We present a case in which a primary cytodiagnosis of Langerhans cell histiocytosis (LCH) of the skull was made using squash preparations. The patient, a 25-year-old male, presented with raised intracranial pressure and decreased visual acuity. Magnetic resonance imaging revealed a large skull lesion with osteolytic features in the left frontal bone. The patient underwent surgical resection by the extended basal frontal epidural approach. The squash preparation smears were cellular and demonstrated a mixed population of small, mature lymphocytes, eosinophils, and a high histiocytes content. The histiocytes occurred as isolated or loosely cohesive and clustered. They possessed abundant cytoplasm with rounded cell shape and had characteristic nuclear features, composed of fine chromatin and delicate nuclear membranes. The cytologic features of these histiocytes were consistent with Langerhans cells (LCs). A final impression of LCH of the skull was rendered. Subsequent histopathology confirmed the diagnosis. LCs reacted with both S-100 protein and CD1a immunohistochemically. The demonstration of Birbeck granules on electron microscopic study was also noted. Whenever squash preparation yields a mixed population of mature lymphocytes, eosinophils, and histiocytes, the cytologists should be aware of and consider LCH as a diagnostic possibility.

The cellular features of adeno‐endocrine‐cell carcinoma of appendiceal origin are presented. The pleural fluid contained metastatic predominantly atypical cells in linear cluster accompanied by numerous mesothelial cells. The cells had small round nuclei, with a slight tendency to molding; nucleoli were absent. The cytologic findings in Papanicolaou‐stained smears of the pleural fluid suggested a metastatic small‐cell carcinoma of the lung. Subsequently, adeno‐endocrine‐cell carcinoma of the appendix was demonstrated at autopsy. Reports of such occurrences are few; no study, to the best of our knowledge, has previously documented the cytologic diagnosis in pleural fluid. Diagn. Cytopathol. 16:522–525, 1997. © 1997 Wiley‐Liss, Inc.

Hepatocellular carcinoma (HCC) metastasizes to the brain is rare instances. In published series and case reports of metastatic HCC, diagnosis of central nervous system metastases has been determined by histologic methods. We present a case of metastatic HCC of brain diagnosed by squash cytologic preparation. A 69-year-old male, HCV positive, suffering from post-hepatitic cirrhosis, initially diagnosed at age 68 with HCC presented with headaches of increasing frequency and severity. A computed tomography scan confirmed a 3-cm nodule in the right parietal lobe of the brain. Squash cytology was performed intraoperatively and preparations of a small tissue fragment resected from the mass showed medium-to-large-sized, well-cohesive clusters or sheets of uniform tumor cells. The tumor cells are highly cellular and contain solitary tumor cells in loose groupings as well as many fragments. They also appear somewhat bizarre and contain large, round, or ovoid nuclei with prominent nucleoli. Cytologic diagnosis of metastatic HCC was rendered reported and confirmed by a subsequent frozen section examination. To the best of our knowledge, this is the first reported case in which HCC was reported as brain metastasis, by using squash cytology. We suggest that intraoperative squash cytologic examination be viewed as a useful initial approach in the diagnosis of metastatic brain tumor.

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