Diagnostic Cytopathology最新文献

Intrathyroidal thymic carcinoma (ITTC) is a rare malignant thyroid tumor that is similar to thymus epithelium-related tumors. Herein, we report a case of ITTC diagnosed by fine-needle aspiration cytology (FNA). A 55-year-old male presented with a slowly increasing cervical mass. Cervical ultrasonography revealed an irregular mass measuring 3.7 × 2.5 × 2.1 cm. FNA was performed. Cytological findings showed that the tumor was highly cellular and tumor cells were arranged in islet-like clusters accompanied by lymphocytes. The tumor cells had a high nuclear-to-cytoplasmic ratio. The nuclei were round to ovoid or spindle-shaped. The fusiform tumor cells exhibited a regular streaming arrangement, similar to squamous cell carcinoma. Immunocytochemically, the tumor cells were positive for CD5 and c-KIT. Pathological examination of the resected thyroid specimen revealed confluent cell nests of epithelioid and spindle cells with significant lymphocyte and plasma cell infiltration throughout the tumor. Immunohistochemically, the tumor cells were positive for cytokeratin, CD5, c-KIT, and p63, and negative for TTF-1 and thyroglobulin. Therefore, the tumor was diagnosed as ITTC. Although ITTC is rare, it should be considered in the differential diagnosis of a mass in the lower pole of the thyroid gland that exhibits large cohesive islet-like clusters with numerous lymphocytes and features resembling those of squamous cell carcinoma.

Compared to myelomatous effusions, there is a lack of studies that specifically address hematolymphoid plasmacytic effusions (HPEs). We conducted a retrospective review study over 15 years to investigate the prevalence, cytologic patterns, potential interpretation pitfalls, and clinical associations of HPEs. Serous effusion fluids in which plasmacytoid and plasma cells represented more than 10% of effusion cells were classified as HPEs. We extracted relevant clinical, laboratory, and follow-up data for each patient. We found six patients [age range: 60–88, average age: 73, male to female ratio 1:1] with HPEs that constituted 0.2% of serous effusions. Relevant clinical history prompted us to consider HPEs and include plasma cell immunomarkers in cellblock sections. Light chain-restricted plasmacytic cellular infiltrates confirmed the cytologic diagnosis in the absence of fluid flow cytometry. We have recognized three cytomorphologic patterns: pure plasmacytic infiltrates, lymphoplasmacytic infiltrates, and plasma cells intermixed with other cellular constituents. Four patients had multiple myeloma (two patients with pure high-grade large pleomorphic myeloma cells, two patients with mature plasma cells intermixed with inflammatory cells), one patient had marginal zone lymphoma, and another patient had lymphoplasmacytic lymphoma. The patients had similar clinical features with even kappa (3 cases) and lambda (3 cases) light chain distribution. HPEs are uncommon malignant effusions that occur in elderly patients with multiple myeloma and low-grade B-cell lymphomas. High-grade myeloma cells can be confused with hematolymphoid and non-hematolymphoid malignancies, whereas mature plasma cells in multiple myeloma and low-grade lymphomas can be misinterpreted as reactive plasmacytosis. Cellblock immunocytochemistry is a valuable diagnostic tool.

Fine-needle aspiration (FNA) or core needle biopsy via EBUS procedure is commonly used to assess suspicious lung nodules. Alveolar macrophages are commonly seen in these specimens. In cases when hypercellular specimens with large aggregates of alveolar macrophages are encountered, especially when they show epithelioid morphology, vacuolated cytoplasm, and significant cytological atypia, including marked anisonucleosis and intracytoplasmic inclusion, they can be mistakenly interpreted as “lesional cells” during rapid on-site evaluation (ROSE) and cease the EBUS procedure prematurely. It is important to keep in mind that epithelioid alveolar macrophages may mimic lung neuroendocrine tumor (NET), lung adenocarcinoma, or even metastatic process. Cytoplasmic pigmentation and immunohistochemistry analysis can be extremely useful to prevent a false diagnosis of malignancy.