Aspiration Cytology of Cervical Thymoma: A Case Report

An ectopic cervical thymoma is an uncommon tumor of the neck displaying the same histologic features as a mediastinal thymoma. Because of its unusual location, this mass is often confused as originating from the thyroid. In this report we describe a case of cervical type AB thymoma. Aspiration cytologic smears were highly cellular and revealed irregular tissue fragments, cohesive sheets, and clusters of crowded epithelial cells intermingled with many small lymphocytes. The epithelial cells had oval and spindle shaped bland-looking nuclei and scant cytoplasm with indistinct cell borders. Mitosis, nuclear atypia, and necrosis were not observed. The cells were focally arranged in a nesting pattern. Many small lymphocytes, a few activated lymphocytes, and lymphoid tangles were seen in the background. A cytologic misdiagnosis of "possible carcinoma" was rendered. Therefore, ectopic thymoma should also be considered in fine needle aspiration cytology of a neck mass when the smear shows epithelial and lymphoid components.

Cytology of Follicular Dendritic Cell Sarcoma on Intraoperative Touch Imprint Smears: A Case Report

Follicular dendritic cell (FDC) sarcoma is a neoplastic proliferation of FDCs. Because its cytologic findings can vary widely, both the cytomorphology and histopathology of FDC sarcoma can impose a significant diagnostic dilemma. We present cytologic features of FDC sarcoma assessed by intraoperative touch imprint. Intra-abdominal lymphadenopathies were noted in 54-year-old male with hepatitis B-virus associated liver cirrhosis. In contrast to cytologic features of classical FDC sarcoma, the tumor cells featured a large epithelioid or Reed-Sternberg cell-like shape scattered in a background with abundant inflammatory cells, which led to a mistaken diagnosis of malignant lymphoma. However, in accordance with cytologic features previously described in the literature, the tumor cells were characterized by a fragile cytoplasm with cytoplasmic processes in dendritic or reticulated patterns reminiscent of the ultrastructural features of FDC. Cytoplasmic features rendering nuclei with a tendency to form clusters or syncytial aggregates associated with reactive lymphocytes appear to be the most valuable finding in diagnosis of FDC sarcoma.