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Cervical squamous cell carcinoma metastatic to pericardial fluid—large cell balls masquerade as adenocarcinoma

A pleural based lung nodule was identified in a 52-yearold African American female with Stage IIIB squamous cell carcinoma (SCC) of the cervix during routine surveillance imaging. She presented to interventional radiology for CT guided biopsy of the nodule. During the procedure, the radiologist noted a pericardial effusion prompting further workup. Pericardiocentesis was performed and ;600 cm of sanguinous fluid was collected and sent for microbiology cultures and cytologic analysis. Toluidine blue (direct smear), Thin Prep, and a cell block were prepared in the cytology laboratory. The toluidine blue-stained preparation (Fig. 1) was composed predominantly of large rounded groups (“cannonballs”) of malignant cells with smooth community borders, features typically associated with metastatic adenocarcinoma, especially those from the breast, lung, and ovary. The ThinPrep slide (Fig. 2) was paucicellular and demonstrated many highly atypical, large single cells characterized by increased nuclear cytoplasmic ratios, enlarged, hyperchromatic nuclei with clumped nuclear chromatin, irregular contours, prominent nuclei, and dense cytoplasm. Some of the cells were multinucleated. Occasional rounded cell groups with smooth community borders were also identified similar to those seen in the Toluidine preparation (Fig. 3). The individual cells within the “cannonballs” demonstrated pronounced nuclear pleomorphism and dense cytoplasm admixed with cellular debris. Flattened cells with hyperchromatic nuclei were seen at the periphery of these groups. The cell block was abundantly cellular with many two dimensional ovoid groups and atypical cells, commonly referred to as squamous eddies, some with central necrosis (Fig. 4). The nuclei were hyperchromatic with clumped chromatin and showed marked pleomorphism. Occasional cells demonstrated prominent nucleoli. Atypical mitotic figures were abundant. Occasional apoptotic bodies as well as keratin pearls were identified within the large groups. The cytoplasm was dense and eosinophilic and intercellular bridging was evident in some areas. The morphology appreciated in the cell block was compared to the patient’s original cervical biopsy in 2009 and was similar. In addition, immunohistochemical stains were performed. The malignant cells were positive for p63 and cytokeratin 5/6 and negative for p16, TTF-1, MOC-31, calretinin, and WT-1. Initial review of the toluidine blue preparation and subsequent ThinPrep may have rendered an erroneous diagnosis favoring adenocarcinoma due to the presence of large cell balls with smooth community borders. The patient’s history, adequate cell block, and immunohistochemical stains confirmed the diagnosis of metastatic SCC. Although malignant pericardial effusions occur infrequently, they can be the initial presentation of metastatic disease. Carcinomas (most often lung and breast adenocarcinoma) are the most common source followed by lymphomas, sarcomas, and melanomas. SCC Department of Pathology, Loyola University Medical Center, Maywood, Illinois *Correspondence to: Brent Arville, DO Department of Pathology Loyola University Medical Center 2160 S. First Avenue Maywood, IL 60153. E-mail: brentarville@gmail.com Received 6 June 2014; Revised 4 February 2015; Accepted 30 March 2015 DOI: 10.1002/dc.23288 Published online 5 May 2015 in Wiley Online Library (wileyonlinelibrary.com).