Diagnosis of T-cell lymphoma in body fluids: cytologic features and unusual flow cytometric findings.

OBJECTIVE: To demonstrate the unique morphologic and phenotypic features observed in cases of T-cell lymphomas presenting as effusions. STUDY DESIGN: Cytologic slides and flow cytometric histograms of 8 cases of body fluids with T-cell lymphoma were retrospectively reviewed. Morphologic features, flow cytometric histograms and immunophenotypes of the cells were evaluated. RESULTS: Three of the 8 cases showed 1 or more of the following: intermediate-to-large cells with an increased nuclear-cytoplasmic ratio, finely granular or vacuolated cytoplasm and round or convoluted vesicular nuclei with a prominent single or multiple nucleoli. Flow cytometric studies of these 3 cases showed an abnormal scatter pattern in the myelomonocytic region of the histograms. Phenotypic analysis revealed variable expression of a T-cell phenotype. The remaining cases showed the conventional morphologic and flow cytometric features of a T-cell lymphoma. CONCLUSION: Morphologic alterations of neoplastic T-cells in body fluids can result in a variety of potentially incorrect diagnoses. The unusual flow cytometric histogram can serve as a useful clue for the diagnosis of T-cell lymphoma in body fluids but could be a potential pitfall for a false negative. Detailed cytologic evaluation combined with flow cytometric study can improve diagnostic accuracy.

Cytologic findings of myxoid neurothekeoma: case report based on fine-needle aspiration cytology, immunohistochemistry, and correlating histopathology.

Myxoid neurothekeomas (nerve sheath myxomas) are rare benign cutaneous neoplasms that may morphologically mimic other myxoid neoplasms of skin and soft tissue. The cytologic and histopathologic features of this lesion may resemble various myxoid sarcomas, chordoma, myxoid neurofibroma, dermal cutaneous mucinosis, and cutaneous myxoma as well as other myxoid or chondroid neoplasms. In this study, a myxoid neurothekeoma was analyzed using multiple techniques. We found that myxoid neurothekeomas reveal a nonspecific pattern by fine-needle aspiration, including stellate cells embedded within an abundant metachromatic myxoid stromal matrix. These are cytologic features shared by various other subcutaneous neoplasms and thus may not be helpful in forming a definitive diagnosis. Histopathologically, the tumor is composed of nodules of myxoid stroma containing interspersed bland spindled and stellate cells. Immunohistochemical studies show tumor cell positivity for S-100 protein and vimentin, a profile shared by other neoplasms with similar cytologic features and therefore of little diagnostic value. The histologic and cytologic differential of subcutaneous and soft tissue myxomatous lesions is broad and, therefore, is of unique value to the cytopathologist to consider myxoid neurothekeomas among the differential of other myxomatous neoplasms.