD a , Oleksandr N. Kryvenko, MD a, c , Darcy A. Kerr, MD a , Jennifer R. Chapman, MD a , Christina Kovacs, MD a , David J. Arnold, MD b , Andrew E. Rosenberg, MD a , Carmen R. Gomez-Fernandez, MD a, ⁎ a Department of Pathology, University of Miami, Miller School of Medicine, Jackson Memorial Hospital, Sylvester Cancer Center, and University of Miami Hospital, Miami, FL, USA b Department of Surgery, University of Miami, Miller School of Medicine, Miami, FL, USA c Department of Urology, University of Miami, Miller School of Medicine, Miami, FL, USA abstract article info Keywords: Warthin tumor Infarct Salivary gland Metaplasia Diagnostic pitfall Warthin tumor (WT) is the second most common benign salivary gland neoplasm and has characteristic cytolog- ic and histologic findings. Fine-needle aspiration is a common and useful preoperative diagnostic technique, which sometimes leads to ischemic injury resulting in the infarction of these lesions. Infarcted WT may demon- strate variable gross and histologic alterations that may render the diagnosis challenging, particularly during in- traoperative frozen section evaluation. In this study, we collected 11 resection specimens from 9 patients with infarcted WT. Seven patients were men and 2 were women, ranging from 49 to 85 years (mean, 69). All the patients had fine-needle aspiration before the resection. Macroscopically, the tumors were tan-white and contained soft, yellow, exudative material. The histo- logic findings were variable and included necrosis, ghosts of papillae, squamous metaplasia, cholesterol clefts, foamy macrophages, multinucleated giant cell reaction, necrotizing granulomas, and fibrosis. Each case predom- inantly demonstrated 1 or 2 of these histomorphologic features. In the permanent sections, additional sampling revealed foci of residual viable WT in 8 cases. Three cases were completely infarcted; however, they all had ghost- like papillae in which the architecture of WT was evident. Infarcted WT may present a diagnostic challenge during intraoperative frozen section evaluation. Associated morphologic alterations may preclude a definitive diagnosis of WT and may mimic malignancy. Awareness of the gross and microscopic features associated with infarcted WT is important, particularly for accurate frozen sec- tion evaluation of these salivary gland tumors. © 2016 Elsevier Inc. All rights reserved. 1. Introduction Warthin tumor (WT, adenolymphoma; papillary cystadenoma lymphomatosum) is the second most common benign salivary gland neoplasm. The WT is almost exclusively limited to the parotid glands and the periparotid lymph nodes [1]. In the parotid, it usually is located in the tail of the gland and is multicentric in 10% to 20% of patients and bilateral in 5% to 15% [2,3]. The WT arising from minor salivary gland is very rare, with an incidence ranging from 0.1% to 1.2% [2,4]. Clinically, the tumor is cystic, painless, slowly growing, and firm to fluctuant at palpation. The WT has a higher incidence in older people with a mean age at diagnosis of 62 years (reported range of 12-92 years) and is strongly associated with smoking. Studies have shown that smokers had a 4- to 40-times greater risk than nonsmokers [5,6]. In the early lit- erature, WT was reported to have a distinct male predilection, with a male-to-female ratio of 10:1. But more contemporary studies have shown that WT had a similar incidence in female and male, with a 1:1 ratio [7,9]. This change is likely largely due to the increased prevalence of smoking in women in the past few decades. The pathogenesis of WT still remains unknown and controversial, al- though several theories have been proposed. The most widely accepted theory is that these tumors are caused by heterotropic salivary duct ep- ithelium in the intra/paraparotid lymph nodes. By immunohistochemis- try, the luminal and basal epithelial cells of WT have similar features as those of the striated duct cells and basal cells of the excretory duct of the salivary gland [10]. Stimuli including benzopyrene, arsenic, and N- nitrosoguandien from tobacco have been shown to irritate the ductal epithelial in the lymphoid tissue and result in oncocytic metaplasia and tumorigenesis [1]. Macroscopically, WT is an encapsulated, fluctuant soft tissue mass with smooth outer surfaces. Cut sections show multicystic dark brown spaces with motor oil-like fluid; papillary projections may be present. Microscopically, WT is composed of cysts and papillae arranged with distinct epithelial lining and underlying lymphoid tissue. The epithelial component has 2 layers of granular eosinophilic cells with prominent Annals of Diagnostic Pathology 25 (2016) 26–30 ⁎ Correspondence author at: University of Miami Hospital, Department of Pathology, Suite 4058, 1400 NW 14th Avenue, Miami, FL 33136. Tel.: +1 305 243 9695; fax: +1 305 689 1326. E-mail address: cgomez3@med.miami.edu (C.R. Gomez-Fernandez). http://dx.doi.org/10.1016/j.anndiagpath.2016.08.004 1092-9134/© 2016 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Annals of Diagnostic Pathology