IN THE NAME OF GOD FIN GARDEN KASHAN

FNA of the Parotid gland In a 22 y/o woman Case 1:

What is your diagnosis?

CHELGERD - ESFAHAN

Pleomorphic adenoma of the Parotid gland

Pleomorphic adenoma The correct diagnosis can be readily established on an adequate specimen in most cases. A mixture of mesenchymal and epithelial components of varying proportions characterizes PA.Cellularity is variable, as is the ratio of epithelial cells to stroma, with some tumor fragments composed mainly of stroma and others formed mainly by epithelial cells. When the chondromyxoid stroma is prominent, the diagnosis is generally straightforward. Diagnostic problems in PA can arise when there is selective sampling with little or no chondromyxoid ground substance and the lesion may be interpreted as a carcinoma.

Stromal cells The presence of the chondromyxoid stroma, often containing capillary vessels is of critical diagnostic value. The stromal cells are slender, spindly, or stellate mesenchymal cells that may be found singly or in clusters.They commonly merge imperceptibly with epithelial cells, but epithelial cells may be entirely separate. The most notable mesenchymal component is the myxoid or chondroid matrix, which stains on: Diff-Quik stain : an intense metachromatic, fibrillar stromal matrix Papanicolaou stain :forms irregularly shaped structures,gray-green Hematologic stains : intensely red or purple Although the stromal component is often less conspicuous on Papanicolaou stained smears, the cellular, especially nuclear, detail of the epithelial and myoepithelial cells is highlighted.

Epithelial cells The epithelial cells usually form loosely cohesive clusters that are sometimes of papillary configuration, but may also be arranged in flat sheets or sometimes tubules, and are typically intermixed with the chondromyxoid stroma. When in sheets, the epithelial cells are of equal size with scanty, pale cytoplasm and round or slightly oval nuclei with fine, evenly textured chromatin. Occasional larger epithelial cells, with well-defined eosinophilic cytoplasm and eccentric small nuclei, may be observed, but nuclear chromatin is finely granular and evenly distributed, often with tiny nucleoli. In rare instances, epithelial cells with basaloid features are arranged in ball-like structures, as commonly observed in Adenoid cystic carcinoma.

Metaplasia Various types of metaplasia that have been observed in PA are seldom evident in the needle aspirate. The epithelial cells can display squamous, oncocytic, sebaceous, or mucinous metaplasia. When either squamous, oncocytic, sebaceous, or mucinous metaplasia is prominent, the possibility of a low-grade mucoepidermoid carcinoma must be considered.

The myoepithelial cells are generally bland and may form clusters of loosely cohesive cells. Individual cells may have a spindle or plasmacytoid appearance with indistinct cytoplasmic borders and eccentric round nuclei and prominent cytoplasm. Such cells cannot be readily differentiated from epithelial cells. Myoepithelial cells

Slight variation and moderate atypia may be present focally in benign mixed tumors and should not be over-emphasized (Benign atypia). In the absence of other malignant features (e.g., increased mitoses or clinical suspicion of malignancy), severe atypia should be assessed critically and cautiously because many pleomorphic adenomas can display prominent anaplasia and still behave indolently. If the atypia is pronounced and diffuse and there are other supporting features, a diagnosis of carcinoma ex PA can be considered. Atypia

Calcification & Crystolloids Rarely, aspirates have been reported to contain calcifications resembling psammoma bodies. When present, crystalloids are useful in confirming the diagnosis of PA. Tyrosine crystalloids : yellow or pink leaf shaped structures, needle- shaped and tubular crystals Hippurate crystals : polygonal, yellow-staining Oxalate crystals: needle-shaped Collagenous crystals: radially arranged needle-shaped Amylase crystals: multifaceted with pointed ends Only tyrosine crystals have been reported in low-grade adenocarcinomas of salivary glands, but all other crystalloids have been observed only in benign PA.

PRINCIPAL CYTOLOGICAL FEATURES OF PLEOMORPHIC ADENOMA Cellular smears composed of epithelial cells blending with fibromyxoid background The presence of fibromyxoid stroma The presence of crystalloids

Differential Diagnosis Adenoid cystic carcinoma, if the epithelial cells form ball-like structures Low-grade Mucoepidermoid carcinoma, if either extensive squamous, oncocytic, sebaceous, or mucinous metaplasia is prominent

Review: hyaline cells Diff-Quik

Case 2 : FNA of the thyroid in a 55 y/o woman

Tall Cell Variant of Papillary Carcinoma of the Thyroid

Tall Cell Variant of Papillary carcinoma This variant is uncommon and occur predominantly in older patients (mean age : years) and to be large (usually >5 cm). The tall cell variant has a documented aggressive clinical behavior and showed a higher incidence of extrathyroidal extension, recurrence, distant metastasis, and mortality relative to conventional-type papillary carcinoma. When first seen, it may present as a large thyroid mass with regional lymph node metastases. Histology: This neoplasm is defined by the presence of more than 30% of the tumor as well-formed papillae covered by cells twice as tall as they are wide.

Cytology: Specimens are cellular with three- dimensional and syncytial papillary aggregates, sometimes of columnar configuration, composed of large cylindrical cells with abundant dense acidophilic (pink) cytoplasm and eccentric nuclei. Unlike conventional papillary carcinoma, mitotic figures are common; however, other conventional diagnostic nuclear features of papillary carcinoma are still present. Intranuclear inclusions are numerous. The smear pattern is somewhat similar to that observed in papillary carcinomas of the breast with eosinophilic cytoplasm. Tall Cell Variant of Papillary carcinoma

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NIASAR FALL NIASAR FALL KASHANESFAHANKASHANESFAHAN THANKS FOR YOUR ATTENTION