Case 3 -

Pleomorphic Adenoma with Atypia Zubair W. Baloch

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Clinical History: 55-year old woman with a 4.0 cm left parotid mass. The mass has been present for 10-years and has grown slowly to the present size. No complaints of pain or facial numbness and weakness. Case 3 - Figure 1 Diff-Quik® stained air-dried smear showing epithelial cells and magenta / eosinophilic stromal material. Case 3 - Figure 2 High power of the Diff-Quik® stained smear epithelial cells embedded within the stroma. Case 3 - Figure 3 High power of the Diff-Quik® stained smear showing a small tissue fragment containing cells with enlarged nuclei. Case 3 - Figure 4 Papanicolaou stained smear showing background stromal material with groups of epithelial cells arranged in "acinar" arrangement. Case 3 - Figure 5 High power of the Papanicolaou stained smear showing epithelial cells with granular cytoplasm arranged in cohesive groups. Case 3 - Figure 6 High power of the Papanicolaou stained smear showing epithelial cells with granular cytoplasm arranged in cohesive groups. Case 3 - Figure 7 Papanicolaou stained smear showing bi-nucleate atypical epithelial cell. Diagnosis: Pleomorphic Adenoma with Atypia Pleomorphic adenoma is the most common tumor of the parotid gland The sensitivity and specificity of the cytologic diagnosis of pleomorphic adenoma has been reported as 93% and 99% respectively. Histological variability can occur in pleomorphic adenoma, with a variety of patterns showing varying combinations of epithelial and mesenchymal-like tissue As the architectural and cellular patterns vary considerably between different parts of the same tumor, this may cause difficulty in fine needle aspiration (FNA) cytology interpretation. The major diagnostic causes of diagnostic problems in the cytologic diagnosis of pleomorphic adenoma include: Cellular atypia - mistaken for malignant transformation Nuclear pleomorphism and mitotic activity can occur in FNA specimens of pleomorphic adenomas. This is more common in long standing tumors and has been suggested as an ancient change. Mitotic figures are rare in pleomorphic adenoma. Cystic change - can lead to squamous metaplasia and misdiagnosed as squamous cell carcinoma Cylindromatous pattern - often mistaken for adenoid cystic carcinoma It has been shown that the cellular atypia in pleomorphic adenoma is due to abnormal DNA content, which is polyploid and not aneuploid. References: Jayaram G, Verma AK, Sood N, Khurana N. Fine needle aspiration cytology of salivary gland lesions.J Oral Pathol Med. 1994 Jul;23( 6):256-61. Schindler S, Nayar R, Dutra J, Bedrossian CW. Diagnostic challenges in aspiration cytology of the salivary glands.Semin Diagn Pathol. 2001 May;18( 2):124-46. Stewart CJ, MacKenzie K, McGarry GW, Mowat A. Fine-needle aspiration cytology of salivary gland: a review of 341 cases.Diagn Cytopathol. 2000 Mar;22( 3):139-46. Cajulis RS, Gokaslan ST, Yu GH, Frias-Hidvegi D. Fine needle aspiration biopsy of the salivary glands. A five-year experience with emphasis on diagnostic pitfalls.Acta Cytol. 1997 Sep-Oct;41( 5):1412-20. Yang GC, Waisman J. Distinguishing adenoid cystic carcinoma from cylindromatous adenomas in salivary fine-needle aspirates: the cytologic clues and their ultrastructural basis.Diagn Cytopathol. 2006 Apr;34(4): 284-8. Kawahara A, Harada H, Kage M, Yokoyama T, Kojiro M. Characterization of the epithelial components in pleomorphic adenoma of the salivary gland. Acta Cytol 2002; 46 : 1095– 100. Viguer JM, Vicandi B, Jiménez-Heffernan JA, López-Ferrer P, Limeres MA. Fine needle aspiration cytology of pleomorphic adenoma: an analysis of 212 cases. Acta Cytol 1997; 41 : 786– 94. Elsheikh TM, Bernacki EG. Fine needle aspiration cytology of cellular pleomorphic adenoma. Acta Cytol 1996; 40 : 1165– 75. Lee S-S, Cho K-J, Jang J-J, Ham EK. Differential diagnosis of adenoid cystic carcinoma from pleomorphic adenoma of the salivary gland on fine needle aspiration cytology. Acta Cytol 1996; 40 : 1246– 52. Thunnissen FB, Peterse JL, Buchholtz R Van der Beek JM, Bosman FT Polyploidy in pleomorphic adenomas with cytological atypia. Cytopathology. 1992;3(2):101-9.