Potential pitfalls of needle tract effects on repeat thyroid fine-needle aspiration.

BACKGROUND: Fine-needle aspiration (FNA) is a screening and diagnostic tool used in the evaluation of thyroid nodules. Its use has resulted in an increase in the ratio of malignant versus benign thyroid nodules undergoing surgical excision. However, the FNA procedure produces some histological and cytologic alterations, which may lead to misinterpretation on repeat FNA. The goal of the current study was to characterize FNA-induced morphological alterations and their potential influence on interpretations in repeat FNA specimens. METHOD: Thyroidectomy specimens that had benign histological diagnoses and for which previous FNA specimens were available were retrieved. The FNA-induced histological alterations were evaluated and grouped based on the interval between the FNA procedure and surgical excision. Repeat thyroid FNA specimens with a cytologic diagnosis of "atypical cells/follicular lesion" were reviewed. Worrisome cytologic features that might occur after the previous FNA procedure were discussed. RESULTS: Needle tracts were identified in 68 of the 96 thyroidectomy specimens studied. FNA-induced histological alterations included hemorrhage, granulation, exuberant fibroblastic reaction, reactive follicular cells, infarction, and scarring. The presence of plump endothelial cells, myofibroblasts, and, particularly, reactive follicular cells with nuclear grooving and nuclear clearing are potential pitfalls in repeat FNA and these changes are reported to peak within 20 to 40 days after the FNA procedure. Sixteen of 152 repeat FNA cases were diagnosed as atypical cells/follicular lesion, and FNA-induced changes might have contributed to the diagnosis in 2 of these 16 cases. CONCLUSIONS: Cytologists should be aware of atypical cellular changes caused by previous FNA procedures. Although uncommon, these changes may become potential pitfalls in the cytologic diagnosis of repeat thyroid FNA specimens.

Cytomorphologic features of primary anaplastic large cell lymphoma of the psoas muscle: a case report and literature review.

Ki-1 (CD30) positive anaplastic large cell lymphoma (ALCL) is an uncommon malignancy, which may present with nodal as well as extra-nodal disease. Primary skeletal muscle Ki-1 (CD30) positive ALCL is an even rarer event with few cases reported in the literature and only some with published cytomorphologic features. An 83-year-old woman underwent a fine needle aspiration (FNA) of a psoas muscle mass. Smears demonstrated a predominantly discohesive population of large pleomorphic cells. The nuclei were hypechromatic and lobulated, with often multinucleation. Nucleoli were prominent in a subset of cells. Cytoplasmic vacuolization was also present. No lymphoglandular bodies were identified. A cytodiagnosis of malignant cells favoring metastatic melanoma vs. poorly differentiated carcinoma was rendered. Morphologic and immunohistochemical features later revealed a primary psoas muscle Ki-1 (CD30) positive ALCL with negative staining for anaplastic large cell lymphoma kinase (ALK). Cytologic features of ALCL mimic epithelial neoplasms, sarcomas, melanoma and other lymphomas. Although rare, ALCL should be a diagnostic consideration when discohesive pleomorphic malignant cells are encountered on FNA of a muscle neoplasm.

Columnar cell lesions and pseudoangiomatous hyperplasia like stroma: is there an epithelial-stromal interaction?

The significance of association between cancer and its microenvironment has been increasingly recognized. It has been shown in animal models that interaction between neoplastic epithelial cells and adjacent stroma can modulate tumor behavior. Carcinoma associated stromal cells can transform normal epithelial cells into neoplastic cells. In breast, columnar cell lesions are non-obligate precursors of low grade ductal carcinoma in situ. Columnar cell lesions can be seen intimately associated with PASH-like-stroma, a lesion we termed as CCPLS. Our aim is to investigate epithelial-stromal interactions in CCPLS and compare them to PASH without columnar cell lesions in breast core needle biopsies. Normal terminal duct lobular unit (TDLU) epithelium was seen in association with columnar cell lesions as well as PASH. Eight (8) cases of each category were examined by a panel of immunostains: CD117 (C-kit), CD34, CD105, bFGF, AR, ER-beta, MIB-1. We observed a markedly decreased expression of c-kit in columnar cell lesions compared to TDLU-epithelium. CD105 showed a quantitative increase in activated vessels in CCPLS compared to PASH. A subset of CCPLS and PASH were androgen receptor positive. A strong nuclear positivity for ER-beta is observed in the epithelium and stroma of all CCPLS cases. We conclude that (1) activated blood vessels predominate in CCPLS; (2) A molecular alteration is signified by c-kit loss in columnar cell lesions; (3) ER-beta and androgen receptor positivity indicate CCPLS are hormonally responsive lesions. Our study suggests an intimate vascular and hormone dependent epithelial-stromal interaction exists in CCPLS lesions.